CLIOwin 6.5 PCI User's Manual - Audiomatica Srl

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10.4.4 PHASE & GROUP DELAY We used the term "Frequency Response" to refer to graphics the kind of Fig.10.5 and Fig.10.8. Frequency is in the x-axis in both figures. The units that respond to frequency, y-axis, are Volt and Ohm, respectively. Both of them are complex quantities (have real and imaginary part) and their magnitude is shown. Doing this we obtained a very useful piece of information but we lost the original data (infinite numbers of different real and imaginary part can lead to the same magnitude). How this information loss will affect your life depends on what you are going to do with these graphs, or, better, which was the original question you were trying to answer. Referring to Fig.10.5. A reasonable question could have been: how much does "A" filter attenuate signal at 100Hz in respect to 1kHz? You go trough the graph with the marker and answer 19.3dB. If you have the IEC 651 norm you can go to the "A" filter specs and you will find this attenuation should be 19.1dB +- 0.5dB for type 0 devices. End of your job. Lets now pose another question referring to Fig.10.8: how much a 10kHz tone would be attenuated if we wire a 10 ohm resistor in series with that woofer? We are simply not able to give the correct answer. We need another piece of information, which is PHASE. Fig.10.19 is the same measure of Fig.10.8 with phase curve overlaid. To obtain it we just stored the magnitude curve and clicked on the phase button. 150.0 CLIO 180.0 Ohm Deg 120.0 108.0 90.0 36.0 60.0 -36.0 30.0 -108.0 0.0 -180.0 20 Hz 100 1k 10k 20k Figure 10.19 To acoustic devices the same principles applies. Fig.10.20 shows the magnitude response of woofer and tweeter in a box without cross-over network. 110.0 CLIO 180.0 1.00 V CLIO dBSPL Deg 0.80 100.0 108.0 0.60 0.40 90.0 36.0 0.20 0.00 80.0 -36.0 -0.20 -0.40 70.0 -108.0 -0.60 -0.80 60.0 -180.0 -1.00 0.00 20 Hz 100 1k 10k 20k 1.6 3.2 4.8 6.4 8.0 9.6 11 13 14 16 ms Figure 10.20 and 10.21 The two measurements were taken from the same microphone position. Should we ask ourselves which is the summed output we could not answer from the magnitude data alone. Unfortunately acoustic phase is not so easy to handle as electric phase. We are going to base our example on the tweeter, whose impulse response and window settings are in Fig.10.21. Procedure for woofer would be exactly the same. 96 Chapter 10 - MLS
We will take this opportunity to introduce the use of the Wrapped Check Box. Figures 10.22 and 10.23 shows the tweeter phase curve, unwrapped and wrapped. 110.0 CLIO 0.0 110.0 CLIO 180.0 dBSPL Deg dBSPL Deg 100.0 -3312.0 100.0 108.0 90.0 -6624.0 90.0 36.0 80.0 -9936.0 80.0 -36.0 70.0 -13248.0 70.0 -108.0 60.0 -16560.0 20 Hz 100 1k 10k 20k 60.0 -180.0 20 Hz 100 1k 10k 20k Figure 10.22 and 10.23 Reader might wonder if these figures are correct at all and if they have same usefulness, at least visually. Well, the curves are absolutely correct; their visual usefulness is zero for the wrapped curve and low for the unwrapped. Difficulties in getting simple visual information from these curves arise because they are the sum two effects. The first one is the device own phase response. The second is the time of sound flight. The latter does affect the curves much more than the first one, completely burying it. The good news is that it is often possible to separate these two effects. However, bad news, this is not an easy task. Trying to explain it, without going in heavy math, is very difficult. The bibliography in this user manual should be considered as integral part of it here. Within CLIO the time of flight can be removed in several different way, with different degree of accuracy. The most accurate is also the most complicated and is how we are going to proceed. Fig. 10.24 introduces us to Minimum Phase, which is the hearth of the whole procedure. 110.0 CLIO 180.0 dBSPL Deg 100.0 108.0 90.0 36.0 80.0 -36.0 70.0 -108.0 60.0 -180.0 20 Hz 100 1k 10k 20k Figure 10.24 We obtained it selecting minimum phase in the MLS Setting and calculating the phase again. Certain well-behaved systems are defined as Minimum Phase. In these, the phase response can be obtained from the magnitude response by calculation. Another kind of phase (we promise is the last one), is Excess Phase. This is the algebraic difference between true phase, as in Fig.10.22, and minimum phase. It is exactly what we need to separate the time of flight from the device own phase response. We wont use excess phase directly here but a post process of it, Excess Group Delay. Fig.10.25 is the excess group delay of our tweeter vs. frequency. Chapter 10 - MLS 97
Page 1 and 2:
ELECTRICAL & ACOUSTICAL TESTS User'
Page 3 and 4:
CONTENTS 1 INTRODUCTION ...........
