Side-Chain Compression Fun I - disappearing bass drum

In this tutorial I'll teach you the most basic use for a Side-Chain Compressor. This is the reason it was invented.
Ever notice how your bass and kick get all muddy together and you don't get exactly the sound you intended for?
the reason for this is very simple: The kick and the bass are on the same frequencies. They both compete over your attention, The result usually being a musical version of a black eye and hospital bills.
But what if we could teach them to just get along?
The bass has a long sustaining sound. Usually the attack isn't an important part of our bass sound design.
The kick on the other hand is defined by its attack but has no need for a long decay.
That's where side compression comes in: You ask the bass politely to lower (compress) it's volume for a bit every time the kick plays and then raise it back up.
Bingo!
You get a sharp kick for 2-3 ms and then let the bass take over the frequency.

Lets get started!

• Open a new project in Session View and create two midi channels with operator in them.
• One channel should have the drums->kick->house kick preset with a "4 on the floor" pattern:

• The other should have the synth->bass->disco preset with a simple bass line:

• Now press play on the kick clip. You should here a simple kick 4 times each bar.
• Now press play on the bass clip. Suddenly the kick disappears every 1st and 4th beat. Told you, didn't I?
• Let's put a compressor on the bass channel, press the on the compressors title bar to expand the amount of options:

• Turn on side chain and get your input from the Kick channel :

• Well , that didn't work. It sounds exactly the same! Lets see why :
• You've probably noticed by now that the threshold bar is showing the kick track and not the bass track meter. Also you've noticed that the little triangle on the bar is higher than the signal ever reaches. Now start lowering the threshold triangle. You'll notice that the kick really comes out below -35 DB , and not sharp enough , also totally ruining our bass sound.
• Lets make the cut faster, we want the kick to lower the bass immediatly and then let the bass kick in quickly. We'll set the attack as low as it goes : 0.01 ms and set a fast release at around 5 ms.
• Now lets set the ratio of the cut much higher. The ratio is the amount of compressing to be done. For instance , if the limit is set to -35 DB and the ratio is 2.0, a -25 DB signal will be reduced to -30 DB (a 2:1 cut on the excesive volume). Since we want to immediatly cut the bass and let it fade in gradually after the kick , lets go for an extremely high ratio 8 ( in the previous example, a -25 DB signal will be cut by 7/8 towards -35DB meaning it will be -33.75 DB)
• ok, so we have a great sounding kick but the bass sounds really ill. That's because we're cancelling it out too much , there's more room now for the bass. Bring the threshold back up to -20DB and check it out.

We have a wicked sounding kick and a groovy bass. Just for fun, press the bypass button on the compressor and listen to the original mix before the compressor was added and tweaked. The bass sounds a bit punchier now (we gave it back it's attack) and the kick totally disappears on the 1st and 4th beats. Try playing around with the different knobs and see if you can get a sound you like better. Always remember that sound design is a matter of taste.


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Cheers
J