INTRODUCTION TO SYNTHESIZERS - hol.gr

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INTRODUCTION TO SYNTHESIZERS
by Thomas Kolb
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Introduction
On these pages I would like to introduce you to the fascinating world of music electronics and synthesizers.
A synthesizer is an electronic musical instrument. The difference between electronic instruments and acoustic
instruments can be illustrated with a few examples: a flute creates its sound by setting a pipe of air into
resonation; a violin makes a sound as the player "bows" a string into self-oscillation, which is then transferred
and amplified by a specially crafted wooden "case". Acoustic instruments are all mechanical - something must
be moving or resonating for sounds to be created.
Synthesizers are different: they don't create direct sounds, but only electric signals. Without loudspeakers or
headphones attached to the synthesizer, it will not be able to make anything even remotely audible - well at
least nothing apart from the clicking of the keys. This is really not very far from how your CD-player works: it
doesn't make direct sounds either, only electric signals that are turned into sounds by your stereo speakers or
your headphones.
Synthesizers are usually equipped with a piano style keyboard. Each key of the keyboard is actually a switch by
which the user can switch electronic circuits on and off. Keyboards are by far the most popular input devices,
but the user can also choose to use mouthpieces, strings, guitar-like devices, drum pads or a computer to
control the synthesizer.
Synthesizers are extremely versatile instruments. They can be made to imitate any other instrument - from
reed instruments to drums. But the true power of the synthesizer is its possibility to create completely new, yet
unheard sounds - even if not all of these sounds are useful for musical purposes.
The early years
The first generation of synthesizers were extremely difficult to handle. They were large as bookshelves, cost
hundreds of thousands of dollars, and could only be found in the most advanced electronic music studios.
Moog Modular II
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The essence of sound
In order to fully understand how synthesizers work, we must first understand the physics behind the
phenomena we perceive as "sound". So, what is a sound?
The air surrounding us consists of gas-particles. If you force a number of these particles to move, they will
create a wave traveling from one particle through the next, in all directions away from the source. It's just like
when you throw a stone into a pond - the water particles will create ripples or waves, moving away from the
center.
Sound-waves are also initiated from a source, like a car engine, a slamming door or a finger plucking a guitar
string. These ripples, or vibrations travel through the air and reach our ears, where they will set our eardrums
into motion. This motion is in turn perceived by our brains and interpreted as a "sound".
Of course there are many different sounds. Any non-deaf person can hear the difference between a barking dog
and a singing voice. But how can we do that?
A sound-wave has three main properties. These properties are:
• timbre
• pitch
• volume
Timbre
The tonal color or timbre is probably the most important factor for the character of a sound.
Let's illustrate it with an example: say that you play and hold a single note on the accordion. Most of us will
instantly recognize the sound as being an accordion.
If you now play the same note on the flute, you will probably hear the difference. Even if both instruments play
the very same note and at the same volume, you can easily distinguish between the two sounds. That is
because they have different timbres - different sound colors.
We already mentioned that the sound is just a vibration in the air. Now, if you make this vibration visible, for
instance by using an instrument called an oscilloscope, you will see that different timbres have different
waveforms. This may sound very technical indeed, but the word "waveform" is so commonly used in synthesizer
related text, that you should be familiar with it. We can just say that different waveforms simply "sound"
different.
So, what does such a sound-wave look like? Let's look at an example!
(Click on the loudspeaker icon to listen to the waves!)
A simple sound-wave
This is a very simple waveform, called a sawtooth wave. You can probably see why it is called that: the wave
has a repeating "sawtooth-like" pattern. This pattern is the timbre of the waveform. Generally you can say, that
the more "sharp" edges a waveform has, the more "harsh" it sounds.
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Pitch
The repeat rate of the pattern is called the frequency of the waveform. The frequency determines the pitch of
the sound - a sound with higher frequency will be perceived as a higher tone. To take an example, a female
human voice has a higher frequency than a male voice.
Take a look at the wave in the next illustration. It is also a sawtooth wave, but its frequency is exactly two times
higher than the one in the previous example. The result is a sound exactly one octave higher.
The same wave, but one
octave higher
In physics, frequencies are measured in the unit Hertz (Hz), which is the same as repetitions per second. A
person with normal hearing can perceive sounds with frequencies from around 20 repetitions per second (20 Hz)
to around 18 000 repetitions per second (18 kHz).
If the frequency is lower than 20 Hz, we will no longer perceive the wave as being a sound, but more like a
"throbbing" in the air. These sounds are called "subsonic sounds", or "infrasounds". Even if subsonic cannot be
heard by humans, they can cause some strange phenomena, like shopping windows starting to vibrate by no
apparent reason. Quite often these vibrations are caused by trucks passing by, or aircraft taking off many miles
away. Many animals, like elephants and manatees actually use these sounds to communicate with each other.
On the other side, frequencies beyond the top border are called "ultrasonic sounds", or "ultrasounds".
Ultrasounds can not be perceived by humans at all, but as you probably know, the hearing of many animals can
stretch way into the ultrasonic range. Dog-whistles emit ultrasonic sounds at around 40 kHz, which are easily
heard by our four-footed friends. Bats also use ultrasounds to localize their prey in flight.
To be able to perceive the pitch and the timbre of a sound, the waveform must be periodic - otherwise we can't
tell how often the waveform is repeating. Of course there are also non-periodic, or random waveforms. These
are perceived by the human ear as noise - such as the sound of a distant waterfall or radio static.
Noise
Other waveforms are of course not as simple as the ones in the examples above, but far more complex. Well,
here is a beautiful one taken from the Korg X3 synthesizer!
Volume
A more complex waveform
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The volume of the sound the same as the amplitude of the waveform. The amplitude is the "height" of the
waveform, or the height difference between the lowest and the highest part of the wave. The higher the
amplitude, the louder the sound. The roar of a jet engine has for instance a much higher amplitude than a
whispering voice.
It's just like the difference between a pebble that your through in the pond, and a boulder. Trust me, the
boulder will make much higher ripples!
The amplitude of a sound is also a measurement of its energy state - the louder the sound is, the more energy it
carries. It is probably hardly a surprise that sound waves with very high energy can damage your ears. And not
just your ears: the roar of a jet engine from at close range can destroy the blood vessels in the human body.
Extremely high-energy sounds can even be used to shatter rocks.
But since our goal is not rock shattering, let us instead look at how a synthesizer works to create artificial
sounds!
The oscillators
Now we understand the principle behind our sonic environment. Let's see how we can create artificial sounds
with a synthesizer.
First of all we need something to generate a soundwave with. A device to create a wave with is usually called an
oscillator.
The first synthesizers used analog electronic oscillator circuits to create waveforms. These units are called VCO's
(Voltage Controlled Oscillator). More modern digital synthesizers use DCO's instead (Digitally Controlled
Oscillators).
A simple oscillator can create one or two basic waveforms - most often a sawtooth-wave - which we have
already looked at in the previous chapter - and a squarewave. Most synthesizers can also create a completely
random waveform - a noise wave.
Sawtooth-wave
Square-wave
Noise
These waveforms are very simple and completely artificial - they hardly ever appear in the nature. But you
would be surprised to know how many different sounds that can be achieved by only using and combining these
waves.
A synthesizer has a function to "map" the wave over the entire keyboard range, and make the frequency of the
wave shift from one key to another. Since the frequency of a soundwave is the same as its pitch, we can use the
keyboard to play the wave as an instrument.
Filters
To be able to vary the basic waveforms to some extent, most synthesizers use filters. A filter is an electronic
circuit, which works by smoothing out the "edges" of the original waveform.
If you listen to a sawtooth wave, you will find it rather "harsh" - because the waveform has a lot of sharp
"edges". These edges are in the acoustic terminology called overtones.
Now, if we apply a filter to the waveform, some overtones will be removed - and the waveform will become
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more "rounded". The more overtones are being removed, the more "rounded" or "dull" the sound will become.
The filter in other words control the brilliance of the sound.
You decide how the filter will operate and how much of the overtones will be removed. The point where the filter
will start cutting off overtones is called the cutoff frequency. You can say that overtones higher than the cutoff
frequency will not be let though the filter.
As the filter is opened up, the cutoff frequency is shifted higher up, and more overtones are let to pass through.
The effect is the sound gradually getting brighter.
Click on the icon to the left to hear a synthesizer
pattern with a gradually opening filter.
Most synthesizer filters can not only remove overtones, but also create completely new ones by distorting the
original waveform near the cutoff frequency. This feature is called resonance and can create very interesting
sounding results.
The amplifier
Click on the icon to the left to hear a synthesizer
pattern with a gradually increasing resonance.