Page 5 and 6:
8.5.1 MEASURING AN INDUCTOR .......
Page 9:
1 INTRODUCTION 1.1 ABOUT THIS MANUA
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12 Chapter 1 - Introduction
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2.1 THE PB-4281 PC BOARD AND SC-01
Page 16 and 17:
2.2.3 THE MIC-01 (OR MIC-02) FREQUE
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2.4 THE QCBOX MODEL 4 AMPLIFIER & S
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Figure 3.1 2) 2 x Stereo mini jack
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3.3 HARDWARE REGISTRATION WITH WIND
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3.3.2 HARDWARE REGISTRATION UNDER W
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3.3.3 HARDWARE REGISTRATION UNDER W
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Figure 3.21 Let's now verify that t
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3.4 SOFTWARE INSTALLATION This para
Page 32 and 33:
3.6 RUNNING CLIOWIN FOR THE FIRST T
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3.7.1 CALIBRATION VALIDATION Figure
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36 Chapter 3 - Installation
Page 38 and 39:
38 Chapter 4 - Troubleshooting CLIO
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5.3 CLIOWIN DESKTOP The CLIOwin des
Page 42 and 43:
It is possible to generate the foll
Page 44 and 45:
Fig.5.5 Microphone sensitivity dial
Page 46 and 47: 5.5.2 CONTROLLING A TURNTABLE Fig.5
Page 48 and 49: 5.6.2 ANALYSIS MENU The Analysis me
Page 50 and 51: H Enables the Hold function. Equiva
Page 52 and 53: CTRL+P Swithces on and off the micr
Page 54 and 55: 5.7.2 CONNECTING A MICROPHONE For a
Page 56 and 57: 56 Chapter 5 - CLIOwin basics
Page 58 and 59: When you find a CLIOwin data file i
Page 60 and 61: Enters the Notes dialog where it is
Page 62 and 63: 6.3.5 CALIBRATION File > Calibratio
Page 64 and 65: 6.3.7 STARTUP OPTIONS AND GLOBAL SE
Page 66 and 67: 7.3 BUTTONS AND CHECKBOXES Moves (s
Page 68 and 69: 7.6 THE MLS TIME DOMAIN DISPLAY Whe
Page 70 and 71: 8.2.1 TOOLBAR BUTTONS Starts the me
Page 72 and 73: This operating mode is very useful;
Page 74 and 75: Figure 8.7 With the Multi-meter run
Page 76 and 77: 76 Chapter 8 - Multi-Meter
Page 78 and 79: 9.2.1 TOOLBAR BUTTONS Starts an FFT
Page 80 and 81: 9.4 FFT AND RTA OPERATION The FFT a
Page 82 and 83: 9.5 AVERAGING Averaging plays a ver
Page 84 and 85: 9.6 TIME DATA DISPLAY (OSCILLOSCOPE
Page 86 and 87: 10.2.1 TOOLBAR BUTTONS Starts an ML
Page 88 and 89: 10.2.4 MLS POST-PROCESSING TOOLS Lo
Page 90 and 91: 10.4 MEASURING FREQUENCY RESPONSE I
Page 92 and 93: 150.0 CLIO 180.0 150.0 CLIO 180.0 O
Page 94 and 95: MLS Menu, select dBSPL as Y scale u
Page 98 and 99: 110.0 CLIO 7.50 dBSPL ms 100.0 6.00
Page 100 and 101: 10.5 OTHER TIME DOMAIN INFORMATION
Page 102 and 103: utton. Any process you execute can
Page 104 and 105: 104 Chapter 10 - MLS
Page 106 and 107: 11.2.1 TOOLBAR BUTTONS Starts the s
Page 108 and 109: Stepped is also not checked. Typica
Page 110 and 111: 11.3 A BRIEF DESCRIPTION ON SETTING
Page 112 and 113: 11.3.3 GATING Enabling Gating allow
Page 114 and 115: 11.4 DISTORTION AND SETTINGS Sinuso
Page 116 and 117: Finally Fig.11.12 shows the distort
Page 118 and 119: 12.3 WATERFALL BASICS Figure 12.2 W
Page 120 and 121: 12.4 MAKING A CUMULATIVE SPECTRAL D
Page 122 and 123: Let's now change the CSD aspect aga
Page 124 and 125: Figure 12.11 12.5.3 TAKING THE MEAS
Page 126 and 127: Figure 12.17 The final result for o
Page 128 and 129: If you are novice in using CLIO or
Page 130 and 131: -10.0 CLIO dBV -30.0 -50.0 -70.0 -9
Page 132 and 133: 13.4 I SENSE Requires Audiomatica C
Page 134 and 135: Figure 13.12 Lets proceed now with
Page 136 and 137: The figure shows us we are going to
Page 138 and 139: 13.7 THIELE & SMALL PARAMETERS 13.7
Page 140 and 141: L 1kHz L 10kHz Inductance at 10kHz
Page 142 and 143: Now we can save our complete result
Page 144: [19] M.O. Hawksford, “Digital Sig
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