Using Side-Chain Compression and Parallel Processing to Get the Drums in Your Beats Just Right
|By DAVE WALKER (IMPERIAL)|
Drum production in hip hop is about more than selecting the right sounds and putting them in the right places. Having a wide range of mixing techniques at your disposal goes a long way in helping you get that overall drum sound that you’re after.
This article explores two mixing techniques that I often use along with my drum production techniques. These techniques will help give your drums clarity and punch. For example, I used these techniques on my remix of “Tower of Cards” by Mr J Medeiros, which I include below, along with accompanying audio and images to help you understand the processes involved. The images are taken from Logic Pro but the principles apply to any DAW.
Compression is one of the most commonly used processors, yet it is commonly misused. (You can make or break a track with compression!) Essentially, compression reduces the dynamic range of a signal, making the louder things quieter and the quieter things louder. For further reading on compression and parameters go here: http://www.beattips.com/beattips/recording-mixing-and-mastering/
A compressor begins reducing the volume of a signal when the input source goes above the threshold. The input source is typically the signal you want to compress. However, most compressors have side-chain (sometimes called ‘key’) inputs. A side-chain input allows you to use another channel to control the compressor, as opposed to the channel the compressor is inserted on. Side-chain compression is heard on the vast majority of dance records with a compressor acting on the whole mix, and being controlled by a side-chained kick drum. This ducks (reduces the volume of) the signal of the entire mix when the kick drum plays. To hear this in fully effect listen to Daft Punk’s ‘One More Time’
Low frequency muddiness is always an issue in hip hop. You want to get the most out of your kick drum and bass, without them having to compete against each other for space in the mix. Side-chain compression can be really helpful in cleaning up the low end of your mix and providing that space. A common application is to use a compressor with a side-chain input from your kick drum to duck the bass. This enables the kick to poke through the mix and not be masked by the bass.
First off, add a compressor to your bass channel and select the side-chain input from your kick channel. In Logic the side-chain input is selected in the top right corner of the compressor. To ensure the compressor reduces the signal of the bass quickly, use a fast attack (under 10ms) and set the response to peak level not RMS (average level). The release time is important in deciding how quickly you want the bass to return to its original volume after the kick drum has stopped playing. I have used a quick release time of 9.5ms. By juggling the threshold and ratio the bass signal is reduced by 5dB when the kick plays. This is a subtle amount of gain reduction, but enough to ensure the kick is not masked by the bass. Listen to the examples below to hear the drum and bass mix with and without side-chain compression. Notice how the kick pokes through the mix when side-chain compression is used.
Bass without Side-chain compression: BASS_S-C_CompressionOFF.mp3
Bass with Side-chain compression: BASS_S-C_CompressionON.mp3
Parallel processing is another technique used to creatively add punch to your drums. It allows you to have a dry (unaffected) signal and a wet (affected) signal playing at the same time. In hip hop, it’s common to utilize parallel compression (also known as NY Compression) on the drum stem (sub group), or even entire mix during the mastering stage. If applied to the drum stem the result is extra power and RMS level without losing the dynamic variation and transient attack of the drum hits. Some producers will also add shelving EQ in conjunction with compression to bring out the low and high frequency content.
Parallel processing isn’t limited to compression. You can use all sorts of processors and effects creatively to blend in with your unprocessed signal. In this remix I have used parallel processing on the drum stem, to compress, distort and EQ the signal. To set this up in Logic Pro, I sent my individual drum channels to a stereo aux channel (labeled ‘Dry Drums’) to create the drum stem. Via a bus send, I have routed the drum stem to another stereo aux channel (labeled ‘Para Drums’) ready for parallel processing (see image above/below/left/right).
The compressor on the parallel processed channel is reducing the dynamic range of the drums by 15dB. This is heavy compression and is used to increase the average level of the drum track. Distortion is then added through Logic’s inbuilt guitar amp simulator ‘Amp Designer’. This is giving the drums the crunchy character needed for the track. Using EQ, I have scooped out 12dB centered around 1.5kHz as the Amp Designer is adding unwanted resonances in the mid-range. The volume fader of the parallel channel is lowered; it isn’t intended to dominate the drum mix, rather add depth, character and reinforce the unprocessed drum stem.
Listen to the examples below to hear the drum stem with and without parallel processing. Notice how the average level is louder and the distortion adds texture, depth and crunch to the drums. This is all achieved without losing the dynamic range and transient attack of the drum hits.
Unprocessed Drums: DRUMS_Parallel_ProcessingOFF.mp3
Parallel Processed Drums: DRUMS_Parallel_ProcessingON.mp3
Like many production techniques, make sure that you understand what you are doing and why you are doing it before you begin, as this will help you achieve better results.
You can listen to the full track in the player below.