To control the volume of a sound in the synthesizer, the signal is passed through an amplifier circuit. The
amplifier can raise, or lower the height of the waveform, thereby raising or lowering the volume of the sound.
It is very important to keep in mind that when we speak about amplifiers in synthesizer terminology, we don't
mean the same kind of amplifier that is required to drive a pair of speakers. Synthesizer amplifier circuits only
affect the waveform, and not the sound as it emerges from the Line Out jacks of the instrument. If we want to
connect loudspeakers to the output of the synthesizer, we still must use some kind of power amplifier.
We can conclude this chapter in the following diagram:
The oscillator creates
a waveform
The filter rounds down the wave to the
requested amount of brilliance
Now, who said sound synthesis was complicated?
Envelopes
The wave is amplified by the amplifier
to the requested sound level
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Now we have the minimal requirements to create a synthesizer voice. But we still need to make this sound
playable as a music instrument voice. Let's see what's missing!
First of all, natural sounds normally don't just instantly switch on and off. Sounds are hardly ever "static" but
change their character through time.
A real life sound has always a fade in and fade out period. To take an example, a drum hit begins very sharply
as the drumstick hits the skin and also fades away quite fast. The sound volume of a note on the piano will also
rise rather quickly, but will dampen much more slowly. The sound of some instruments - like for instance the
violin - can be made to sustain for a long time, while the sound of a drum inevitably fades away, regardless of if
we press the drumstick against the skin after the initial hit or not.
This behavior is called the envelope of the sound. Let us illustrate such an envelope:
Of course this is just a very simplified envelope curve, and the envelopes of acoustic sounds are a lot more
complex than this one. But we can still identify some main parts of the envelope that we will be able to use in
our synthesized sound. These parts are:
• Attack (the initial onset of the sound)
• Decay (the first fading of the sound)
• Sustain (the level at which the sound is held as long as the key is depressed)
• Release (the fade out of the sound)
This kind of envelope is often called an ADSR-envelope (by combining the initial letters of the name of the
different phases - Attack, Decay, Sustain and Release).
Envelopes for other sounds does not necessary always have to look like in the example above. For drum sounds
the sustain phase may for instance be lacking completely, since a drum sound cannot be sustained infinitely.
The amplitude envelope for a short, percussive sound with a long reverberant echo may look like the one in the
following illustration:
This kind of envelope is very well suited for drum-like staccato playing - even if the timbre itself is not a drum
sound, but a string or human voice sample.
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Of course not just the loudness of a sound changes over time, but both the timbre, and the pitch might change
between the onset and the fade-out - like how the pitch of a train whistle drops as the train passes by.
To simulate the different envelopes on a synthesizer, we must be able to control the oscillator, the filter and the
amplifier in a much more detailed way than just our basic on/off function. We want to be able to control the
envelope for each synthesizer circuit. This is done by using envelope generator circuits.
The envelope generator of the oscillator controls how the pitch changes through the duration of the sound, while
the envelope generator of the amplifier controls how the volume changes over time. The filter also has its own
envelope generator, which controls the changes in the "brilliance" of the sound.
The envelope generators on most synthesizers use the ADSR model we have looked at in this chapter. But on
some other synthesizers we have more detailed control over the envelopes of the sounds. The Casio CZ-series
synthesizers have as much as eight different envelope stages, which makes it possible to create some very
complex envelopes.
Modulation
Rapid periodic changes in a sustaining sound's pitch is called vibrato. If the periodic changes affect the loudness
of the sound instead of the pitch, it is called tremolo. Vibrato and tremolo are almost always an important part
of the sound of acoustic instruments - for instance, a sustained violin sound without vibrato will sound
surprisingly raw and unmusical. Let's see how we can achieve these effects on our synthesizer voice!
If you have read the previous chapter, you should now at least have a basic understanding of which part of the
synthesizer that controls the pitch and the volume of the sound. (Come on folks, of course I am referring to the
oscillator and the amplifier!)
Since vibrato affects the pitch of the instrument, it shouldn't be a surprise that the effect can be simulated by
applying a slight, periodic change to the oscillator wave. This is called modulating the oscillator. Tremolo on the
other hand affects the amplitude of a sound, so for this effect the modulation should instead be applied to the
amplifier.
Both vibrato and tremolo effects require a rather slow wave with only around two or three cycles every second.
To create this modulation wave, we must now introduce a new synthesizer component: the Low Frequency
Oscillator (LFO). Some synthesizer manufacturers use the term Modulation Generator instead.
Natural vibrato and tremolo effects tend to increase in strength as a note is sustained. For example, a flute
sound might have a tremolo effect, which begins at some point after the note has sounded, and the tremolo
effect gradually increases to some maximum level, where it remains until the note stops sounding. This is
accomplished in synthesizers by applying an envelope generator to the LFO.
Not all synthesizers allow this kind of precise control over the LFO, and quite often we can only set a delay time
before the modulation begins.
However, on most synthesizers we can select the waveform of the LFO. An LFO with a triangle- or sine-shaped
waveform applied to the pitch will give a normal vibrato, but if we change the waveform of the LFO to a
squarewave, we will achieve a different musical effect, called a trill.
Voices
Well, now we have a fully usable synthesizer voice. But we still have only one voice - so we can't play chords
yet. Even if we play five keys at once on the keyboard, we will still only hear one tone.
The first synthesizers were all like this - they are monophonic synthesizers. If you wanted to play chords, you
would have to buy more than one synthesizer - one for each tone, or use a multitrack tape recorder and
overdub the takes.
But wait a minute - why can't we put more than one oscillator, one filter and one amplifier in one instrument?
Then we could play more than one sound at once. Right?
Absolutely right! It didn't take long until synthesizer manufacturers realized this possibility, and soon four-voice
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and even eight-voice polyphonic synthesizers were available for those who could afford them. A synthesizer with
eight voices can play eight tones at the same time.
This may seem enough, but a modern synthesizer is usually equipped with 32, 64 or even 128 voices. One could
ask, why anybody would need an instrument capable of playing 64 voices at once - nobody in the right mind
would want to play (and listen to) huge 64-note chords.
Well, first of all, voices can be stacked on top of each other to create a more complex sound. A single key
depression could for instance trigger a piano voice, a string voice and a choir voice at the same time. It's easy
to realize that the available voices are quickly gobbled up when playing with such a complex voice stack.
But the main reason for having lots of available voices in one synth is the possibility to use this one synthesizer
to play more than one part in a musical piece.
Nearly all modern synthesizers are so called multi-timbral instruments, meaning that they can play several
different sounds at once. If the synthesizer is connected to a computer, it can for instance play drums, strings,
brass, bass and guitar parts - all at once, like a big one-man-band.
Now, it is important to understand the difference between polyphony and multi-timbrality.
If a synthesizer can play more than one note simultaneously, then it is polyphonic.
If it can produce a an acoustic bass sound, a piano sound and a string sound at the same time, then it is also
multi-timbral.
A 32-polyphonic, 8-timbral synthesizer can thus synthesize the sound of a 8 piece band or orchestra, as long as
there are no more than 32 notes playing at the same time. It's easy to realize that a 32-voice synthesizer is
much better suited for complex compositions than an eight-voice synth.
The polyphony of a multi-timbral synthesizer is usually allocated dynamically among the different parts
(timbres) being used. As an example, say that we have an eight-voice multi-timbral synthesizer. If at a given
instant five voices are being used for the piano part and two voices for the bass, then only one voice is left free
for an additional instrument.
However, you may not need all five allocated voices for the piano part all the time - when a voice is not being
used, it is free to be allocated to another instrument.
So what happens if you try to play more notes than what's available? Well, it depends on the internal
architecture of the synthesizer, but most synthesizers will simply turn off a voice that's already playing and
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assign it to the new note. One sounding note will simply disappear - usually the first note that you have
triggered. This side-effect is called "note stealing" and can be quite disturbing when playing large chords with
long sustaining sounds on a four- or eight-voice synthesizer.
Other methods
The synthesis method we looked at in the previous chapters is usually called subtractive synthesis. This means
that the synthesizer starts with a basic waveform (such as a sawtooth-wave) and filters this into a multitude of
variations.
Of course this is not the only way to create sounds. Some synthesizers (like the simplest synthesizer circuits on
many computer soundcards) use a method called frequency modulation or FM for short. This technique is based
on sine waves "modulating" each other. I will not describe this method any further here, but if you would like to
read more about FM-synthesis, please read my page about the Yamaha DX7 synthesizer.
