Philth Tips #11 – mixing week 6 (dynamics – part 2)

Last week we looked at dynamics processors, in particular compressors. This week we will add some new tools, and consider how we can apply dynamics processing to groups of sounds.

 
Dynamics processors

Transient shaping – shape the Attack (the transient) and Release (the tail) of a sound. Particularly effective with drums to make them more pokey or tighter.

Noise gate – used to cut background sounds. The gate will only open when the signal goes over the threshold, so only the loud parts of a track pass through the gate. Very effective on live drums to remove the noisy background in between hits.

Saturation – using Overdrive and similar plugins will limit your sounds and also create harmonic distortion. This effectively makes things sounds thicker and fatter.

Limiting – stops signal going over 0db and clipping the channel. However be careful as running into a Limiter too hot will still cause distortion.

Clipping – some compressors have built-in Distortion. This enables you to clip the signal and squeeze it up to appear louder without leaving spiky transients.

 
Applications of compression

Buss compression
Using a compressor on a buss group will help to hold all the sounds together by reducing their dynamics and shaping their transients as a group rather than individually. For example – compressing layers of vocals to avoid sudden peaks; compressing all of your drums as a group to avoid peaks and also potentially make your drums pump. This is why people refer to buss compression as ‘glue’, sticking groups of sounds together.

To use this technique you simply need to route all your drums/vox/etc directly into a Bus track instead of going straight to the stereo output. Then when you apply plugins to this Bus they affect all of the incoming audio at the same time. Now a compressor will respond to your entire drum mix. You can setup the compressor to emphasise transients, to reduce dynamic range, to cut off any peaks…. all of the normal uses of compression but applied to your whole drum mix, processing it all together.

This also means you can apply Saturation or Limiting (or even both) at the end of your chain, which will cut off any peaks and recover some headroom. Then you can push your drums up so they appear louder in the mix without using up all of your headroom. My absolute favourite tool for this is Camel Phat at the end of the drum chain to give the drums an extra squeeze.

 
Parallel compression
This technique involves mixing a heavily compressed signal back into the original dry signal. Most commonly used on drums (for extra impact and energy) and vocals (solid signal with the impression of dynamic range).
Set up an auxiliary channel and use aux sends to choose which signals are routed to the compressor. You can then apply aggressive compression to your signal (no dynamics on vocals/exaggerated pumping drums) and use the aux fader to mix this signal with your dry signal. I normally set up a final bus to group the dry and parallel signals together for a final bit of control.

When writing DnB I use parallel compression on my drums in a variety of ways, depending on the style of track.
For minimal or techy tracks I will push the compressor on the parallel chain to emphasise transients (hard compression, Attack/Release set to let the drums poke before they are compressed), I will then double the effect by using an Enveloper to cut the tails and push the initial attack. When you mix this back into your original drum mix you end with a very tight and snappy sound, spiky drums.
For liquid I will often go in a completely different direction, and use the parallel compression to bring out the shuffles of my breakbeats by having a very short attack then timing the release to let the shuffles jump out. Using the Soft Clipping feature in the Logic compressor will squeeze the drums more and result in the shuffles appearing to pop out of the drum mix. This can then be mixed with the dry signal to achieve a swinging or pumping effect.

Dynamics - parallel compression

This first screenshot shows how the two drum busses are mixed into a final drum bus. This Drum Master channel makes it very easy to adjust the volume of the drums in relation to the rest of your mixdown.

The Parallel is compressed aggressively, with a fast attack and release to ensure all transients have a POP. The Enveloper is pushing the first 10-20ms of the transients to bring out more poke, which is then clipped with the Overdrive.

The Drum Mix is compressed gently, a little squeeze after letting the first 50-60ms punch. Then the UAD plugins are a Tube Amp for saturation, a Neve EQ which is bringing up the bass of the kick with a low-shelf, and finally, Overdrive to catch peaks and squeeze a bit more.

On the Drum Master there is EQ on the whole drum mix, in this instance to push the mids, and finally Limiting to push up the perceived volume while avoiding any peaks.The result is the brick wall of drums you will see below.

