I want to talk about a commonly overused piece of gear- the compressor. The basic concept of a compressor is to turn the volume down when the signal gets too loud. A lot of inexperienced engineers think they can put a compressor on almost every channel and then sit back like they’re on auto-pilot. It’s not quite that simple, and using these too often goes against my entire approach of keeping it simple. Just because you read in a magazine that the bass was compressed, doesn’t mean you automatically need to compress yours. Too many compressors, and all of the sudden your mix has no life, no air, and no dynamics. To tell if your compressor is working well or not, there is 1 sure-fire way to find out.

Can you hear it? A well used compressor will not sound like it’s altering the audio or the volume at all. It will be turning down those loud moments, but it will sound natural if the unit is set up correctly. So, how do we set it up?

Let’s first talk about inputs you may want to compress. You want to add a compressor to anything that easily and quickly gets loud or soft before you have a chance to compensate by moving the fader. A good example is a lead singer, who may really get into it at the sweeping chorus of that last song of the morning. Let’s try adding a compressor here.

First of all, don’t put the compressor on a subgroup, and just bus whatever you think needs compressed to that group. Some guys do this, and the problem is, when one of those inputs gets too loud, it turns the whole group down, including everything else besides the loud source.

Instead, connect the compressor at your insert- likely right above the XLR connector for that channel. You’ll need a special Y cable, but you can Google that if this is a surprise to you. Now, let’s look at the compressor. You probably have the following:

• Threshold- when does the compressor start compressing.
• Ratio- how much does it compress. 4:1 means that for every 4dB over the threshold the audio is, only 1 dB is released.
• Attack/ Release- how fast does the compressor react/ release the audio? Honestly, just use the ‘auto’ button.

Some notes. Set the threshold so that the compressor just starts to engage when the singer is at a normal volume. If you see a ‘soft knee’ button, I’d use it. That means it will start to do a little bit of compression as the volume reaches that threshold, giving it a smoother sound.

Ratio really depends on how loud exactly your singer is. Does he really get into it? Try a 6:1. Is he just kind of loud, but the bigger problem is really just volume consistency? Try 2.5:1. I’d suggest starting with 4:1 and adjusting from there.

The only time I don’t like using the auto feature for attack and release is if I’m compressing drums. Obviously, drums get really loud extremely fast, then disappear, until the next beat. For drums, I’ll make the attack as quick as possible, then give it 1 notch to the right. A compressor can’t lower the volume prior to seeing the audio (except on digital boards), and if you try to set the attack to the quickest possible time, you may hear a click as it tries to grab that sound.

Please note, again, these pieces of gear are not about going on auto pilot. You will still need to adjust your faders, just hopefully not as much or as often. If you do hook up a compressor, be sure you know why you want it, where you want it, and that you have a clear understanding of what you are trying to accomplish.