I do understand how compressor works, I am a qualified sound engineer for ten years now.
I do not understand how compressor in Renoise works, because it does not do what it is expected to do. The bus compressor seems to do its job quite right, however the basic compressor does not seem to take anything into account.
try splitting the piano signal so you can use different compressor setting for the low/high of the piano., or only compress the highs, normaly piano’s don’t need much compression if at all, unless its dance music ;]
-edit
just saw you have experience, so never mind above ;]
Man, I know what I need a compressor for in case of this piano. Instrument compression is not what I was asking about, the question was about an operation algorithm of a specific device in a DAW, which happens to be a compressor.
My apologies then. When you mentioned that you had both attack and release set to 0.001ms, this just threw me off a little bit, because the compressor will indeed be quite useless in that configuration.
Perhaps this is just a quirk of Renoise’s native compressor design (quite likely). I can’t recall if I’ve seen many other compressors that allow similar settings for attack/release. Most plugins I’ve seen do not allow release to be set so low, for example.
Nevertheless, if you use some ‘sensible’ attack and release values, then the compressor should still perform its job quite well under normal circumstances. I can say that I’ve personally never had any huge problems with it.
Just as a comparison, if I A/B Renoise’s compressor against Kjaerhus Classic Compressor using identical settings in each, I get very similar results overall, give or take a few inevitable minor differences in how each algorithm behaves.
Generally speaking, when I’m trying to dial in Renoise’s compressor, I first tend to set the ratio to max (LIMIT). For me, this just makes it easier to set the threshold roughly where I want it to kick in. After that it’s just fine-tuning everything to achieve the overall desired character.
Your mileage may vary, obviously.
I presume you did the testing only with the compressor and no other (send)devices in the chain? (Just to exclude side-effects from other devices)
Sorry, I thought you were asking bout, “how to use,” but I will leave my OP intact…
Cheers
There was a gainer before the compressor, which I took into account, and also a send afterwards for a reverb, which was muted anyway. Nothing else.
That was purely for the sake of purity. I had a signal just touching on the +2dB mark, so decided to use some compression to soften the peaks without limiting. My math was very simple:
set the threshold to -4dB, which gives us a range of 6dB to the peak of the signal, then apply a ratio of 2:1, so that we should get around the ideal peak of -1dB with a very short attack, which then would be relaxed slowly until it gets to 0dB. The release is not really relevant in this case, as long as it is not too long.
However the basic compressor did not let me arrive at these results, it did not seem to do any compression at all. At the same time the bus compressor works exactly according to the math, taking its minimal attack time of 10ms into account.
am thinking now that it was poor choice of forum section to post this question in, but anyway.
These are the settings that I am using do what I described just above. As we can see, both compressors have pretty much identical settings. The only difference is that the bus compressor works exactly according to the plan, while basic compressor does not compress at all, according to the peak readings from the master.
3442 
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EDIT: Actually, looked into the settings and peaks again, the bus compressor perform darn close to theoretically predicted results.
What does the audio peak at, without the compressor? Should the threshold not start there? I never see movement on the meters, on any comp, unless the audio is it least hitting the threshold… or am I totally wrong?
Now that I am looking at Renoise… I believe the center bar is, “gain reduction.”
These compressors are kicking in with their threshold right about there…
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Renoise project file…
It peaks at about +2dB for the left channel and about +0.3dB on the left without any compression. If I pass it through the basic compressor, nothing changes. If I pass it through the bus compressor, it hits around -1dB on the left channel, as per my estimations. It happens on a six column track, btw, I have a wild guess that it has something to do with it.
Well… Compressors are very funny. For example, I have a favorite compressor I love to use for my drums… However, sometimes this compressor does not compress so well, and I use a different compressor for my drums! 
Actually, compressor are like microphones! You can not have, “just one microphone.” It is so true. And also… I like the Renoise compressors, being similar in sound to the Kjaerhus… That is a very good comparison.
But you know… If there is, “a bug,” with the compressor, I would not know. The only thing I really compress is drums… and for that I use a pspaudioware…
But I do think, if I ever get to make, “very bad major label music,” then I am going to squash everything to bits… Squash, pummel, destroy!
I have tried to reproduce it in a different module but it didn’t work for some reason, both compressors were working about the same way without following my predictions. I had the signal peaking at 0dB on master using a gainer (since there is a 6dB headroom on tracks) and tried to bring it to -2dB using either of the compressors with a -4dB threshold, 2:1 ratio and a very short attack.
Instead this time they both put the peak to about - .3dB, so now I am just posting a pattern from the module I was working on where the issue consistently manifests itself. I had to convert the samples to ogg format to save some space, it changed the peaks somewhat but the issue is still obvious.
Watch the peak readings on the master track while enabling and disabling the compressor.
Here is where your track is peaking…
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The above tool is freeware, very useful btw, and @ sonalkis.com ( spelling error maybe )
Using the tool above, I was able to decipher that you probably need a look ahead limiter. I suggest the freeware version of Event Horizon… ( if it still exists. ) in the Reaplugs pack, at Reaper.fm
Event Horizon is taming this very nicely
Cheers
I’m using the payware, Event Horizon… 
Good stuff. I’ve had it for years, and you just surprised me again with, “how good it is, and how worth the money it is.” I don’t recall the freeware one with VU meters, but I could be wrong… Download the demo, or whatever, and you can hear what it does to your track…
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Why, you have everything pushing zero? I guess you have a reason.
Cheers
Thanks, captain Obvious!
3443 
never mind, have a pleasant day dude…
btw, the sonalksis thing is freeware… it shows rms, its really precise. i’m using it all the time… cause a lot of times my volume goes below where renoise shows me. cause i mix very quiet… there is no need to, “hate on the freeware.”
What makes you think I hate freeware?
Why not push zero? As long as it’s not clipping or altered too much by the compressor why not? Cutting peaks no one can hear is fine by me, I don’t see the problem. The false dichotomy loudness war guys create is ridiculous. It doesn’t have to be squashed or no compressor at all.
What? Who’s hating freeware here? I don’t see what you’re getting at.