A third synthesis method is called harmonic synthesis. This method uses a large number of sine waves with
different pitches and volumes, which when combined create a complex sound. This method is rather complicated
since it is almost impossible to imagine what the final waveform will sound like before all the parts are combined
together. That's why harmonic synthesis is mainly used together with computers.
One very recent method is software synthesis. A computer software is used to emulate a synthesizer and the
sound chip of the computer is used to create the sounds. The user communicates with the program by using a
set of simulated synthesizer controls on the screen, like pushbuttons, knobs and sliders.
Subtractor Polyphonic Synthesizer (Reason module)
Even it may seem strange first, these software synthesizers are just as useful as any hardware-based
synthesizer, and their capacity is often quite impressing.
There is really no way of telling if a synthesizer heard on a recording is a hardware-based synthesizer or a
software-based one such as ReBirth or VAZ Modular.
Sampling
A sampling synthesizer (or "sampler") has no internally generated sounds at all. Instead it uses external sound
sources - like acoustic instruments, the sounds of nature or the human voice.
Sampling is a digital technology - there are no tapes or other conventional recording devices involved. Instead
the external sound is analyzed by a microprocessor, chopped up into tiny pieces and stored in the sampler's
memory as a huge array of numbers. Once the sound has been recorded or "sampled", it can be mapped over
the keyboard and used exactly as the internal waveforms of the traditional synthesizers.
As recently as fifteen years ago, sampling required
extremely advanced technology, and the few sampling
musical instruments available (like the famous Fairlight
CMI) had price tags like Ferrari sports cars. Operating
these awesome workstations also required a substantial
amount of training.
Fairlight CMI III
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Today sampling technology is used in nearly every personal computer, and a sampling instrument is no more
expensive than a regular synthesizer. In computer terminology, sampling is sometimes (slightly incorrectly)
referred to as "wavetable synthesis".
A normal desktop computer with a decent 16-bit soundcard can do everything that a dedicated sampling musical
instrument can - and even with better sound quality, more functions and greater ease of use.
All that's required is some software to put this technology to work. Sampling software exists in many different
forms and shapes today, but one of the coolest software-based sampling instruments available today is the
awesome GigaSampler from NemeSys.
GigaSampler 1.5
Click on the icon to listen to the
GigaSampler!
(Miroslav Vitous Symphonic Orchestra
sample library)
(349 kB)
The theory behind sampling is the same regardless of if we are using dedicated samplers or soundcards in a PC,
so let us just focus on that for now. We mentioned that sampling works by measuring the incoming waveform
with regular intervals and storing these numbers in memory. Let's look at sampling in more detail!
Sampling frequency
The sampling circuit performs the task of analyzing the incoming sound wave and chopping it up into tiny
pieces. This part of the sampler is usually called the "analog-to-digital converter", or A/D converter for short.
This circuit is controlled by a built-in "clock". For each tick of this clock, the waveform is measured, or sampled.
To make a good recording, the clock must be ticking very fast indeed - we actually need to sample the incoming
waveform at least 40 000 times each second!
If we would sample the wave with longer intervals, we would simply miss too much of the waveform's
characteristics between the sample points to be able to make a clear reproduction.
The number of measurements each second is called sampling frequency, or sampling rate. Let us visualize the
sampling process:
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The illustration above shows a simple wave being sampled. The dotted lines show the sampling points. The
original waveform is the smooth line, and the sampled wave is the jagged line.
As we can see, the sampled version of the original wave suffers severely from the low sampling frequency. Since
the A/D-converter doesn't "know" what happens between to adjacent sample points, it will miss a substantial
amount of the wave. The result is a poor representation of the original wave, with a lot of jagged edges. These
edges will be heard as overtones not present in the original sound. This phenomena is called "aliasing".
Now let's see what happens if we double the sampling frequency!
The sampled curve is still a bit jagged, but is now much closer to the original waveform. As the sampling
frequency increases the sampled waveform is getting to look more and more like the original wave. It is fairly
obvious that a high sampling frequency is very important to achieve an authentic result.
But it shouldn't take long to figure out that a high sampling frequency will also consume available storage space
very quickly - there are simply more measurements to be stored in the memory.
Since the available memory usually is a very limited resource in a sampler, it's a tradeoff between sound quality
and sample length. Given a certain amount of memory, we can either achieve a longer sampling by lowering the
sampling frequency and thereby decreasing the sample quality, or we can achieve high quality reproduction by
sacrificing the length of the samples. It takes a lot of skill to learn how to balance these values for an optimum
performance!
Sampling resolution
A high sampling rate may still not be enough to make a good sample - we also need to have a high sample
resolution.
The resolution is the "exactness" of each individual sample. With a high resolution, each sample point will be
measured very accurately. With a lower resolution, the measurements will not be quite as exact, and a certain
amount of rounding errors will occur. Instead of getting too deeply involved with the technical aspects of this,
we can just say that a higher sampling resolution will yield a better reproduction of the original sound than a
lower resolution at the same sampling rate.
Sampling resolution is measured in the unit "bits". Usual sampling resolutions are 8-bit, 12-bit, 16-bit and 32
bit. A sampled sound with 8-bits resolution sounds very gritty and "coarse" compared with a 16-bit sample.
Almost all modern samplers are capable of 16-bit resolution sampling, or even 32-bit resolution sampling, which
yields a very high quality reproduction. In some samplers the resolution is a fixed property of the A/Dconverter,
but other samplers allow the user to set the resolution value to obtain a dirty, artificial and
"industrial" sound
Transposition
Once the waveform has been sampled and stored in memory, we need to be able to reverse the process to play
back the sample. This time the stored values are read out from the memory and the original waveform is thus
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ecreated.
The circuit reading the samples from the memory and converting them to sounds is called the "digital-to-analog
converter", or D/A-converter. Just as the A/D converter, this circuit is also controlled by a clock. For each tick of
the clock, a new sample point is read out and added to the waveform. The speed of the clock controlling the
D/A-converter is called the "readout rate".
If the readout rate is set to the same rate as the sample was recorded, the result is an exact reproduction of the
original sound source - or as exact as the sampling frequency and sampling resolution used for the recording
process will allow. But we can also choose to change the readout rate to achieve a pitch change, or
transposition. If we increase the readout rate, it will be just like playing a tape with higher speed - the sound
will have a higher pitch. If we instead read the samples at a slower rate, the pitch will drop.
This method is often used to map the sampled sound over the keyboard and thus creating a playable sound. By
doubling the readout rate, the pitch of the sound will be exactly one octave above its original value.
Another transposition method is "skipping" some of the sample points while playing back a sampled sound, and
thereby speeding up the playback rate. By skipping every other sample value, we in fact raise the sound with
one octave. To lower a sample beyond its original pitch, new artificial values need to be added between two
sampled values. We can lower the sound with one octave by simply retrieving each sample point twice.
Multisampling
Unfortunately we can't just take one sampled sound and transpose it over the whole keyboard range. As we
increase the sample readout rate, we will notice that not only the pitch will rise, but the sound will also become
very weird and "chipmunk-like". And at the opposite side, an artificially lowered sound will start to break up and
distort just a few notes below the normal pitch.
To avoid this, we can use a technique called multisampling. Instead of using just one sample over the whole
keyboard range, we use several different samples with different pitches, and combine these to cover the
playable range. We could instance sample a C3 note, a E3 note and an A3 note to cover one octave. Now we
don't have to force one individual sample to stretch further than just a few notes.
If we wish, we can use a different sample for each key on the keyboard, but quite often we can get away with
as few as five or six different samples. To further enhance the playability of our sampled sounds, we can even
assign different sets of samples to be played depending on how hard or soft we strike a key on the keyboard.
Such a map of samples is usually called a program.
Editing
Once a sound has been digitized and resides inside our computer or sampler, we can manipulate and change it
in an almost infinite number of ways. By using a computer, we can visualize the sample and edit it almost any
way we like. Samples can be time-stretched, cut, shortened, reversed, flanged and twisted to create completely
new and astonishing sounds.
One of the most useful editing functions is the "loop" function. Looping a sound means that a small part of the
sampled sound is played repeatedly over and over again. By using a clever loop, a short sample of e.g. a violin
sound can be stretched out to last as long as we hold down the key. A benefit of the loop function is of course
the saving of precious sample memory.
But there is nothing to stop us from sampling whole bars of music. We can in fact rip off drum patterns, vocal
chords, guitar riffs or cool grooves from our favorite album and loop it to use them in our own music. Ethically
this might of course be highly doubtful and since we're most likely infringing on copyrighted material, it can
even involve legal aspects.
Playback modules
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Sampling is an art - it is very hard to create musically useful samples. To create a good multisample of a string
ensemble, we would first and foremost need to have a real string ensemble at our disposal - not very likely, is
it?
