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How to Mix Front to Back

Sep 24, 2024

Forget left and right for the moment – let’s talk about creating a sense of depth while mixing and how this helps to bring elements forward or backwards in space.

How to Mix Front to Back - Create Stronger Depth in Your Music

When we talk about stereo, we usually think about width – the left/right dimension of our music’s stereo field and the position or size of each element in the panorama between our speakers. But think a little deeper, and perhaps this approach can start to seem a little one-dimensional – literally.

In the quest for creating a spacious mix, why don’t we spend as much time thinking about depth as we do thinking about width?

What Happened to Depth?

It’s very easy to think about width. After all, our two-speaker setups have definite boundaries, and our mixing setups are designed with a control that balances a channel in a position between both sides. But depth is elusive, abstract and infinite. It’s an effect that comes from an obvious property of a sound, but in mixing it relies on many properties being tuned to work together. The reason depth isn’t mentioned on your mixing console? It’s too complex to be a single dial.

Where Does a Sense of Depth Come From in Mixing?

Stereo works on psychoacoustic principles: if a sound is louder in one ear than another, it will be more likely perceived to be coming from that direction. Let’s consider front-to-back position in a similar way, and think about how a sound behaves and evolves in real life when it's close versus when it’s far away.

Volume: Far Away is Quieter

This may be a patronizingly obvious one, but when a sound is further away from you, it’s quieter than when it’s close to you. But it gets a little murky here, as a loud sound from far away could feel louder than a quiet sound close to you. When keeping depth in mind, remember that it’s all relative, and volume alone isn’t a good enough indicator.

Using faders to start to get a sense of depth

EQ: Far Away is Duller and Low-Passed

As a sound gets further away, its frequency profile changes, with high frequencies getting reduced thanks to both air absorption and more directivity at the source. Instruments that are far away start to lose their clarity and presence for this reason. Put simply: a gentle low-pass filter lends a sense of distance to a channel, and a lower cutoff frequency makes for a further-away feel.

Adding a low pass filter to make a source sound more distant

Low frequencies could also be reduced as a sound gets further away, but in the real world they can come and go, varying depending on the source sound and the environment.

Reverb: Different Properties for Further-Away Sounds

There’s no obvious way to set up your reverb to portray something being closer or further away, unless your reverb has a way to explicitly set the position of the sound source.

Piano with reverb

As a rule of thumb, a sound with a higher reverb mix (‘wet’ mix) should sound further away than one set more dry, since a sound closer to you will have a more audible direct sound. Pre-Delay is often used to make a sound feel more close-up, putting an audible gap between it and its reverb, but this might actually have the opposite effect if your reverb simulates a particularly large space.

Dynamics: Emphasize Details for Closer Sounds

If you imagine hearing something in the real world, when an object is closer to you, you can hear every part of it; but when a sound moves further away, all the finer details blend and mix into one sonic mush. The way a mixing engineer might be able to emulate these things is with dynamics.

Piano with compression

Compressors can bring out details in sounds, especially when used for upward compression, which brings lower-level sounds higher up. A slightly different but close solution would be to use a maximizer such as L3, which was formulated for exactly this purpose, only with mixing in mind rather than simulating real-world conditions.

Making a Piano Sound Further Away: Worked Example

In this example, we’ve got a basic, modest backing track that contains a piano part. That piano is quite neutral to start with, but with a combination of theory and experimentation, we’ll experiment with moving it in a purely front-to-back manner. Here’s the original backing with the piano ‘straight out of the box’.

If we take the first principle of depth, volume, to start with, we can reduce or increase the level of the piano to give it a sense of distance. At lower levels, we mimic the quietness of something being far away; at higher levels, we can hear more of the piano’s highs and details.

But this level reduction is by no means good enough to make the piano sound further back. You can still essentially hear it, despite its level change, and there are no more psychological cues to help us ‘get it’.

Let’s continue by adding our next cue: reducing the high frequencies of the instrument. We do this using a high shelf cut in F6. One interesting fact is that the level of the channel output can now go back up somewhat, since the EQ cut is reducing the overall level more than in the previous thing we tried. Here’s how removing the high frequencies sounds.

Next comes a dose of reverb. If there’s anything that can make something sound far away, this has to do a huge amount of the job. In the example below, we’ve used H-Reverb on a send to add that reverb, all while keeping the main channel ‘dry’ output as it was with reduced high frequencies.

Some experiments made with H-Reverb include removing Early Reflections altogether and concentrating on the tail (although this wasn’t worth pursuing in this case), searching for the right Pre-Delay setting (you should always set this to taste based on your specific reverb), and Size (as is customary in a reverb, of course).

Next let’s use our final tactic and increase the dynamic range of the piano to mimic the lack of details that can be heard in a sound source that’s far away from the listener. We can do this quite simply using C1 as an expander rather than a gate. We expand the dynamic range of the piano source sound, the one that goes through all other effects that we’ve applied so far.

After this, once again we have to increase the level of the piano in the mixing console, due to the effective level reduction of the changes we’ve made in our search for depth – something that only reassures us that things have gone to plan.

Depth Was Part of Mixing All Along…

After working on these concepts and going through a real mixing example, things become a little clearer. This struggle for achieving depth – even though we can’t always quite say what we mean by it – has led to some pretty standard mixing techniques being used.

We’d like to argue that today’s standard mixing techniques have been arrived at partly because they satisfy this need for depth in the mix – despite it not being a simple and obvious control on any mixing console.

The techniques we used above take in filtering, shelving, reverb balancing, compression and gain staging, which are all fundamental parts of getting a mix right to begin with. By looking at the mix through the angle of depth, we may have done a lot of the same things, but we’ve been doing so with a context that helps us to make observations and decisions with a real goal in mind.

More on Mixing Techniques

There’s a lot more to learn, from the very basics to advanced techniques on the Waves Blog. Check out our articles on everything from compression to vocals, and learn how to put the plugins in your current Waves Ultimate subscription to better use.

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