Episode 21 – Compression – Calgary sound rentals – Behind the Scene Podcast

Episode-21 Compression

Here an excerpt from today’s podcast.
This weeks tip is on compression.

A compressor is a tool used to control the dynamics of a sound.

Dynamics, in case you are not sure, are differences of volume over time.

A snare drum when hit with a drum stick is a sound that has an extreme dynamic range. The initial thwack of the stick, will produce a very large change in atmospheric pressure in a room, and the resulting ring out of the drum will be lower in pressure.

The thwack has more volume, and the ring out (or sustain of the drum) will be lower in volume.

A compressor can be used to diminish the volume of the thwack by a specific ratio. One reason to use a compressor is to enable engineers to bring the volume of that instrument up in a mix without clipping their hardware, or in the digital realm their software.

Mixing engineers try to make their mixes sound louder than other peoples tracks so they will often squeeze all of the dynamics out of a performance in an attempt to raise the volume just under clipping. In the biz this is known as volume wars.

This is a big problem in particular genres like rock and hip hop. The problem with over compressing is that it will bleed the life, or feel, out of your track because they will lack dynamics.

Let’s take a look back at that snare. If we set a threshold on our compressor to only effect the thwack of the drum then we are diminishing the thwack at a certain ratio. The problem is that a majority of the quality of the drum is in the initial thwack. If we were to take the attack of a different instrument and place it at the beginning of the drums ring out, you would not be able to tell it was a snare at all. So compressing the thwack changes the quality of the drum itself.

For longer tracks like trumpet melodies or guitar rhythms, you could be compressing out the swells and falls of dynamics which greatly effect the mood of a song.

Some people use compression to change the sound rather than to increase a tracks amplitude. Any time you use a compressor it is going to be changing the quality of the instrument. It can have a positive or negative effect depending on how high your ratio is set etc.

I guess what I am saying is be careful not to over compress your tracks or you will leave them feeling dull and lifeless. There is a fine balance between having a vibrant sounding track and one that is loud, but lifeless.

Thank you for listening.
We’ll be back next week.