Why can you reach a much higher volume for a vocalist (without feedback) if compression is applied? This has been my experience so far, and I'd like to understand why this is.

When you add an input to a mixer, you're suppose to use the trim knob to turn that input up as far as you can without that input ever red-lining on the meter during the performance.

I was having difficulty maintaining that level for our vocalist. Instead of using the meter to adjust his level, I was having to instead base it on how loud I could turn him up without having feedback, and on the meter, his volume was so low that he was only getting 2 green bars.

I was having difficulty getting his voice loud enough compared to the rest of the band without feedback.

Then, I applied compression to his voice, and the compression feature had it's own gain knob that I could turn up. I was able to get his vocals loud enough by turning up this compression-gain (without feedback).

Later, when I imported the tracks of the practice into Audacity, and played them all raw, I couldn't even hear the vocalist at all until I turn his track way up. Fortunately, in Audacity I didn't have to worry about feedback while turning him up!

Maybe my mistake was that, after applying compression, I should have turn his trim knob up instead of that compression-gain knob found in the compression settings. Perhaps I would have been able to accomplish that without feedback after having applied compression, and this would have resulted in a normal level track recording (instead of a low amplitude recording).

I'm recording "pre" (raw) instead of "post". "Pre" recording is effected by the trim knob, but that compression-gain knob has no effect on raw (but probably would effect the recording had I chosen "post"), so the recording didn't benefit from that solution that seemed to work during the practice.

Next practice, I'd like to achieve a normal level recording on vocals (without feedback). Applying compression seemed necessary to avoid the feedback, yet I'm not sure that raising the volume using that compression-gain knob was the right way to do it. Please advise.

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  • 1
    So your main issue was feedback? I'm curious, what are those high transients on the vocal? If you're getting high peaks like that, you should figure out why, and if it's unavoidable, maybe a limiter would be best on the input while recording. With the threshold set to the correct vocal peaking, so you only (softly) clip these high transients. I don't get how you got those with compression, either. Also, to overcome feedback, just turn down the monitoring output, EQ-cut the troublesome frequency range or try phase inversion, move the vocalist, etc, but maintain a high, clear recording level.
    – n00dles
    Sep 24, 2022 at 17:20

1 Answer 1


Using a compressor in this way gives you the ability to increase the average (or RMS) level of the vocal without significantly increasing the peak level. You are utilizing the output gain knob to "make up" for the loss of level caused by the action of the compressor. This is normal.

  • Since my meter was low at that time I applied compression, should I have increased volume using the trim knob instead of compression-gain (for the recording's sake)? Or, do you think the trim knob would have still caused feedback like it did before applying compression? Unfortunately, after the compression-gain knob solved the live problem, I didn't think (at the time) to even try the trim knob again. Next time, I will try it. Sep 19, 2022 at 16:39
  • 1
    One of your most important jobs is managing the signal levels as they flow through the system. Generally, the final heard volume of a channel is determined by the channel fader. You generally want levels to be "up without clipping" prior to that point. Sep 19, 2022 at 16:43

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