The importance of using trim plugins to avoid clipping the mix bus

Have you ever started working on a session and realised that before you’ve begun to adjust levels or introduce any plugins, the master fader has already clipped? Before I knew about trim plugins, I had no idea why this kept happening.

Why is my master fader clipping?

I used to turn down all of the faders to try to resolve the issue. But the problem with this was that using the lower part of the fader made it hard to make accurate changes. Here you can see that using the lower part of the fader means that a small change could make the difference of as much as 10 dB:

Whereas the same change higher up the fader makes the difference of only 2 or 3 dB. Working with a low fader position always seemed like a clumsy approach to mixing. I wanted to be able to use the entire fader to mix with.

Use trim plugins to turn your signals down:

The answer was to turn the signal down using trim plugins (known in some DAWs as ‘gain’, and referred to in ProTools as ‘clip gain’). Just about all DAWs have some variation of this, and it’s really simple to use. Trim plugins allow you to turn down the level of your signal. So adding trim plugins at the beginning of your insert points, will allow you to attenuate the signals. In doing this, your mix bus/master fader should have plenty of headroom and shouldn’t clip. It also means that you can utilise your entire fader on each channel.

In my experience, without using trim plugins, the mix bus will start to clip on 99% of sessions. Now, I include trim plugins as part of the way that I manage all of my mixing sessions. I like to carry out this process as soon as I start mixing. That way I can start mixing with plenty of headroom.

Aim for -18dB RMS:

You may be asking at this point, how much should the signal be turned down by? I usually aim for each signal to be pulled down to around -18dB RMS. I use an RMS meter to measure this. This is important if you’re going to be using plugins that emulate analogue equipment, as they generally have a ‘sweet spot’ at around -18 dBFS. Alternatively, if your plugins don’t have a sweet spot, then just pull your signals down to between -10 dB and -12 dB. This will free up some headroom. Then go through and tweak the level of any signals that are still too hot, or are now too low.

Open up a session that you know has some really hot signals and find your DAW’s trim plugin. Pull the levels of the signals down and see how much easier it is to mix with more headroom!