Thursday, October 2, 2008

Mmm, tight bottoms

So, you're walking along and there it is, a tight bottom! No, not of the female variety, but audio of course!

Well, we got some more subs on the floor and some folks came in, Christian and Brandon, and they showed me a thing or two about how to get a tight bottom.

It all has to do with compression and when it's applied.

Compressors are used to squash signals under a variety of conditions. These conditions are determined by knobs labeled Threshold, Attack, Release, Ratio, Output Level to name a few. You can use them to tame the occassional hot signal, like when the keyboard changes patches to the unforgiveable "organ" (I don't know why keyboard manufacturers can't get their patch levels the same from one to the next, but I digress).

Threshold is at what level of the signal the compressor looks for work to do.

Attack is how soon after there's work to do, do you really want me to do it, me, the compressor. A setting of 0 (zero) or fully counterclockwise means "right now".

Release is how soon after I've done the compression do you want me to let go.

Ratio is how much squash of the signal do you want, a little bit (1.3:1) or a lot (4:1).

Output Level, sometimes known as make-up gain, is the boost in the signal which isn't compressed to pass thru. I use this on vocals and pastors so that when the compressor does kick in, it's not as obvious that it is. It's one way to maintain an even level.

Anyway, back to our tight bottoms.

What we want is the original signal to pass through and then squashed so all we hear is what we want, umph. This means the attack is a few milliseconds later. This of course needs playing with depending on the room and environment. You can start with say 30ms. Likewise the release will vary depending on how fast the kick drum is playing. You don't want it so high that the next beat of the kick is still squashed since you want to hear it again. 4/4 time, if you know music, might be about 1 beat per sec, and there's 1000ms per sec so 500ms might be a max setting for a release. If the settings aren't quite right, you'll hear the compressor "pumping". We don't want to level the result, so leave the output level at 0. The threshold gets adjusted based on signal level.

That's my simplistic understanding of what I learned last night. Yes, been running sound for a while, and still learning. So, you too! Don't ever stop learning nor thinking you know it all. That's when God will burst that bubble. We all can learn from someone. I just hope that what I wrote in this blog is accurate or close enough to get your bottoms tight.

Serving Him in sound reinforcement,

Ken