Thanks for that man! The music is metal and the vocalist has an SM57 which we'll use. I had previously planned to buy myself a decent mic and mic pre and start experimenting with all this, but I lost my job, so I cant buy shit until I find another job. So I have to work with what we have.
Now, for the question that will probably make you all cringe....What exactly is compression? I've never used it on anything and have no clue how to add compression to something. What exactly is it used for and how do I use it?
It's all right man, everybody has been a beginner before, there are no stupid questions.
Compression is one of the most important and least understood tools that an audio engineer will use. In essence, it allows you to shape the dynamics of an audio signal...or in layman's terms, it's a piece of equipment that allows you to control the volume of different parts of a waveform.
Lets use a snare drum as an example. There are two parts to the snare drum waveform, the attack and the transients. The attack is the actual contact of the stick on the head, and the transients will be the vibration of the shell, the snares, the room sound, etc. Obviously, the attack will always be a lot louder than the transients.
You can set up the compressor to catch the attack of the snare drum and bring it down to the level of the transients...thus making a more even and full-bodied snare sound. You're making one part of the snare hit quieter, and the other seemingly louder.
In that example you are not only using the compressor to control the dynamics, but you're also using the compressor as a sort of "dynamic EQ," because you're taking advantage of the compressor's abillity to completely morph a sound. There is a very popular Waves C4 preset for guitars around this forum that is more of an EQ effect than compression.
When you're using a comp on vocals you want to make everything even. Depending on the vocalist and music there might be a lot of dynamics (changes in volume) in a verse or chorus, so when you mix an uncompressed vocal track in with the rest of the music there are going to be words or phrases that will be buried, while simultaneously having certain parts that are too loud. A compressor enables you to keep the volume at a fairly constant level.
Compressors have a few basic different controls that you'll need to know. Threshold, attack, release, ratio, gain-reduction, and make-up gain.
The threshold is calibrated in dBs. Set your threshold for -10dB, and any peak above the -10dB mark will be compressed.
Attack is how fast the compressor will grab a transient. This control is usually calibrated in milliseconds (ms). If you're compressing a snare drum and you want a little bit of the snap (attack) to get through, then slow up the attack setting and the compressor will let the snap get through before yanking down the gain.
Release is how fast the compressor will let go. This is also usually calibrated in ms. Generally, keep the release too fast and you'll hear pumping, keep it too slow and it'll step all over other transients. Pumping is when you can actually hear the compressor reducing gain.....usually it is undesirable but sometimes it can be used creatively.
The ratio control is how much the compressor will compress. This written as 2:1, 3:1, 4:1, etc. A ratio of 4:1 means that for every 4dBs that the signal goes above the threshold, only 1 dB will come out. 8dBs over the threshold and 2dBs will come out. 3dBs go in, .75dBs will come out.
Gain-reduction is a level meter that actually tells you how many dBs the compressor is actually shaving off your levels.
Make-up gain is sort of like an output control. Naturally a compressor is going to be dropping the gain on your signal a lot, so you can crank up the make-up gain to "make up" the loss in volume from the compressor.
Anywho, compression is very important. Every engineer uses it differently, and it takes a long time to get the hang of, so just practice. There is so much more to compression than what I have just explained. There's knee settings, high and low level compression, mulitband compression, parallel compression, sidechain compression, expanders, limiters, buss compression, de-essers etc. etc.
My best advice is to just surf this forum and others like it and just listen to how people use it, and where they use it. Or better yet, get an internship with a decent AE and learn first hand.
Oh yes, and a large portion of learning how to use a compressor, is also learning when
NOT to use it.
