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Jimbo · 12th May 2006

Ulysses: Thanks for the "better-than-textbook" explanation. All three of those paragraphs were extremely enlightening.

tINY: You were spot-on. I was overdriving the compressor. This compressor isn't like others I have used. It's a limiter with a soft knee. There is no ratio, rather an "Input Sensitivity" and "Gain Reduction" pots. The labelling on the unit is somewhat confusing, and the manual is only one page -- you can find it on the Demeter website if you interested -- and the manual uses a different nomenclature than what's actually labelled on the compressor. It was given to me by a friend, and I've only used it a few times. I've always just fooled around with it until it sounded good.

---
So, I did a test this evening. I ran vocals through the compressor at 5 different settings, using the makeup-gain pot to normalize the output to -6dBu

1. "Bypass" - Bypassing the compressor resulted in no shift in the resulting waveform.
2. 0dB Gain Reduction - When the gain-reduction pot was set to zero, there was no shift in the resulting waveform. However, the amplitude of the waveform was compressed, slightly -- Interesting!
3. -10dB Gain Reduction - With the gain-reduction pot set to -10, there was a noticible shift in the resulting waveform. However, the amplitude did not look any more compressed than at "0dB Gain Reduction".
4. -20dB Gain Reduction - With the gain-reduction pot set to -20, there was the same shift in the resulting waveform as the "-10db" setting. The amplitude did not look any more compressed than at "0dB Gain Reduction".
5. -30dB Gain Reduction - Results were the same overall as with "-20dB".

Of course, as the gain-reduction was increased, there was increased compression of the signal, but the resulting waveform was fascinating.
The fact that even with zero gain reduction, the fact that the signal was going through the compressor circuit, AND there was a waveform shift confirms what Ulysses said about the second-order harmonics causing shift.

This compressor -- when used correctly -- definitely has a soft touch. Now that I understand it, I expect some good things to happen when tracking vocals or sloppy fiddle players.

I perform, compose, and record acoustic music (bluegrass/folk/americana). The recording part has been just a hobby, but I recently took it up a notch when I decided to get dirty with electronics and start building gear. The geeky part of the biz is really interesting for me -- However, I have no training in electronics or mechanical engineering, so this is new territory for me.

I really appreciate everyone's help with this. I'm going to stay tuned to this section of the forum.

Thanks!

- Jim

12th May 2006	#9
Jimbo Lives for gear Joined: Oct 2005 Location: Pennsylvania Posts: 2,518 Thread Starter	Got it! Ulysses: Thanks for the "better-than-textbook" explanation. All three of those paragraphs were extremely enlightening. tINY: You were spot-on. I was overdriving the compressor. This compressor isn't like others I have used. It's a limiter with a soft knee. There is no ratio, rather an "Input Sensitivity" and "Gain Reduction" pots. The labelling on the unit is somewhat confusing, and the manual is only one page -- you can find it on the Demeter website if you interested -- and the manual uses a different nomenclature than what's actually labelled on the compressor. It was given to me by a friend, and I've only used it a few times. I've always just fooled around with it until it sounded good. --- So, I did a test this evening. I ran vocals through the compressor at 5 different settings, using the makeup-gain pot to normalize the output to -6dBu 1. "Bypass" - Bypassing the compressor resulted in no shift in the resulting waveform. 2. 0dB Gain Reduction - When the gain-reduction pot was set to zero, there was no shift in the resulting waveform. However, the amplitude of the waveform was compressed, slightly -- Interesting! 3. -10dB Gain Reduction - With the gain-reduction pot set to -10, there was a noticible shift in the resulting waveform. However, the amplitude did not look any more compressed than at "0dB Gain Reduction". 4. -20dB Gain Reduction - With the gain-reduction pot set to -20, there was the same shift in the resulting waveform as the "-10db" setting. The amplitude did not look any more compressed than at "0dB Gain Reduction". 5. -30dB Gain Reduction - Results were the same overall as with "-20dB". Of course, as the gain-reduction was increased, there was increased compression of the signal, but the resulting waveform was fascinating. The fact that even with zero gain reduction, the fact that the signal was going through the compressor circuit, AND there was a waveform shift confirms what Ulysses said about the second-order harmonics causing shift. This compressor -- when used correctly -- definitely has a soft touch. Now that I understand it, I expect some good things to happen when tracking vocals or sloppy fiddle players. I perform, compose, and record acoustic music (bluegrass/folk/americana). The recording part has been just a hobby, but I recently took it up a notch when I decided to get dirty with electronics and start building gear. The geeky part of the biz is really interesting for me -- However, I have no training in electronics or mechanical engineering, so this is new territory for me. I really appreciate everyone's help with this. I'm going to stay tuned to this section of the forum. Thanks! - Jim