Fortunately we can let others do the job for us - we can for instance purchase third party sample-CD's and CD-
ROM's. But there are also a large number of synthesizer instruments, which already come fully loaded with
hundreds of crisp and clear 16-bit stereo multisamples from the factory.
These instruments are usually called sample-based or PCM-based instruments, which means that their sound
relies completely on the samples onboard. They can't sample new sounds, but instead they use these prefab
samples as their internal waveforms.
The problem with this technology is that the sound palette of these instruments is rather limited. Even if they
sometimes are expandable with new sound-cards, basically we are stuck with the sounds provided by the
manufacturer. While this may not be a concern for a country-band keyboard player, a highly realistic soprano
sax may not be of any value to the new-age synthesist.
MIDI
In the early 80's, every synthesizer manufacturer had their own standards on how to control their synthesizers
remotely. Two Moog synthesizers could for instance quite easily be linked together, but if you wanted to connect
an Oberheim OBX-a synthesizer to an ARP 2600 synthesizer, you were in trouble: the two synthesizers used
totally different control signals and different voltage ranges.
To remedy this problem, some of the leading synthesizer manufacturers decided upon a standardized set of
signals, that would allow a more flexible communication between different synthesizer models. This standard
was named MIDI, which is an acronym for Musical Instrument Digital Interface. It is a standardized language by
which electronic instruments and computers can communicate and exchange information with each other,
regardless of make or model.
Connecting several synthesizers to form a network can be very useful for many reasons - for instance, we may
wish to control more than one synthesizer remotely by using only one keyboard. But the most useful and most
common application of MIDI is the recording and editing of an entire composition with a MIDI sequencer or
equivalent software.
We will speak more about this in a moment, but let us first take a closer look at MIDI. What kind of information
is handled by MIDI? Let's illustrate this with an example:
Say that we press down a key on a MIDI synthesizer. Besides the obvious fact that the synthesizer produces a
note, it will also generate a MIDI signal. This signal looks something like this:
NoteOn-60-127
For a synthesizer or computer the message is plain and clear:
Depress the middle C key on the keyboard
with maximum velocity
It's important to understand that this signal has nothing to do with the sound itself. It doesn't state anything
about if the sound is supposed to be a flute or a snare drum sound. You cannot process the MIDI signal like
audio signals, such as adding a reverb to it.
The generated MIDI signal is now transmitted through the MIDI Output jack on the back of the synthesizer. If
this output jack is connected with a cable to another synthesizer, the signal will travel through the cable and
into the second synthesizer. This second synthesizer in turn will recognize the incoming signal and will respond
accordingly. It will also produce a note - just like as if you had played its own keyboard.
In such a setup, the first synthesizer is usually called the "master", and the second synthesizer is called the
"slave".
13

The slave synthesizer will now also "pass", or "echo" the signal further into the next connected synthesizer via
its MIDI Thru jack. The signal will thus travel all the way to the end of the MIDI chain and all connected
synthesizers will play the same tone.
When you release the key, another MIDI message is created:
Release the middle C key.
Until this message arrives, the slave synthesizer will keep on playing the note.
Here's a little experiment for you to try: depress a key on the master keyboard, and then unplug the MIDI cable
before you release the key! What happens?
You guessed it - the release command will never arrive to the slave synthesizer, resulting in an endlessly
playing tone. This dreaded syndrome is called the "MIDI drone" - pretty scary in a live gig situation! Sometimes
the only way to shut off the orphaned tone is to turn the slave synthesizer off and on again.
Not just note events, but almost every event that you create on a keyboard will be transmitted like this - pitch
bend, after-touch or program change events.
Most MIDI commands, such as the Note On commands we looked at so far, can be understood by any
synthesizer, regardless of model. You can for instance control a Korg X3 synthesizer from a Kawai K4
synthesizer. But there are also some MIDI commands which are specific for a certain type of synthesizer. These
describe the setting of each individual parameter that creates a patch for that synthesizer model. These
commands are called "System Exclusive" and are used by synthesizer program editor software.
It is impossible to give all the details about every MIDI command in this limited space, so we will not go further
into the technical aspects of MIDI.
General MIDI
The original MIDI standard has some major limitations. We have already bumped into one of them: a MIDI
signal doesn't tell us anything about which instrument sound that is supposed to play a specific note.
For example, if the composer had selected patch number 5 for channel 1, intending this to be a piano sound, but
the synthesizer playing the MIDI data had a tuba sound mapped to patch number 5, then the notes intended for
the piano would be played by the tuba - even though this synthesizer may have an excellent piano sound
available at some other patch number.
To get around this problem, the General MIDI (GM) standard was created. This standard assigns certain
memory locations to different families of sounds. Piano sounds are for instance assigned to memory banks 1 - 8,
chromatic percussion to 9 - 16, organ-type sounds to 17 - 24 and so on. By using this standard, you can be
assured that your string ensemble parts will be played back by a string ensemble sound and not by the
14

accordion or the didgeridoo (even though it may probably sound pretty hilarious).
Of course this may not be a problem if you're composing music for your own synthesizer setup, in which case
you don't have to bother about where you save your sounds. But if you're composing music for computer games
for instance, it's nice to know that your music will sound as intended regardless of which soundcard that will be
used for playback, as long as it is GM-compatible.
MIDI channels
With a little imagination it should be quite obvious, that if we make a chronological list of all the Note On and
Note Off commands that make up a musical piece, we have in fact a detailed description on how to play this
piece of music on the keyboard. Such a list of MIDI events is usually called a MIDI sequence, and a device or
computer software used to record and playback such a sequence is called a MIDI sequencer.
But wait a moment: a musical piece usually consists of more than one part - we may for instance have a
synthesizer playing a bass part, another synthesizer playing a piano part and a third synthesizer playing a string
part. How can we achieve this simultaneous multiple-part playback in a MIDI sequence without all the
synthesizers playing the same notes in unison?
The answer is, by using different MIDI Channels.
Every MIDI command is "tagged" with a channel number from 1 to 16. This means that you can for instance
simultaneously send a "C Note On" command on channel 1, an "E Note On" on channel 2 and a "Program
Change" command on channel 3.
If you have one synthesizer tuned in on channel 1, a second synth on channel 2 and a third on channel 3, then
each synthesizer will only respond to incoming MIDI information on their specific channel and ignore everything
else. The first synth will thus play the C note, the second synth the E note and the third will perform the
requested program change.
A MIDI cable can carry information on 16 different MIDI channels at once, which means that we can have 16
synthesizers responding to each of their specific parts.
We can record the bass part on channel 1 into a MIDI sequencer, and then overdub the piano part on channel
two and the string part on channel three. We can continue until the whole composition is complete or until we
reach the 16 channel limitation. When we wish, we can play back all the different channels simultaneously. It
will sound just like if we had sixteen musicians playing their synthesizers.
Fortunately we don't have to hook up sixteen synthesizers if we want to create a 16-part musical arrangement.
Many synthesizers can receive MIDI-data on several different channels at once, just like if they had several
separate synthesizers inside their shell. Such synthesizers can for instance play strings, bass, drums and piano
at the same time. If you have read the chapter about synthesizer voices, you should remember that the ability
to play several different sounds at once is called "multi-timbrality".
Sequencing
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If you have read these chapters in a succession, you should already have a fairly good picture of what MIDI
sequencers really are. But let us now look at these things in a little more detail!
The idea of automated music is not a new one - self-playing pianos were for instance quite popular at the
beginning of the century. But when we speak about sequencers, we are usually referring to electronic devices
used to trigger automated notes on a synthesizer.
The first simple sequencers could trigger eight or
sixteen notes in succession.
The programming was done with switches and buttons,
and the data was stored as electric signals. These
signals could then be fed into a synthesizer - which then
played back the corresponding tones.
Click on the icon to listen to a typical sequencerpattern!
(106 kB)
(The synthesizer you hear is an RB-338.)
Korg SQ-10 Analog Sequencer
Sequencers were most often used to create very precise, repeating eight- or sixteen-note bassline patterns, just
as can be heard in the example above. Several new-age groups, such as Tangerine Dream used these simple,
yet hypnotic patterns as a foundation on which their compositions were based.
Some years later the first microprocessor-controlled sequencers were manufactured. These could store several
hundred notes - actually whole musical pieces.
When MIDI soon thereafter became the worldwide standard for communication between electronic musical
instruments, a whole new world of possibilities opened up. The new MIDI-sequencers could store and handle an
almost unlimited amount of MIDI data.