In this second screenshot, you see the effect that each stage of processing has on the audio. The end result is thick fat drums that are controlled by the Limiter.

Dynamics - processing drums.png

 

Philth Tips #10 – mixing week 5 (dynamics – part 1)

I had a break for a few weeks while I was away. Now I am back at work, and back in geek mode. This week and next week I am teaching my students about dynamics processing. That means compression! The following are my notes from the first class. There will be a second part next week when we delve further into the application of these ideas….

Dynamics = loud and quiet

Dynamics processors control the amplitude of your audio, and enable you to shape sounds by manipulating their natural dynamics.
Compression

FACT – compression does not make sounds louder. A compressor attenuates (reduces) the signal. It is only when you use the Make Up Gain afterwards that a sound becomes louder.
Compressors can be used to reduce the dynamic range of an audio signal, which can then be boosted thereby creating an impression of a louder overall signal. This is what is meant when you hear that a compressor ‘makes things louder’.

There are 5 key features you will find on every compressor:
Threshold – this determines when the compressor starts working. When the amplitude of the signal goes over the threshold the compressor starts working.
Ratio – how hard the compressor works.
Attack – how quickly the compressor start working (grips the signal).
Release – how long the compressor takes to go back to zero compression (lets go).
Makeup Gain – this boosts the signal after the compression as taken place.

Other features you may find on your compressor.
Knee – the curve between compression and no compression
Mix – enables you to mix the compressed signal with the dry signal. This effectively enables you to use parallel compression to combine dry and wet signals.
Distortion – many hardware compressors naturally create harmonic distortion (the nice kind!). This feature on the Logic compressor enables you to emulate this natural distortion and effectively saturate the signal.
Saturation = squash = thicker signal.
Drive – similar to the drive on a filter, this will saturate the signal.

Applications of compression

Controlling signal with wide dynamic range
Some signal, such as vocals, will have a very wide dynamic range. This means that some of the quieter words may get lost in the mix, or the loudest parts are too powerful and overpower your mix. In this instance, you will use a compressor to reduce dynamic range and create a more level signal. Be careful though – completely removing dynamic range will suck the life out of the performance.

Look for the loudest part of your signal and set the threshold and ratio so that this section of the signal is controlled (without completely killing it). The attack and release will determine how aggressive the compression sounds. No attack will means the compressor acts immediately but also kills the natural transients of the signal. The following three examples show the ways we can use compression to control vocals.

Dynamics - compression - no attack
In this example, the compressor has been set with no attack at all (0ms). This means that all of the transients are being lost, and as the compressor’s threshold was set pretty high, all the vocals are being squashed so much that there is practically no dynamic range. This vocal will cut through a mix, but there is no sense of the vocal building up and it will sound very unnatural. The louder parts are simply being squashed more.

Dynamics - compression - fast attack.png

In the second example, the attack time has been pushed up to around 80ms. This means that some transient information is getting through (although you can see some strange spikes which appear to have been caused by the compression), retaining some of the original delivery. The threshold was also reduced slightly so the compression was less aggressive, and the result is a more dynamic vocal. However these spikes are definitely a problem.

Dynamics - compression - soft clipping

In this third example, the attack and release were left the same, but the Distortion feature of the Logic compressor has been engaged. This Soft Clipping has meant that the spikes in the previous example are gone, and the quieter moments are squeezed up a bit louder. This has resulted in more headroom, but still an impression of dynamic range. What you can’t hear from the screenshot is the warmth or thickness that harmonic distortion provides to an audio signal.

Shaping individual sounds
A compressor can be used to manipulate and accentuate the natural dynamics of a sound. For example drums… you can use a short attack (30-100ms) to allow the initial hit (transient) of a drum to hit as normal then the compressor grips the signal. You can shape the front of your drum hits to emphasise the first punch. This can result in very punchy tight drums, but also very spiky drums which will need to be controlled afterwards.

You can achieve similar effects by using a transient shaper to control the attack and release of a drum hit. Combining both tools give you maximum control over the shape of your drums.