Compressing drums for mixing is an essential tool that when done correctly can really add to not only the sound of the drum kit but it’s impact on the entire mix. The first thing is to understand is compression and how compression affects drums. Downward compression is the most commonly used compression technique. Compression can be used to reduce the dynamic rage of any audio track, to smooth out the peaks or bring the loud parts down. Some compression techniques need to be transparent like some used in Mastering. Although, in pop music it is used to affect the sound of recorded material. Most compressors have features that can be adjusted such as threshold, ratio, attack and release times, make up gain are common ones. There are other compressors that have more features such as soft knee, rms or peak detection, look ahead, stereo linking, etc… For this discussion we will be concerned with just threshold, ratio, attack and release, and make up gain. Before we can delve into compression techniques we need to make sure we have a grasp on how a compressor works.

Threshold- is the threshold/level at which compression kicks in. This lets you pick the db level for compression to start.

Ratio-the ratio of input to output. Ratio is usually displayed for example 4:1 or 4 to 1 would be for every 4db of input over the threshold setting the output only produces 1db of gain.

Attack time- Usually displayed in milliseconds. How fast the compressor reacts to input above the threshold.

Release time-Usually displayed in milliseconds, How fast the compressor returns to unity gain after the level goes below the threshold.

Make up gain-increases the level after compression. After the compression effects the material the overall level can be brought up.

With these concepts in mind there are many ways to approach compressing drums. One technique is to insert a compressor on the drum buss and compress the over all drum mix. If I employ this technique I usually am looking reduce some of the higher peaks of the drum kit. Most of the time I will only run the kick, snare, and toms into this type of configuration because I don’t want this to affect the attack or sustain of the cymbals. The ratio, attack and release time will vary some depending on how fast and percussive the material is. Here is a guide. To start you can set the ratio at around 4 to 1 with a fairly fast attack around 8 to 15ms and a fairly fast release time of 30 to 100ms. Be careful not to use too fast of an attack time (unless thats the sound you want) or you will loose transient information. Change the Threshold up and down until you get the sound of compression you are looking for.

Another technique Parallel compression also know as New York compression is very effective. The basic technique involves running an aux buss with heavy compression routed to the mix buss in parallel to the drum tracks unaffected sent to the mix buss or cloning the drum tracks and having one set of tracks running into the mix buss without effects and the other set of drum tracks with a compressor on a separate buss, both are then sent to the mix buss. This technique will give you the ability to mix the compressed drums in with the uncompressed drums, You can use high compression ratios and a low threshold to mix with the unaffected drums bringing up the lower level subtleties in the drum track without loosing the transients inherent when using fast attack times. Her are some other options you can try

Add low level compression on the unaffected mix to add more continuity. Another technique is to EQ the heavily compressed aux buss which will produce some interesting effects. Try the EQ before the compressor and then after the EQ in the effects chain.