We have already stated that a MIDI sequence is in fact a chronological list of MIDI events. It is all the different
Note On and Note Off commands that make up a part in a musical piece.
It is very important to keep in mind that a MIDI sequencer does not record the actual sounds, but only the MIDI
events, such as Note On and Note Off commands. You will need to have a synthesizer connected to the
sequencer to hear the result.
It's worth noting that some synthesizers are also equipped with built-in sequencers. Some of these are rather
crude composition tools, capable of storing a hundred notes, while some others feature full multitrack recording
and editing of a hundred thousand notes and MIDI events.
Modern sequencers, such as the Roland MC-80 in the picture below, are in fact nothing less than dedicated
music computers.
If you wish, you can still enter the individual
notes and rests using the same, somewhat
rigid "step-mode" as in the first analog
sequencers.
While this mode may be very useful for
entering mechanical sounding or very strict
rhythmic musical patterns, a far more
common approach is to use modern
sequencers as real-time multi-track MIDIrecorders.
Roland MC-80 MicroComposer
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By connecting a MIDI-keyboard to the sequencer, you can just play your parts, and let the sequencer record
and store your every move. The sequencer can then replay all the phrases and parts, exactly the same way as
you played them. The recorded data can also be overdubbed, edited and manipulated in almost any way you
like.
Today, dedicated hardwired MIDI sequencers have almost completely been replaced by computer software. We
shall look at these in the next chapter.
Local control
A keyboard synthesizer has two distinct parts: the keyboard itself and the synthesizer circuits inside the shell
that actually produce the sounds.
When played, the keyboard triggers the synthesizer circuits and sends out MIDI messages. But if we wish, we
can separate the keyboard from the sound generating circuits. This is called Local Control and can be set either
from an instrument's front panel or via an incoming MIDI message.
When the synthesizer is in "Local Control Off"-mode, the keyboard will continue to send out MIDI data when
played, but it no longer triggers sounds directly from its own synthesizer circuits. At the same time, the
synthesizer section will continue to respond to incoming MIDI messages while ignoring the attached keyboard.
The keyboard can send on one MIDI channel, while the synthesizer responds to another. This is especially useful
for MIDI recording work, when only the sequencer should be triggering the synthesizer while you record new
parts for other instruments in the studio.
The illustration below shows a typical MIDI setup. A master keyboard synthesizer is used to enter the MIDI data
for all parts into a sequencer. The sequencer in turn controls three slave synthesizers. All synthesizers are
connected in one MIDI chain, but they only respond to their specific MIDI channels and ignore everything else.
As you can see, the last synthesizer in the chain is the same keyboard you use to enter your parts. This synth is
now both used as a MIDI "keyboard" and a "sound module", and so it must be operating in "Local Off" mode.
Now, just for the experiment's sake, let's set the Local Control of the master synth to On. What happens now?
Well, as we play a key on the master keyboard, a note is generated. But the corresponding MIDI signal is also
sent into the sequencer, and echoed through all the three slave synths. Finally the signal will arrive back to the
master synth - which then of course will play the very same note one more time, just a fraction of a second
after the key depression. The result is a strange, doubled, "flanged" sound, most audible with short, staccatotype
of sounds, such as drum sounds. The polyphony of the master synth will also be halved, since each key
depression now triggers two sound circuits at once.
17

Master keyboards and sound modules
To enter data into a MIDI sequencer, we need some kind of input device. Of course we can use any MIDIequipped
synthesizer to do this, but there are in fact some keyboards which don't have any internal sound
sources at all - instead of making sounds, they only generate MIDI signals when you play their keyboard. These
keyboards are usually called master keyboards or just keyboard controllers.
Roland PC-180 Keyboard Controller
At first glance, a master keyboard might look like just another synthesizer, but you would soon see that the
programming buttons are missing, and so are the audio output jacks on the back of the unit. Some master
keyboards are designed to be small and convenient units to be used together with personal computers, such as
the Roland PC-180 in the picture above. More professional keyboard controllers are equipped with a full 88-key
weighted piano-style keyboard, instead of the regular 61-key keyboard found on most synthesizers.
Just as there are soundless keyboards, there are also keyboardless synthesizers. Such synthesizers are usually
called sound modules, MIDI modules or just simply modules.
Their function is very simple: they listen for incoming MIDI signals, and play them as they arrive. Having no
keyboards, obviously you can't play these modules directly. Instead you must use an external MIDI keyboard, or
let the module play back the prerecorded data on a MIDI sequencer track.
Roland SoundCanvas 8850
The reason for using such modules instead of keyboard-equipped synthesizers is of course to save space - five
or ten such modules can easily be fitted into a rack, not much larger than a normal sized home stereo rack. And
naturally the price is often much lower. But don't be mislead about their modest sizes though - they're just like
any other synthesizer.
Many synthesizers come in both a regular keyboard-equipped version, and also a module version. For instance
the Roland D-50 synthesizer has a module version called the Roland D-550.
The Roland D-50 keyboard...
18

... and the Roland D-550 module
But some modules are even smaller than that: they are only electronic cards residing inside a personal
computer. Usually we don't refer to these as "synthesizers", but as "wavetable sound cards".
Computers
No matter what kind of music we are creating, computers are without doubt the most powerful tools for
composing and creating music ever - and certainly not only for electronic music. So, what is needed for
computer aided music composition?
Apple iMac running Cubase VST
First of all we need a computer, of course.
Almost any half-decent personal computer can
handle the task of MIDI recording and processing
with the greatest ease. Recorded MIDI-data also
takes up very little space on the hard-drive.
As long as we only work with raw MIDI-data - and
not audio - we really don't need the latest and
fastest computer hardware available.
But to enter the MIDI data in a some way, we need some kind of input device - usually a MIDI keyboard or
synthesizer. These piano-like keyboards are the most natural and convenient input devices: anything we play on
the keyboard is translated into MIDI data. If you remember, we have already looked at these keyboard
controllers in a previous chapter about MIDI sequencing.
Now we want these commands to be transferred into the computer, where they can be edited, stored and
played back. But since most computers don't have built-in MIDI-jacks, we must use some kind of MIDIinterface.
Roland UM-4 MIDI-Interface
MIDI-interfaces come in various shapes and sizes. Some are internal cards, which need to be inserted in an
available PCI or ISA slot inside your computer. Others are standalone units, which are plugged into the printer
port on the back of the computer. The most modern interfaces use the USB-standard, which further simplifies
the communication issues between electronic music equipment and computers.
Finally, we need a suitable MIDI-software running in the computer - and we're all set!
19

Music software
There are many different computer programs designed for the purpose of MIDI-recording and editing. These
programs are sometimes called MIDI-sequencers, but they are much more than that - they are in fact music
composition and production systems.
MIDI software is the musical equivalent of word processing software - of course instead of letters and words
they handle MIDI-data. Then data can be displayed in many different ways - like diagrams...
... events in a list...
... or as musical score.
20

Software-based sequencers are probably the best composition tools ever made. You can record your musical
parts either in real time or by programming the individual MIDI events by hand. Once you are happy with a
part, you can keep on adding other parts until you are satisfied with your composition.
You can cut, paste, copy and edit the parts in any way you like. You can correct bum notes, change the velocity
for individual notes and move them around as you please. You can at any time change the tempo and the tuning
of the whole composition, or just some parts of it.
The possibilities are nearly endless: you can for instance record a number of alternative solos, riffs or
arrangements in separate tracks, and then keep the one you are most happy with. Most modern sequencers can
also implement some slight imperfections and timing inaccuracies for the recorded material to sound more
"human". There are semi-intelligent composition algorithms that will create musical sequences or phrases of a
simple chord to suit a selected musical mood and style.
You can even invite a guest musician on the other side of the world to record his own parts and send it over to
you to be imported in your compositions.
Audio
With today's most sophisticated MIDI-recording software (such as Steinberg Cubase VST and Cakewalk Audio),
the border between MIDI and audio (sounds) are starting to get more blurred than ever. You can for instance
set some of the sequencer tracks to contain regular MIDI data, while other tracks can contain digitally recorded
sonic material, such as singing or acoustic instruments.
Cubase VST Arrange Window
With such programs you can in fact turn your personal computer into a full-fledged digital recording studio.
Features such as direct-to-disk recording that only a decade ago were only available in the most advanced
music studios in the world, are suddenly within the reach of most of us.
Running a complex sound processing software is probably the most demanding task your computer will ever
face. You can never have enough memory, processor capacity or hard disk space. But a decent home computer
(minimum 450 MHz Pentium II or G3, 128 MB RAM, a fast hard-disk and a good 16-bit soundcard) can be used
to record audio data, play back multiple channels of digital audio, and apply effects or equalization in real-time -
a similar concept to that of traditional analog recording studio technology in fact!
