Pumping and Breathing (Compression)

[jnorman]

in a certain sense, you can think of a compressor as an automatic gain control, like in a cheap tape recorder. the more you increase the threshhold setting, the more compression takes effect (soft sounds are amplified and loud sounds are reduced). at very high levels of compression, if no sound is being input, the gain in the compressor circuit is raised, and you will hear lots of room noises, then as soon as you input some signal, the gain goes way down, and all the room rumble/hiss goes away. when you stop playing, the compressor shoots the gain way back up again, as it tries to maintain a consistent signal strength - this is the pumping and breathing sound you get from high compression levels.

 

[nay]

I've read page after page describing pumping and breathing from a compressor... but what does it sound like? Actually sound like? I've compressed the hell out of stuff on soundforge just to hear what pumping and breathing sounds like. I definately hear a difference in the sound but I'm not sure that it could be called pumping or breathing.

 

[The Green Hornet]

Yea, Nay, here's what I say:

I had a compressor hooked into my old rig which consisted of a 488 Tascam; but, try as I may or might I never noticed much improvement to the quality I got from the 488. There was the delay or cut off in sound if the box was pushed enough; discovered I could do without it and it is now entombed in my basement storage area. But, I no longer use the 488/ switched to MD-8 digital.

So easy to rewind - push the button and it's back to start. Sound is not as good as the Roland boxes but maybe one of those is next for me or the Korg which is supposed to be easier to operate. Hate those learning curves.

Have fun,
Green Hornet

 

[Shailat]

Nay,
If it's important to you I'll send you a mp3 example via email, of pumping and breathing.

 

[nay]

Thanks Shailat but jnorman explained it in terms I could understand. Now that I think about it... I think I have heard exactly what jnorman was speaking of (the background noise). Thanks all for the input!

 

[sonusman]

I think a clarification is due here.

While jnorman's description is a good one, he mentions that the compressor is "turning up lower levels". That is not what a compressor does.

A compressor only compresses hotter signals, or turns then down if you will. The idea of it turning up lower passages comes from the "make up gain" that you may apply at the output of the compressor. So in a sense, it sounds like the lower passages are being turned up while the louder ones are being turned down. But really, you are just automatically turning down the hotter signals, and applying some make up gain because the overall signal seems quieter. So the lower signals will sound louder for sure.

Pumping and breathing can be avoided with tachtical uses of the attact and release knobs on your compressor. You should really play around with these. They really make a big difference in how the compressor actually works.

Ed