Using Software Compressors w/recording apps.
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Posted on Nov 19, 2003 07:40 pm
GuitarLord
Phatso
Member Since: Mar 31, 2003
I figured i'd start a new topic for this one instead of piggybacking someone else's. (sorry ccseller1.)
db has successfully informed me about threshold and ratio settings for compressor...thanx db, you da man. Now, im curious about what attack and release times are for. What are the proper settings for vocals and guitar? Also, as i dont currently have a hardware compressor that I can use "in-line" with my equipment, is there a way to use a software compressor in real-time while recording? Or is it only something that can be used after the fact?
I had a buddy of mine come over the other day to lay down some vocal tracks, and the problem we were facing was that, in order to stop my recording app from peaking anywhere in the track, the level had to be set to where the low part of the vocals were extremely low to prevent the loud parts form peaking. I know that compression is used to help prevent this, but HOW? Call me clueless, and Im sorry for the stupid questions, but I'm at a loss right now. I guess the best thing to do would be to get a hardware compressor but I just dont have the funds.
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Nov 19, 2003 08:18 pm no such thing as a stupid question, just stupid answers sometimes...ultimately, attack is how fast the compression reacts and release is how fast it lets go...
For example, your stereotypical mother has a high attack and low release, where as the stereotypical father has a slow attack and a quick release. :-D
Nov 19, 2003 08:53 pm Haha, nice way of putting it, dB :)
The only way to prevent clipping when you're recording is to keep the signal being recorded very quiet, or get a hardware compressor to push down those peaks and pull up the overall output before it even gets to the recording program. The problem with not using hardware compression on the way in with something like vocals is that you may end up with a very low signal-to-noise ratio if you have to bring down the signal so low to keep things from clipping that you end up with noise when you turn up the volume in your application. A software compressor works the same way, but it can only work with the audio that's already recorded, so it won't fix clipping that has already occured.
BobMember
Since: Jun 20, 2003
Nov 19, 2003 11:05 pm Hey GL,
I think I know how attack & release works, so I'll give you my rendition on it, for what it's worth. But I must admit, I still have questions of my own.
Attack is how much time until the compressor reduces the gain of the signal to the ratio setting, once it crosses above the threshold. Release is how much time after the input signal drops below the threshold until the gain is increased back to 1:1.
Generally, the faster the input signal changes, the faster (lower time delay values) you should set the attack and release. For instruments that have moderate to long sustain (vocals, guitars, etc) , it's best to use a slow release, so you don't hear a noticable change in the volume level as the signal tails-off. 'Bass pumping' is another compression artifact, that's helped by slower release. The types of peaks most likely to cross the threshold (and cause a reduction in the gain of the compressor) usually contain more bass. When the gain is reduced by the bass pulse, an undesirable drop in the treble part of the signal can be heard. This 'pumping' is less noticable if the treble is allowed to to return gradually (longer release). If you have an instrument with lots of short staccato notes (like a snare), use a faster release, so the gain is set properly (back to 1:1) for the next hit.
So that's my understanding of why you would want to use different values of release. My question to the rest of you experts is : why would you want to use anything other than the fastest attack time? I've heard of people doing this to intentionally allow overshoot. Is that the only reason, or are there other reasons for using a slower attack? It seems to me that if the goal of compression is to raise the overall volume of the signal, without allowing clipping, then wouldn't it almost always be best to use the shortest possible attack?
WaltChief Cook and Bottle WasherMember
Since: May 10, 2002
Nov 19, 2003 11:27 pm Try it out on a guitar and you will hear a vivid change in the tone of the guitar as you adjust the attack time. It's really the same gig as release in a sense. It is amazing what the ear can preceive. A string takes time to develop it's vibration when plucked. In terms of miliseconds it slowly builds to a peak vibration. Unlike a drum strike that peaks fast. Too fast of an attack will actually make a guitar, bass, etc. sound un-natural. Very percussive and harsh; like you chopped off the pluck and delayed recording until the string was at max vibration. Check it out! You'll hear it. Just as you noted with release it will be on the lower range mostly as those are the heaviest strings and the ones that take the most time to develop.
BobMember
Since: Jun 20, 2003
Nov 20, 2003 01:37 am Holy smokes Walt you're right - I just tried that with a guitar and I heard exactly what you described. I guess the piece of the puzzle I was missing was that the timbre of an instrument contains lots of mixed frequencies and the different frequencies can have different rise and fall times. Fascinating. Thanks for explaining that!
flame...bringing sexy backMember
Since: Jul 01, 2002
Nov 20, 2003 05:34 am i never learnt the theory before using compression, i just compressed stuff til it sounded cool!
check in the link directory for the digital fish phones link...theyve got a few BRILLIANT free software compressors that are well worth looking at. also, check out Camelphat Free - excellent for bass and drums.
WaltChief Cook and Bottle WasherMember
Since: May 10, 2002
Nov 23, 2003 01:14 am My pleasure Bob! It's amazing to me the things I have learned by coming here and recording. It's very much like putting sound under a microscope. I have changed a lot of my performing technique as well from recording which has also helped me imensely. I'm really glad I became involved.
