Hello once again! I am Benson Lim from Melbourne and for the forth week of “Introduction To Music Production”, I’ll demonstrate an effective use of a compressor in a musical context.
Why do we need a compressor? Applying compression to a track lowers the volume of the loud sounds and raises the low volumes. How much compression you need depends on the type of music you’re mixing. For example, you might not want use too much compression on a classical music, on the other hand you might want to add more compression on a metal music. Most importantly, do not over compress your sound or it’ll sound “squashed” or lifeless.
So let’s dive into the demonstration. Say you’ve recorded a guitar track. You’ll need to open up the smart controls by going to View –> Show Smart Controls.
On the bottom part of the Garage Band, press the “i” button.
Then scroll all the way down to the plugin section. Garage Band allows you to have up to 6 plugins. Some presets may have a compressor. If yes, just click on the compressor button.
If not, click on an empty slot, and go to Dynamics –> Compressor
You should then see the compressor control screen.
You can either choose a preset provided by Garage Band or you can manually control the compression. First, is the Compressor Threshold. This controls the point at which the compression will kick in. On the screen above, anything above -20dB will be compressed.
The ratio determines how much volume to reduce. The higher the ratio that you specify, the more volume will be reduced. If you lower down the ratio, the compressor will reduce the volume less. For example, in the screen above, it is set to 1.5:1. What this means is for every 1db that your audio goes over your threshold setting, it’s volume will be reduced by 1.5db.
Then, there is the attack. The attack controls the speed of when the compression kicks in. Kick drums, snare drums and certain vocals (rap and hip hop) have very fast attack setting, whereas genres like jazz will have a slower attack speed.
Finally, the gain boost the output level to make up for the lost volume.
So here’s a sample of a recording without any compression.
Now, I’ve added a compression with -12dB Threshold, 3.7:1 ratio, 3 ms attack and 7 dB gain. Click here to listen.
Thanks again for spending time to read this simple demonstration and I hope that you enjoy reading it as much as I enjoy writing it.