As an example, the new version of Steinberg Cubase VST 5.0 can record and play back up to 128 separate CDquality
digital audio tracks in 32-bit resolution stereo within a virtual studio equipment, complete with digital
equalizers and effect processor modules, such as echo or reverb.
21

Virtual Effects Rack in VST
This is all performed in a completely open-ended system
allowing the users to add modules such as synthesizers,
vocoders or fuzz-boxes while never leaving the digital
domain.
These modules are simply installed with a few mouseclicks
- no cables required!
Finally all you need is a CD-burner to start creating your own records with your own music for distribution!
Software-synthesizers
Computers have evolved a great deal from the days when their sonic capacity was all about tiny electronic
beeps and noises. Almost all modern 16-bit sound cards are capable of creating highly complex sounds. Many
sound cards can also be used as regular synthesizers on their own.
They can often create sound by either "frequency modulation" (FM) or by "wavetable synthesis". The first
method is a purely synthetic method, and the latter a sample based method, where the sounds are based on
real live samples of acoustic sounds.
With the introduction of higher-performance personal computers, you can use the main CPU of your computer
together with a decent sound-card to perform music synthesis, rather than depending on dedicated hardware.
For a computer with sufficient processing power, such a software synthesizer can match or beat the functionality
and sound quality of many dedicated hardware synthesizers. There are numerous software synthesizers
available today, such as the VAZ Modular, the ReBirth RB-338 or the new stunning Reason.
All this is made possible by the increased power of today's standard personal computers. What previously
required an investment of hundreds of thousands of dollars can now be realized with a couple of thousands! This
revolutionary music technology is available for anyone today, and the only limitation to what can be achieved is
your own imagination.
Drum machines
A drum machine is very much like any synthesizer. The main difference is that while a synthesizer is a generic
musical instrument, drum machines are dedicated to create drum and percussion sounds.
Instead of piano style keys, drum machines are usually
equipped with touch sensitive pads, which you can hit
with your fingers, or even with drumsticks.
The drum sounds are usually samples of real percussion
instruments, like bass drum, snare drum, toms and
cymbals.
Casio RZ-1 Drum Machine
Of course it is not very easy to play complete drum parts by tapping with your fingers in time. Drum machines
are therefore almost always equipped with built in sequencers. With the sequencer, you can program rhythm
patterns and append these into songs. A pattern is often just one bar of rhythm, while a song is a complete
composition.
The era of drum machines seemed to be over just a year ago. Modern synthesizers and samplers are capable of
creating the most exquisite drum sounds. With the aid of computers, music software and samplers, musicians
can even use complete and intricate rhythm loops in their compositions.
But now it seems more likely that the drum machine will continue to survive in a new shape, mostly aimed
towards dance-oriented music.
22

Click on the icon to listen to a modern drum
machine loop! (93 kB)
(The drum machine you hear is the Korg ER-1
featured below.)
Korg ER-1 Rhythm Synthesizer
Mixers and effects
One good example of a modern drum machine is the Korg
ER-1 Electribe Rhythm Synthesizer, featuring excellent
and modern percussive sounds in combination with
superior real-time expressiveness.
The sounds can be tweaked and reshaped during
playback, allowing a much higher degree of
responsiveness than what's possible with music
workstations and samplers.
When using synthesizers in your music, you will sooner or later get involved with a certain amount of studio
technology, whether you like it or not. Even if this subject falls slightly outside the scope of these web pages, I
feel it to be necessary to include some basic information about home studio recording equipment and
techniques.
Since a synthesizer has no built-in speakers, to hear what you're playing you will either have to use
headphones, or you will need to plug it into some kind of sound reinforcement equipment.
Most synthesizers usually have two audio outputs - a left and a right output jack. These two has to be plugged
into the corresponding left and right input jacks of an amplifier, such as the regular home stereo amplifier. Its
really not that different from plugging a CD-player into your home stereo rack.
The same thing applies if you wish to record what you're playing - just plug the cords from the synthesizer into
the left and right input jacks of your tape deck or recording equipment.
But sooner or later you may face a problem: let's say that you buy a second synthesizer and want to be able to
play and record the sound of both of them simultaneously. What can you do?
The solution is of course very simple: you will need to use a mixer. A mixer in its most basic form is a device
that will take a number of inputs and mix these to a few outputs - often just a stereo output.
23

A synthesizer and two sound modules
being mixed to a stereo output
Audio mixers come in a huge variety of forms, shapes, sizes and prices. Let's see what's common for them!
A property for every mixer, is the number of channels the mixer can handle. A channel is simply the number of
separate audio lines that can be mixed together. If you have two synthesizers, with one left and one right
output each, then you will need four channels to be able to mix them. The simplest keyboard mixers have four
channels, while complex studio mixer consoles can have as many as 64 channels and more.
Tascam TM-D8000 40-Channel Digital Mixer
How many channels you need depends on how many sound modules and synthesizers you intend to hook up in
your studio simultaneously. For a normal home studio consisting of a couple of synthesizers, a simple, rackmounted
16-channel line mixer is a good choice. It will allow you to grow along with it without forcing you to
mortgage your house.
A mixer has usually a plethora of knobs and buttons. But don't let the sheer number of knobs intimidate you:
most of the buttons and sliders are repeated for each channel.
The most prominent parts of the mixer console are the following:
• Fader
• Panpot
• Equalizer
• Aux send and return
Let's look at these in turn!
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The faders
The sound volume for each channel is controlled with
sliders, usually called faders. By moving a fader
upward, we increase the sound volume for the sound on
that channel and by sliding the fader all the way to the
bottom, we eliminate all the sound for that channel.
On some keyboard mixers the faders are labeled "Gain", but their function is the same.
Most mixers also have a button to mute the whole channel, thus instantly eliminating the sound from that
channel. As soon as there is no intended sound from a certain input, it should be muted to eliminate every
single trace of background noise and electric hum generated by cables and synthesizers.
Many mixers can also solo a channel, so you only hear the sound on this channel.
The output from the mixer is controlled by a pair of master faders, which control the sound volume for all the
channels at once. For instance, by slowly sliding the master faders to the bottom, you create a fade-out, without
affecting the relative sound levels for each of the individual channels.
Pan
In a mix, you will want to be able to position all the sounds in the stereo field - left, right or somewhere in
between. This is usually called the panning of the sound, and is controlled with a dial on the mixer, appropriately
labeled "Pan".
The pan control is similar to the balance knob on a
home stereo. In practice, this makes it possible to
simulate the original location of each performer in the
finished stereo mix.
When you plug in a stereo synthesizer in your mixer, you usually use up two channels: one channel for the left
output of the synthesizer, and one channel for the right. If you wish to retain the stereo field of the synthesizer,
you must set the pan of the first channel to the extreme left, and the other channel to the extreme right.
A good mix has an even balance between left and right. Putting all the drums to the left and all the voices to the
right be sound pretty funny, but is most often not a very good mix.
Sometimes you may want a certain sound to keep moving from the left to right in the stereo field. This is done
by turning the Pan knob from the extreme left to the extreme right and back.
Equalizer
The equalizer (or EQ) controls the "brightness" of the sound on the individual channels.
It's really the same as the Bass and Treble knobs on a regular
home stereo, only more precise and more exact.
The standard equalizer settings are high, middle, and low, but on
some mixers you may find other combinations as well.
25

Keyboards and synthesizers are usually not in the same need for an equalizer section as other instruments, and
so on some other keyboard mixers the equalizer section may have been completely left out. This is often also
done in order to keep the price down - and also the background noise level.
Effects
Quite often you may wish to do more with your sounds than just adjusting their relative volumes, filtering them
and positioning them in the stereo field. For instance you may want to add some bouncy echo effects to some
sounds and make other sounds appear to be playing in a huge cathedral.
Sound processing is called effects in electronic music terms. Until quite recently, effects required a substantial
amount of additional hardware to be plugged into the mixer.
Roland SRV-330 Dimensional Space Reverb
Today most of these effects are available as a piece of software which can be set to process a sound file in your
computer or the sound input in real-time.
The unprocessed sound is called the dry sound. The dry sound is sent into the effects unit which processes the
sound and returns the result to the mixer. This is called the effects loop.
The jacks on the mixer which we use for this are called aux send and aux return, and they are controlled by
dials on the mixer panel. When we increase the amount of "aux send" on a certain channel, then more of the
sound on the channel is sent to the effects unit. When we increase the amount of "aux return", we increase the
amount of processed sound.
