Audio engineers are always on the lookout for innovative ways to enhance mixes. While traditional audio processing techniques like EQ and compression remain essential, there are less conventional methods that can be used to address issues or shortcomings in our productions. In this article, we'll explore three such techniques: Use of Saturation and Harmonic Exciters, Use of Creative Reverb and Delay and parallel processing.

Saturation and Harmonic Exciters

Equalisers can adjust the relative levels of frequencies which are present in the audio you’re mixing but you can’t boost (or cut) what isn’t there. But saturation plugins and harmonic exciters add new frequency content which is musically related to the original audio.

While there are many flavours of harmonic distortion, saturation is the most useful because it is the most subtle, adding anything from barely perceptible warmth all the way to aggressive distortion. It’s a huge subject and the sheer number of saturators available is testament to the variety of tones and tastes available but if you want to experiment the most important advice we can offer is to listen in the context of your full mix. This is always good advice but in the case of applying saturation it’s crucial as you’ll probably find that what sounds distorted in solo sounds much cleaner in context, but fuller and smoother without being significantly louder.

Exciters are related in that they also create new harmonic content but whereas saturation is a broadband process, exciters operate only on the top end through the use of a high pass filter. This allows them to create their characteristic high end sizzle without the added midrange content created by saturators which can tend to dominate.

Use saturation on individual tracks, like vocals, drums, or guitars, to add a sense of warmth and analog-like distortion. It’s particularly effective on bass and drums. Harmonic exciters, on the other hand, are great for enhancing brilliance and sparkle in the high-frequency range of instruments which could use a top end lift when EQ isn’t enough. Particularly effective on pop vocals but watch out for sibilance!

Creative Reverb And Delay

While standard reverbs and delays serve essential roles in providing a sense of space and depth, creative reverb and delay techniques can introduce new options. The most important thing is the correct wet/dry balance but after basic housekeeping like this and delay or decay times are dialled in, what next?

Firstly should you be using reverb, delay or both? They both wetten up the signal, but in different ways. They can push the sound back but don’t have to. And how much it too much?

Reverb predelay can be used to detach the dry signal from the reverb, allowing you to keep the immediacy of a signal while keeping the reverb higher in the mix if that’s what you want. An extension of this idea is dynamic reverb or delay, the technique works just as well on either. This technique involves use of a ducker on the effect return, keyed off the dry signal. Using a vocal as an example it pushes down the level of the reverb or delay when the vocal is present but allows the reverb or delay to swell and bloom into the gaps where is isn’t competing with the vocal, allowing the use of more effect overall but without the downsides associated with lots of reverb or delay.

It’s common to find the sweet spot between too much and too little reverb or delay is rather narrow and both of these techniques help you get the benefit of using more reverb without so much of the negative consequences.

Parallel Processing

Parallel processing is a technique where engineers blend the processed and unprocessed signals, allowing for controlled effects without compromising the dynamics of the original sound. Increasingly this is done using dedicated mix controls in plugins but this was traditionally achieved through the use of send return loops using an aux send to send a blend of signals to the processor and blending the results back in with the unaffected signals using a dedicated mixer channel.

The convenience of using mix controls is appealing but I almost always set up a send-return loop for parallel processing because it is then available to be shared with as many sources as I like. When using a mix control the effect is only available for a single source.

The usefulness of sharing parallel processors across a session isn’t only that more than one channel can be routed to the processor, it’s also that a channel can be routed to more than one parallel processor at the same time, in any combination. This is fundamental to Michael Brauer’s highly developed mixing technique. The specifics of that are beyond the scope of this article but you don’t need to copy his technique precisely to set up two or three contrasting styles of parallel compression, with compressors which have some character, and to shape and colour your mix by using them in varying proportions across it.

Concentrating on unconventional processing at the expense of the unglamorous fundamentals like getting a good balance off the faders and sympathetically automating those levels isn’t a good idea, but using techniques like these to create the homogeneity which underpins great mixes can be very useful. These are only and handful of techniques, what do you do beyond the essential basics to give your mixes a lift?