Total Audio Control COMPRESSOR ONE 500 Series, Инструкция по сборке и эксплуатации

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For using an audio analyser a very practical user example is given below (text and pictures courtesy of Udo Terlisten).
To trim the THD we are looking for the overtone structure which is 2 & 4 kHz (1st and 3rd overtone = 2nd and 4th harmonics) at
an injected sine wave test signal of 1kHz.
I used a Wandel & Golterman PS20 as signal generator and a DK MSD600 which was the "Ferrari" amongst all the broadcasters
and engineers in former times. It is a (multi-) level meter, a goniometer, an analyser and way more.
For Windowing I used "Nuttall" which gives the best performance in dynamic range (often used for distortion measurements).
"Hanning" works great too although it is a compromise between dynamic range and frequency selectivity.
"Hamming" might hide too much of the sought after sideband frequencies.
"3rd octave" mode doesn´t work, so FFT is best.
I crosschecked this on my iPad with "Audiotools" installed which is a cut-down version of "SMAART". One should use a good A/D
converter for these measurements. I had an "RME Babyface Pro" handy, works well.
COMPRESSOR ONE settings:
* Switch to ON
* Dry/Wet-knob fully turned CW to WET
*GAIN MAKEUP set to 0dB
* Filters set to off
* THRESHOLD fully set CW to +20dB,we don´t want the compressor start working but pass the pure audio
* RATIO set fully CCW to 1:1 (as a "precaution" only)
* ATTACK and RECOVERY do not matter as we have a static signal here. I just left them somewhere in the 12 o´clock position