There are hundreds of different sounding effects to choose from. It's impossible to describe every variant and
it's usefulness for a certain situation, and often it is enough if you are familiar with a few of the most useful
effects, such as reverb, delay and chorus.
Here are few of the most commonly used effects in an electronic music studio.
Every effect is illustrated with a four-bar sequence played on a simple synthesizer sound and a drum machine
sound. The first two bars are completely "dry", and the other bars are processed with an effect box.
Headphones are strongly recommended for these sound examples!
Reverb Creates an ambience or a "space" around your sound, ranging from a middle
sized shoebox to a gigantic cathedral. Reverb is definitely the most important
effect you will ever find! This example simulates the characteristics of a large
room. Just listen to the sound pattern become three-dimensional!
Echo Sometimes called digital delay or just delay, this effect creates a repeating echo
26

pattern. The echoes can be set to either side of the stereo field, or they may
bounce from one side to another.
Chorus Generally used for creating a sense of wide stereophonic or "thick" sound or, as
in this example, a slightly metallic, "bottled" sound.
Flanger Creates a very interesting "moving" or "sliding" sound. Very hard to describe, so
listen to the example file instead!
Phaser Phasing also creates a very interesting sound, also hard to describe in words.
You'd better try to figure out by yourself - this is stereo phasing at its best!
Distortion Creates a clipped and rather unnatural sound. Most often used on electric guitars,
but the effect works just as well on other sounds as well. Listen to how the rather
weak-sounding bass drum turns into a brutal "hardcore" kick!
Some effects boxes are designed for one specific purpose, like chorus. Others can create more than one effect.
The most recent processors can even create more than one effect at the same time. These multi-effect
processors can for instance add a combination of reverb and delay to the sound.
I would recommend using a dedicated effect box for the most common effects, such as reverb, and use multieffect
processors for other effects. This way you can get the best out of the reverb box and free up the multieffect
box to do other things.
Buyer's guide
So, you've made up your mind about purchasing a synthesizer and pursuing a great career of composing and
playing music. With a nice, fat wallet in your pocket you stroll away to your local keyboard shop, whistling a
merry tune. What happens next?
If you already know what you're looking for, you're lucky. You just point at the target of your desire and exclaim
- loud enough to let all the other envious customers hear you - "I would like to have one of those, please - ah,
by the way, make that two!"
Does it sound like you? Really? I told you, you're lucky.
If you're not so lucky, the very instant you step into the shop, a smiling salesdroid, immediately spotting your
hesitation, will approach, muttering "come here little boy, have a cigar". Before you know it he will be talking
about ROM and RAM, PCM and MIDI, Voices and Programs, Polyphony and Expandability, Tracks and Channels,
confusing you totally.
He might also start playing on a master keyboard or two, making some incredibly complex noises and musical
phrases while he keeps on talking about some remote controller gadget and a touch sensitive screen. You're
impressed, but you're not even certain about which instrument he is talking about.
What's worse, he will inevitably tell you that the only synthesizer that you are vaguely familiar with is a
helplessly outdated one, long time ago replaced by a new, improved - and of course significantly more
expensive one.
Define your needs
First of all, you need to decide about your needs. Obviously this will depend on what you wish to achieve - the
requirements of the keyboard player in a country band will be quite different from the ones of a professional
movie soundtrack composer or the ones of a teenage bedroom techno wannabee. Make a list about what's
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important to you. Solid drum sounds? Realistic piano? Synthetic techno-noises?
Do you need 88 fully weighted wooden keys or are you happy with a standard 5 octave synthesizer keyboard?
And also if you already have a good solid MIDI keyboard, maybe you should consider purchasing a keyboardless
synth module as your second synth. I know, modules can be a hassle - they're stuck in the rack - but if studio
space is at premium, like if your home studio is located in your apartment, rack modules can be godsent.
Perhaps you're not very interested in actually playing a keyboard instrument, but would rather like to assemble
more or less prefabricated rhythms, loops and sequences to a dancey tune? In that case maybe you should
consider purchasing a groove box?
Make up your mind in advance about how much money you are willing to part from. It's easy to overstep your
boundaries. Just like you would expect, there is no upper limit. The most complex musical instrument setups
cost more than your house and only the likes of Peter Gabriel and Jean-Michel Jarre can afford them. But what's
more important is to avoid the "crappy synth threshold" (CST), a level below which you should avoid getting.
Don't aim too low
Below the CST you will find synthesizers in which serious sacrifices had to be made to keep the price down - like
a lousy keyboard, lack of important functions or a limited palette of sounds. A synth from below the CST will
entertain you for many weeks - even months, but eventually you will find that it stops you from developing your
musical ideas and you will be looking for something new.
So, where is this CST? Well, it's hard to say, but if you stay above the 1000-dollar level, you should be fairly
clear.
Please understand me correctly - I don't say that you can't find the synth of your dreams for much less, but you
should definitely watch out for anything cheaper than, say 600 dollars. Even in otherwise absolutely brilliant
designs, like the Korg Electribe-series dance tools you will have to live with compromises, like the lack of a
proper keyboard.
Try it out
The most important is to use your ears. Kindly tell the salesdroid to give you a pair of headphones and ask him
to go away. Plug the headphones into the phone output jack of the synth - and not the phone output of the
mixer console. You want to know what the synth really sounds like, without the sound first taking a trip through
that two-grand aural sound processor unit, right?
Listen. Really. What does it sound like? It's very easy to be overwhelmed by any new sound, but try not to be.
Step through the programs and use your ears. Focus on those sounds that suit your musical preferences. All
those looping sounds and whirling noises may sound very impressing at the shop - but honestly, how likely is it
that you will ever use them in your music? Not very much, is it? Also don't play that demo song - it will just give
you the wrong impression. Some instruments are also known to be cheating, and feature additional effects and
sounds that you will not be able to recreate outside the demo.
When you have a feeling for the sounds, try another synth - at a completely different price bracket. Can you
hear the difference? What are the similarities? The differences? Take your time, this is actually quite important!
The good thing is that you can hardly go wrong. If you make sure to keep above the CST, almost every modern
synthesizer is a wonder of sounds and functions.
You could also decide to purchase second hand equipment by browsing newspaper ads and by frequent visits in
synthesizer shops. However there are some special considerations that need to be made when choosing this
approach. Read about them here!
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Sampled or synthetic
If you are into composing your own tunes or setting up whole arrangements you may want to look at
workstations. A workstation is basically a synthesizer with lots of polyphonic voices, equipped with a built in
sequencer, with effects units and with drum-kits. It's like buying a complete stereo hi-fi equipment with all
components integrated as opposite to purchasing each of the component separately.
The workstation approach is often a very economic and simple solution to get several important studio
components in one box. However, you should be warned that you will loose the individuality of your sound. If
you make a composition using only one certain workstation, it will be instantly recognizable. There is an evident
danger that your song will not sound like "you", but rather than "a Korg Trinity demo song".
Why? Many of these workstations are sample-based. This means that the internal sounds are all based on reallife
samples of acoustic instruments. This approach will undoubtedly yield the most realistic sounding imitations
of acoustic instruments - pianos, guitars, strings, drums or whatever. However, even if you select a samplebased
instrument with as much as 8 or 16 megabytes of onboard samples, its soundscape horizon is not
endless.
Another thing which you should keep in mind that most workstations are aimed towards popular and jazz music,
and the selection of the sounds usually reflects this. Most often you will find sounds which are usable for this
kind of music - like pianos, guitars, basses, brasses and strings. Usually not the kind of sounds you need for
speed garage or drum 'n' bass.
If you feel that this could be a problem for you, then you should definitely look for expandability. Many
instruments offer new samples by using added PCM-cards (cards with new sound samples), but remember that
these cards are often very expensive and can be hard to find a few years from now.
Mainstream workstations are hardly the new-age composer's dream machines. Also, if you are heavily into
techno dance-tracks, you may for instance not need a realistic soprano sax, but much rather prefer buzzing,
resonant basses and overdriven hardcore drum loops.
A far better solution is to use synthesizers which create their sounds by other methods. Even if surprisingly
realistic sounds can be achieved by a non-sample based instrument too, the real fortι of a true synthesizer are
those completely new sounds, the ones resembling nothing else in the world except for those early 80's
synthesizer sounds - filter sweeps, self oscillating sounds and morphing noises. Synthesizers like the Nord Lead
should suit your needs a lot better.
What do you do if you want both realistic sounds and more high-tech sounds? There are many synthesizers
capable of creating both purely synthetic and also acoustic-sounding timbres (like the Korg Wavestation SR),
but the obvious answer is to get more than one synth.
