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Q. How do I tackle the unwanted noise coming from analogue modelling plug-ins?

I like to use a lot of analogue modelling plug-ins when I’m mixing, but while I like the sounds I’m getting in general, I always seem to end up with too much noise and it’s driving me crazy! What’s the best way to tackle this problem?

Daniel Jones via email

SOS Reviews Editor Matt Houghton replies: The noise could be coming from more than one place, and could be being amplified by more than one processor, so the first task is to find out where the noise is actually emanating from. Step one is to turn off the noise generators! These seem to be on by default in too many modelling plug-ins. (Really, who wants them to sound that authentic? They’ll be making them break down during sessions and charging a virtual repair fee next!) Step two is to go back and look at the sources you’re processing, to see if there’s any low-level noise there that’s being amplified by the compression make-up gain that’s going on in a lot of these plug-ins. I’m not just talking about compressors and limiters, here — anything that features some sort of saturation or distortion will reduce the dynamic range, and when gain’s applied that will bring up the noise along with everything else.

A common cause of unwanted noise is analogue-modelling plug-ins, which are often too authentic! This UAD Studer model, for example, features a  noise control which, by default, is hidden beneath a  panel. Several Waves plug-ins also have noise switched on by default, and in some mixes compression and limiting further down the signal chain can raise this to annoying levels.A common cause of unwanted noise is analogue-modelling plug-ins, which are often too authentic! This UAD Studer model, for example, features a noise control which, by default, is hidden beneath a panel. Several Waves plug-ins also have noise switched on by default, and in some mixes compression and limiting further down the signal chain can raise this to annoying levels.Then it’s time to consider how to tackle the remaining noise. If noise is prominent while the wanted signal is playing, consider using a dedicated noise-removal tool like iZotope RX, Waves X-Noise and so on. These can be highly effective, but they’ll sometimes leave unwanted artifacts. If the noise only bothers you between sections of wanted sound, then level automation on the individual sources is an obvious solution — if the noise isn’t there, it can’t be amplified by any plug-in.

Gates do this automatically, of course, but they just don’t sound right to me unless they have a variable ‘floor’ control, or whatever you prefer to call it (the bundled one in Cubase, for example, doesn’t have this feature), as the abrupt cutting off of the noise just serves to draw attention to the fact it was there in the first place. I’d rather have noise right the way through than hear that! But even then, level automation is a more precise option.

A more natural-sounding technique than a gate is to automate the frequency of a low-pass filter so that the filter rolls down the spectrum in sections between the wanted bits of sound. The sound remains, but it is less noticeable, and the transition between sections is less glaring too. This is how the old Symetrix noise gates worked, and where sophisticated noise-removal tools such as iZotope RX aren’t called for, or aren’t working for you for whatever reason, it’s a useful technique to try on hissy guitar sounds; I’ll bet it will work for you too.

I haven’t yet found a plug-in that does this automatically for you, but you can do this in Cockos Reaper using its dynamic automation system (it’s called Parameter Modulation; see http://sosm.ag/reaper-parametermod for details). This can be set up to make the filter frequency move dynamically in relation to the amplitude of the source signal — so as the vocal phrase finishes, the filter rolls off the more noticeable high-frequency hiss. It takes a bit of finessing to get it right, but if you’re already using Reaper, it could be just the ticket!

Published January 2015