CLIOwin 6.5 PCI User's Manual - Audiomatica Srl

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11.4 DISTORTION AND SETTINGS Sinusoidal stimuli allows CLIO to evaluated distortion in its single harmonic contribution. If not Set in Impedance Mode, CLIO always evaluate harmonics from second to fifth and allows display each one separately via its own push buttons. While it is straight to have meaningful distortion figure of electrical devices, measuring Loudspeaker distortion, in normal environments (without anechoic chamber) is not trivial. We will give only some advise here, relaying on examples, as the topic is far beyond the scope of this User <strong>Manual</strong>. To do this we will use CLIO’s FFT Menu in quite an advanced way. Distortion evaluation is adversely affected by several parameters; Two are the most important. Noise 50 dBSPL of ambience noise, a common figure, usually does not affect Amplitude evaluation which is usually carried out at an average level of 90dBSPL. This is particularly true using CLIO Sinusoidal Analysis capability which, by means of DSP filtering, allows exceptional S/N Ratio. Unfortunately evaluating 1% distortion means looking for signals that are 40dB lower than the 90dBSPL mentioned above, in the same magnitude order of environment noise. Gating Effects Device settling time, not perfect delay removal and reflections arriving within the sampling time (Meter On) seriously affect distortion measurements, creating artifacts. It is advisable to perform a noise evaluation using FFT Analysis. Fig.9 shows two curves, the first (red) is obtained with the Max Hold function, the second (black) with Min Hold. 80.0 CLIO dBSPL 60.0 40.0 20.0 0.0 -20.0 20 100 1k Hz 10k 20k Figure 11.8 The first, a sort of worst case, should be taken as the reference lower distortion floor once risen 10dB at least. The second is useful to identify pure tones in the noise spectrum; these are likely to produce both distortion increase as well as cancellation artifacts. In our case this tones are caused by more than 20 different computer fans, spread everywhere in the room. Supposing we carry a distortion analysis at an average 90dBSPL, residues below 1% are difficult to evaluate up to 600Hz, things going much better at higher frequencies. Remember that the frequency axis should be referred to the harmonic we are looking for, not to the fundamental. The obvious solution to overcome noise is increase level. One way is to put more voltage at the Loudspeaker terminals; unfortunately this increase distortion by its own even if it provide important information regarding the device. The second way is to narrow the Microphone to Loudspeaker distance. The next figures, dealing with Gating Effects, refer to a 114 Chapter 11 - Sinusoidal
Microphone 11.5cm (4.5") in front to a good quality tweeter. FFT size is set to 512 points, the equivalent of 10ms Meter On at 51200Hz sampling rate. Fig.11.9 shows the effects of a wrong delay in capturing a 2kHz 10ms tone burst. All harmonics are buried below the effects of this wrong set. 120.0 CLIO 10.0 CLIO dBSPL Pa 100.0 6.0 80.0 2.0 60.0 -2.0 40.0 -6.0 20.0 0.00 2000 4000 6000 8000 10000 12000 14000 16000 Hz 18000 20000 -10.0 0.00 1.00 2.0 3.0 4.0 5.0 6.0 7.0 8.0 ms 9.0 10.0 Figure 11.9 Fig.11.10 shows the effects of the device settling time as the delay is now correctly set to 0.35ms. 40dB down harmonics (1% distortion) should be visible now. As the tweeter perform better than this what we see is the second harmonic cancelling the broad spectrum caused by the device settling time. 120.0 CLIO 10.0 CLIO dBSPL Pa 100.0 6.0 80.0 2.0 60.0 -2.0 40.0 -6.0 20.0 0.00 2000 4000 6000 8000 10000 12000 14000 16000 Hz 18000 20000 -10.0 0.00 1.00 2.0 3.0 4.0 5.0 6.0 7.0 8.0 ms 9.0 10.0 Figure 11.10 Fig.11.11 shows the spectrum when the delay has been set to 1.5ms. The third harmonic, 64dB (0.06%) below the fundamental is clearly visible. 120.0 CLIO 10.0 CLIO dBSPL Pa 100.0 6.0 80.0 2.0 60.0 -2.0 40.0 -6.0 20.0 0.00 2000 4000 6000 8000 10000 12000 14000 16000 Hz 18000 20000 -10.0 0.00 1.00 2.0 3.0 4.0 5.0 6.0 7.0 8.0 ms 9.0 10.0 Figure 11.11 Chapter 11 - Sinusoidal 115
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ELECTRICAL & ACOUSTICAL TESTS User'
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CONTENTS 1 INTRODUCTION ...........
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8.5.1 MEASURING AN INDUCTOR .......
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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
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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
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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
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38 Chapter 4 - Troubleshooting CLIO
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5.3 CLIOWIN DESKTOP The CLIOwin des
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It is possible to generate the foll
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Fig.5.5 Microphone sensitivity dial
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5.5.2 CONTROLLING A TURNTABLE Fig.5
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5.6.2 ANALYSIS MENU The Analysis me
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H Enables the Hold function. Equiva
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CTRL+P Swithces on and off the micr
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5.7.2 CONNECTING A MICROPHONE For a
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56 Chapter 5 - CLIOwin basics
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When you find a CLIOwin data file i
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Enters the Notes dialog where it is
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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 96 and 97: 10.4.4 PHASE & GROUP DELAY We used
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 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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