Chances are that you will end up with several different synths anyway. I might just as well warn you right now,
so you can get prepared for it. Why is that? Well, simply because one synth is good at acoustic sounds, another
at techno-sounds and the third at ethnic noises. It's little point in having four Alesis QS7's, but a nice variety of
instruments of different makes and generations, some sample-based and some pure synthetic ones can create a
versatile studio and a highly personal sound.
Samplers
The ultimate way to make your own world of sounds is to use sampling instruments. If you do techno dancetracks
then sampling is really your only choice. There is just no other method to create a better techno
soundscape.
A sampler takes any "real-world" sound, processes it and outputs it in a whole new way. A good entry-level
sampler, such as the Akai S01 can be quite useful as an addition to an existing synthesizer setup, but will not be
enough by itself in the long run - don't let anyone fool you into thinking otherwise.
Sampling requires a lot of memory and processing power, which makes it a very expensive technology. Even
though much has happened since the age of the Fairlight, a really good solid sampler equipped with a healthy
amount of memory (at least 8 MB) still costs way beyond 2000 dollars. But if you can afford it, look for hard
drive options (or SCSI interface) too - swapping floppy disks can be quite a tedious task!
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What about computers?
Personal computers are becoming more and more usual today as tools used for creating and recording music. As
the PC's are getting more powerful than ever, their usefulness for musical purposes is also steadily increasing. A
fast desktop computer equipped with a decent sound card, running some appropriate software (like Cubase VST,
Cakewalk Pro Audio or CoolEdit Pro) can in fact be used as a regular multichannel digital recording studio.
Computers can also be used as synthesizers on their own by running software "emulating" a dedicated hardware
synthesizer. These software synthesizers are quite usual today and their sound quality and functionality equals
those of regular, hardwired synthesizers.
To be able to play a soft-synth, you'll need a MIDI-keyboard connected to the computer. Also keep in mind that
if you wish to use one computer as both a soft-synth and to record audio, you may need two sound-cards, since
many soft-synths and recording software cannot use the same soundcard at the same time.
I don't find it unrealistic to think that dedicated hardware-synthesizers will in a soon future be replaced by
software based ones, just like the hardware based sequencers that have been rendered obsolete by MIDIprocessing
software. What the future has to offer can only be speculated upon, but one thing is certain: a new
era is dawning in the area of computer music, and a brand new world is being opened up for the public.
Buying used equipment
Say that you wish to build a small home studio. You don't really need all the latest equipment and your budget
is rather limited. What can you do?
Start by asking yourself the following question: is a synthesizer, which was the state of the art just a few years
ago, merely a pile of rubbish today? Of course not. You may not be able to create the most recent sounds from
the hit lists - but there are sounds on my 1986 Korg EX-8000, which I still can't reproduce on any other
machine.
Evidently there is a market for used equipment. How can you find second hand synthesizers?
Well, you can for instance check the newspaper for used gear. Keyboard magazines are the obvious ones.
Sometimes you can find true bargains, but you should always be prepared to examine the equipment before you
buy it. Once you take it away, your chances to sell it back in case of a malfunction are rather limited.
A better choice would be to pay your local keyboard shops a visit. Quite often they have demo synthesizers and
used equipment for sale. Of course their asking price is higher than the ones you'll find in the newspaper ads,
but they will almost always offer a limited warranty of say, three months. Quite enough for any odd problem to
make itself noticed.
Compare the prices - some owners don't seem to realize that electronic music equipment has a shorter life span
than cars or computers. Expect the price to have dropped to at least half the original price after two or three
years! Of course some classic, vintage instruments, like the MiniMoog, still hold on to their exclusive status and
corresponding price tag.
Things to check
For keyboards, check the action of each individual key. Are they sticking or is the action uneven? Listen for
strange noises from the keyboard - it can be a sign of wear. Check the action for velocity sensitivity and after
touch (if this applies). Make sure the joystick is working properly and that it springs back to the middle when
you release it.
Has the keyboard been dragged around on gigs without a protecting case - maybe even dropped once or twice?
Examine the shell carefully, even at the bottom. Scratches, bumps, tapes, scribblings or cracks may imply that
the inside can be damaged as well. Move the synth around a bit. Is there something loose on the inside? When
a broken-off resistor is rolling around inside the shell, something is bound to get more broken soon.
Leave the instrument on for five or ten minutes. Make sure that the power is not switching off by itself, that the
instrument does not create excess heat, doesn't begin to smell funny or - shock horror! - starts to smoke. Check
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the display for flickering when you play the keys - it could be a sign of a malfunctioning power supply.
Connections, like outputs, headphone jacks and pedal connections are prone to be broken. There is nothing
more annoying than discovering broken line outputs too late, just because you only tested the synth with your
headphones!
Check the MIDI connections. You will need to have another keyboard or a computer to perform this check, but a
broken MIDI circuit can render the instrument useless for sequencing work, so this check may very well be
worth some fuss.
If the synth is equipped with a disk drive, watch out! Old disk drives may be working perfectly for decades, but
when they break down you may not be able to replace them. Check the drive out for dust and dirt - use a
flashlight to see if there is grime and grease on the inside. I am serious. Take a look at the disks - if provided.
Do they look dirty? Are the labels loose or sticky? Do they have pencil writing on them? Pencil dust, combined
with eraser dust is the worst disk drive-killer you can imagine.
Definitely avoid instruments using QuickDisk (QD) drives, like the Akai S700, Akai X7000 and the Roland S10.
Empty QD-floppies used to be very expensive and they are almost impossible to get hold of today!
What about the manuals? You may be able to figure out the basic operation of the instrument by yourself, but
can you set up the System Exclusive Patch Dump Request too? The condition of the user manuals can also tell a
lot about the previous owner - a mint condition manual may tell you that the owner took good care of his
instrument.
Stolen equipment
How can you be certain that the equipment you wish to buy is not stolen?
Well, this one can be a bit tricky. If the previous owner can show a receipt of his purchase, then you are
probably quite safe. But otherwise you should be careful. Ask the seller about the reason for the sale. If the
price is absurdly low, or the conditions of the purchase seem weird, you should definitely watch out. Also check
that the serial number plate (often on the back of the synth) is intact. If this plate has been removed or
obviously replaced, you can be pretty sure that the instrument is a stolen one.
Sometimes it can be tempting to buy a synthesizer at a ridiculously low price with no questions asked, but you
should remember that buying stolen property is a crime! And if the police comes knocking on your door, you will
need to have some good explanations at hand! Losing your new synth, your money and getting sued at the
same time is more than enough to ruin your day!
Frequently asked questions
I receive a lot of mail about musical instruments and synthesizers, and it's great to be able to help. I try to
answer your questions if I can, but it may take some time!
Q: Which synthesizer should I buy?
A: Please, please, please - don't ask me what synthesizer you should buy!
This is without doubt the most frequently asked question and it is absolutely impossible for me to answer it!
As any newcomer in this area surely must have noticed, it's a complete jungle out there: there are thousands
and thousands of different kind of synthesizers and modules, so picking just the right one for you is nearly
impossible. I am only familiar with, like ten or twenty of them. You have to take your time and do your
homework, reading reviews in music magazines, gathering information, visiting music shops and trying out
the instruments that you feel good about.
For issues regarding buying synthesizers and music equipment, please check out my Synthesizer Buyer's
Guide web page. If you still have specific questions, don't hesitate mailing to me. I'll answer if I can!
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Q: Where can I get a manual for my synthesizer?
A: And this is definitely the second most often asked question.
I have no manuals for sale, and I don't have the time nor the money to make photocopies of my own
manuals. However, there is a company called RogueMusic (there are others I'm sure) from where you can
order manuals for almost any synthesizer to a reasonable price.
If your instrument is rather new, try contacting music shops or even the manufacturer of the instrument.
Q: What do I need for a PC-based studio?
A: For some generic guidelines, check out my chapter about PC-based studios. For more detailed specifications,
please contact your local music store - they can provide far better answers that I can.
Q: How can I find programs for my synthesizer?
A: Many music shops (and companies) sell third party ROM cards and discs for a lot of synthesizers and
samplers. You can also search on the Web (try AltaVista) and advertisements.
There are a lot of people who are looking for new sounds and would like to swap programs and patches if you
have an original setup of sounds for your synth. So that too is a good reason to take your time an create a
full bank of sounds yourself. It will most certainly be worth the effort!
Q: I would like to buy a DW-8000 synthesizer. Do you have one for sale and for how much?
A: I am not a retail seller and I don't normally have equipment for sale. But you can always give me an offer I
can't refuse... ;-)
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