WOOFER 12WS600 - jbl selenium

RESPONSE CURVES (0° AND 45°) IN A TEST ENCLOSURE INSIDE AN
ANECHOIC CHAMBER, 1 W / 1 m
110
100
POLAR RESPONSE CURVES
60°
30°
50 Hz
0
-6
-10
330°
300°
WOOFER
12WS600
60°
30°
100 Hz
0
-6
-10
250 Hz
-20
-20
-20
90° dB
270° 90° dB
270° 90° dB
270°
330°
300°
60°
30°
0
-6
-10
330°
300°
90
120°
240°
120°
240°
120°
240°
dB
80
150°
180°
210°
150°
180°
210°
150°
180°
210°
70
30°
500 Hz
0
-6
330°
30°
800 Hz
0
-6
330°
30°
1.25 kHz
0
-6
330°
60°
-10
300°
60°
-10
300°
60°
-10
300°
60
20 200
Hz
2k 20k
Response Curve at 0°.
Response Curve at 45°.
-20
90° dB
270°
120°
150°
180°
210°
240°
-20
90° dB
270°
120°
150°
180°
210°
240°
-20
90° dB
270°
120°
150°
180°
210°
240°
IMPEDANCE AND PHASE CURVES MEASURED IN FREE-AIR
400
90
30°
2 kHz 3.15 kHz
0
-6
330°
30°
0
-6
330°
60°
-10
300°
60°
-10
300°
300
45
-20
90° dB
270°
-20
90° dB
270°
ohms
200
0
degrees
120°
150°
180°
210°
240°
120°
150°
180°
210°
240°
Polar Response Curve.
100
-45
HARMONIC DISTORTION CURVES MEASURED AT 10% AES INPUT
POWER, 1 m
dB
140
120
100
0
-90
20 200 2k 20k
Hz
Impedance Curve.
Phase Curve.
80
HOW TO CHOOSE THE RIGHT AMPLIFIER
The power amplifier must be able to supply twice the RMS driver power. This
3 dB headroom is necessary to handle the peaks that are common to
musical programs. When the amplifier clips those peaks, high distortion
arises and this may damage the transducer due to excessive heat. The use
of compressors is a good practice to reduce music dynamics to safe levels.
FINDING VOICE COIL TEMPERATURE
It is very important to avoid maximum voice coil temperature. Since moving
coil resistance (R E) varies with temperature according to a well known law,
we can calculate the temperature inside the voice coil by measuring the
voice coil DC resistance:
T
B
T
A
R
R
B
A
1
T
1
25
25
T A , T B= voice coil temperatures in °C.
R A , R B= voice coil resistances at temperatures T A and T B, respectively.
= voice coil wire temperature coefficient at 25 °C.
POWER COMPRESSION
Voice coil resistance rises with temperature, which leads to efficiency
reduction. Therefore, if after doubling the applied electric power to the driver
we get a 2 dB rise in SPL instead of the expected 3 dB, we can say that
power compression equals 1 dB. An efficient cooling system to dissipate
voice coil heat is very important to reduce power compression.
A
60
20
200 2k
20k
Hz
Response Curve.
Distortion Curve, 2nd harmonic.
Distortion Curve, 3rd harmonic.
NON-LINEAR VOICE COIL PARAMETERS
Due to its close coupling with the magnetic assembly, the voice coil in
electrodynamic loudspeakers is a very non-linear circuit. Using the nonlinear
modeling parameters Krm, Kxm, Erm and Exm from an empirical
model, we can calculate voice coil impedance with good accuracy.
SUGGESTED PROJECTS
VB1205B1 VB1205D1 HB1205A1 HB1205A3 HB1205D1
For additional project suggestions, please access our website.
TEST ENCLOSURE
35-liter volume with a duct ø 3” by 1.97” length.
Devido aos avanços tecnológicos, reservamo-nos
o direito de inserir modificações sem prévio aviso.
Cód.: 28026133 Rev.: 00 - 01 / 06
www.selenium.com.br
www.seleniumloudspeakers.com