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Help me understand compression.
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Chemogen
IsraTrance Full Member
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713
Posted : Aug 6, 2007 15:25
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Hello there, from South Africa...Recent migration from http://www.bomelakiesie.co.za
I'm working on a demo for my Psytrance project and I think compression is the one fundamental concept I'm having trouble understanding. I've had a LOT of help from friends at Bom, but I still don't think I understand it's mechanics 100%.
I got the hang of EQ practice after reading the incredibly written Thinking Inside The Box tutorial (if anyone knows of a tutorial for compression written in the same tone, I'd be very grateful.)
Now it's onto compression. I've read up scores of different explanations and guidelines, so let me make sure I've got this right...(quoting some guidelines I've found on the net)
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Once you have the ratio set, adjust the threshold control so that about 8dB of gain reduction is showing on the meter at the peak points in the signal |
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Ok, so does this mean that if my kick is peaking at -6db, I want to set the threshold so that it peaks at -14db (8db of gain reduction?)
So is that where the compressor's makeup gain comes into play...Because -14db is too soft a peak for the kick, I need to adjust the makeup gain so that even with the compression on, it peaks at -6db again?
Also, with mastering. If I have a limiter on my mix, so that the loudest elements don't go over 0db, do I use the gain on the limiter to bring all the soft parts up without increasing the loud parts? ie, let's say the loudest parts of my mix are peaking at 0db, while the softer parts are only at around -7db or so, will I use the limiter's gain to increase the soft parts to about -3db or so while the loud parts stay at 0db? (Not exact values, just examples to try better understand the concept.)
Is my understanding of these concepts right?
The thing with me is that I have no formal training in sound engineering, so I often can't tell the difference to a compressed individual sound unless it's REALLY compressed. Although in the context of the mix, I can hear the compressed sound coming through more clearly. Is playing around with the compressor the only real way to better understand it's effects?
For those interested enough, here's a self-mastered mix with compression on the kick, snare, bass and lead that follow some guidelines for the respective instrument, as well as a multiband compressor and limiter.
http://download.yousendit.com/4F2FF32331BCCD74
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makus
Overdream
Started Topics :
82
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3087
Posted : Aug 6, 2007 15:33
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Chemogen
IsraTrance Full Member
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Posted : Aug 6, 2007 15:36
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*blush* |
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makus
Overdream
Started Topics :
82
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3087
Posted : Aug 6, 2007 15:44
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So is that where the compressor's makeup gain comes into play...Because -14db is too soft a peak for the kick, I need to adjust the makeup gain so that even with the compression on, it peaks at -6db again?
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in fact, yes. doing that you'll have the same volume as dry kick, however it would be compressed kick with rised volume
www.overdreamstudio.com |
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Chemogen
IsraTrance Full Member
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Posted : Aug 6, 2007 15:51
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Cool, so is that basically the role the makeup gain plays? |
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astrotec
Started Topics :
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193
Posted : Aug 6, 2007 16:40
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Chemogen
IsraTrance Full Member
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Posted : Aug 6, 2007 18:18
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Thanks a lot guys...Tell me, is there some sort of forumla for working out where your threshold and ratio should lie - in relation to the raw signal's peak (like are there guideline settings I can use for a sound that peaks at -6db, for instance) - for optimum effects, or is it all really very subjective?
I found this online, which seems to be a different explanation of threshold/ratio mechanics than in the link Astrotec posted.
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Part of what compression does is it reduces the amount of volume variance. If a recording has volumes on it ranging from 1 to 10 before compression, it can change them to say only 3-8 after compression (or everything at 5 if you really want that). It first compresses down the volumes above the threshold and does so at the ratio you select. If the threshold is at -20 and your raw recording goes to -8 thus 12 db past the threshold, it will compress those 12 db at your ratio, say 4:1. So 12 divided by 4 is 3, thus what was 12 db past the threshold is now only 3 db past it, or -17. So that compressor just took a -8 signal and made it -17. Now after the compressor is applied the volumes will be lower and hence there is a gain control. The gain raises the volume of everything, both compressed and not compressed. In the example above, a 3 db gain would raise your peaks from -17 to -14.
