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I'm currently studying compression and I have it down packed I think minus one issue.

I am able to get the same gain reduction on a signal no matter how high or low my ratio is. If i want a gain reduction of lets say 5dB, I can get that gain reduction from every ratio be it 2:1 or 8:1 just by adjusting the threshold to be higher or lower on the audio signal.

I'm sure you guys would say that what I am achieving by doing that is just affecting more or less of the signal. Granted.

I have a piano piece and the highest peak to the average volume of the piano is a 3db difference. I lower the threshold 3dB from the highest peaks so now my threshold line is just touching the average volume of the piano. I need a 3dB gain reduction but even with the compressor at a ratio of 100:1, it's not even giving me 2dB gain reduction.

What am I missing here?

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    How did you calculate the peak-to-average ratio of the piano track? How fast is the compressor reacting, does it react to peaks or average/"RMS", and if averages, how long a time window does the compressor consider when calculating what's "average" at any given moment? en.wikipedia.org/wiki/Dynamic_range_compression wiki.cockos.com/wiki/index.php/RMS-size
    – piiperi Reinstate Monica
    Commented Apr 7, 2020 at 7:09
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    And from what kind of metering tool or function did you get the actual gain reduction figure. From the compressor itself?
    – piiperi Reinstate Monica
    Commented Apr 7, 2020 at 8:11
  • Given that i'm new to compression, if you could simply those questions, i could answer them and also i feel the answer would be obvious without questions to someone who uses compressors my friend.
    – SR32
    Commented Apr 7, 2020 at 8:25
  • Our byword here is 'be nice'. Just something to consider as a newcomer! Thanks.
    – Tim
    Commented Apr 7, 2020 at 16:07
  • Hey Tim, I actually have another account but I forget the details. I was the one asking about the physics of music. I may have jumped the gun but its plainly obvious those questions were irrelevant to someone with little knowledge on compression and it felt like a troll move. If hes being sincere and just tone deaf, I sincerely apologise to you piiperi. Nvm, my phone is signed in to my old account.
    – Seery
    Commented Apr 9, 2020 at 0:31

1 Answer 1

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From what you describe, it sounds as if you're trying to use the compressor as a limiter. That is different than using it as a compressor. Compressing the signal does two things. It reduces the loudest parts of the signal and at the same time boosts the level of the quietest parts of the signal. What you hear, can sound as loud, maybe even louder than the original signal because the quieter parts have been boosted in level, and the music takes on a dense character. To use as a limiter, You'll need to set the threshold lower and adjust the compression ratio to achieve your objective. This tip may help you understand what is actually going on with the signal when it is being compressed and when it's being limited. If you can get your hands on an oscilloscope, play a musical track into your compressor and watch the output of your compressor on the scope, and listen to the effect it has on the music thru your monitors at the same time. Try several different settings on the compressor and watch and listen at the same time. I spent many hours doing just that in order to actually see and hear what I was doing with the compressor. The important thing to understand is the different effects a compressor can have on a signal and what those effects can sound like when you use them.

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  • I think you nailed it with the "I'm using a compressor as a limiter". So if thats the case, then this whole "set the threshold below the peaks you want to compress, isn't exactly accurate? To even out an audio signal dynamics, how should i set the threshold if it is not just below the peaks? Thanks very much!
    – SR32
    Commented Apr 9, 2020 at 2:39
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    @SR32- I understand your frustration about trying to gain an understanding about compressors and how they work. Fact is they don't all work the same. My experience taught me that the user's manual only teaches the basics and to know how my equipment is going to handle what I'm asking it to do, I need to have the experience of playing with it and learning how its going to perform. You may find more answers here at this site by stating specifics like what kind of compressor and are you working in the analog or digital realm. The more information we have to work with, the more we can help you.
    – skinny peacock
    Commented Apr 9, 2020 at 15:49

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