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It still doesn't really explain how one would go about finding the best threshold/ratio for the sound. A kick peaking at -6db means that the the threshold needs to be at at least -5.9db for compression to take place, right?
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astrotec
Started Topics :
7
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193
Posted : Aug 6, 2007 21:45
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I don't use no formula for compression,
just whatever sounds right for that sound.
and threshold works correspondingly with ratio.
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Chemogen
IsraTrance Full Member
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Posted : Aug 6, 2007 23:20
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Elad
Tsabeat/Sattel Battle
Started Topics :
158
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5306
Posted : Aug 7, 2007 15:15
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for mastering there are 3 basic compression method
*"peak reduction "- small tresh up to -2 or -2.5 and ratio of 1.6:1 or 2:1
*"glue the elements" - very deep tresh like -20 or -25 and ratio of 1.2:1 + -
*"paralel compression" - where you send your signal to 2 channels , one compressed and one not , then mox the signal together. i never was able to do it without harsh phase problems yet..
www.sattelbattle.com
http://yoavweinberg.weebly.com/ |
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makus
Overdream
Started Topics :
82
Posts :
3087
Posted : Aug 7, 2007 15:41
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On 2007-08-06 21:45, astrotec wrote:
I don't use no formula for compression,
just whatever sounds right for that sound.
and threshold works correspondingly with ratio.
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yeap thats absolutely correct way. btw, not only about compression
www.overdreamstudio.com |
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Nomad Moon
IsraTrance Full Member
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134
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1516
Posted : Aug 9, 2007 15:06
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hey there , nice topic, i would suggest u go to the "mother of all basslines"
http://forum.isratrance.com/viewtopic.php/topic/56391/forum/2
and in page 44 there's the best explantion ,made by fuzzykitten ,on how to make things i've ever read , having no engeneering background myself gave me a better knowledge of how things work.
Take care , hope it helped |
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fuzzikitten
Annunaki
Started Topics :
40
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603
Posted : Aug 9, 2007 19:13
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that's 'fuzzi'  |
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shamantrixx
Started Topics :
7
Posts :
549
Posted : Aug 9, 2007 20:44
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On 2007-08-06 18:18, Chemogen wrote:
is there some sort of forumla for working out where your threshold and ratio should lie - in relation to the raw signal's peak (like are there guideline settings I can use for a sound that peaks at -6db, for instance) - for optimum effects, or is it all really very subjective? |
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Formulas like that don't exist (I guess) because each track is different and each producer has different idea about what he wants to get out of it.
I would suggest you not to compress whole mix for a start. Rather try to compress individual tracks because in the mix it is much harder to hear the effect of compression on low volume elements and on overall dynamic. Main formula for compression is training your ear to be able to hear compression without looking into the gain reduction level. That takes some time but once you start paying attention to it you will soon be able compress more complex stuff like entire mixdown.
IMO mix compression should be very mild. It's far better to automate volumes in the mix to get the desired overall volume and compress individual elements (or groups) rather than the mix. You get same result on the end and (unlike master compression) you have a control over what is being compressed and how much. Master comp will compress EVERYTHING louder than X dB in the same ratio.
Another thing that helped me to master compression is parallel compression. You make a copy of audio track (or use send) and use extreme compression settings. That way you'll get to know compressor you're using much faster compared with trying to get subtle results with it. Once you've set compression lower the volume of audio track and slowly raise the volume of compressed track. Beside faster learning this can result in ways that classic compression can't get due to treshold logic. Just be careful with compressors that cause delay because that could result in some phase canceling. In the same time even phase canceling can result in interesting ways...
PSP Mix pack and Kjaerhus GUP compressors have dry:wet controls and you can use them for parallel processing without doubling audio channels or using send!
Have a nice tweaking
"It occurred to me by intuition, and music was the driving force behind that intuition. My discovery was the result of musical perception"
Albert Einstein, speaking about his theory of relativity |
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Nomad Moon
IsraTrance Full Member
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Posted : Aug 9, 2007 23:07
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On 2007-08-09 19:13, fuzzikitten wrote:
that's 'fuzzi'
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 sorry  |
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