The vocal on one of a client’s album tracks had a faint click at the start of every sung line, and it came from the order of the plugins on the track, with two saturation plugins running before the compressor.
I was helping a client with a larger project, mixing his album, when he mentioned a small detail on one track that was making it uncomfortable to listen to. At the start of each line, as the singer’s words came in, he could hear a little click and a swishing sound. It was subtle, but it didn’t sound right to him.
Listening through the vocal chain
I put my headphones on, connected over Audiomovers and listened to the track myself, and I could definitely hear what he meant. Then I looked at the plugins on the vocal track, and it became clear quite quickly what the problem was. In order, the chain was:
- An EQ taking off the low end, below the range of his voice, to remove unwanted frequencies.
- A Waves Abbey Road tape emulation, adding saturation.
- Logic’s ChromaGlow, adding further harmonics to make the vocal sound richer.
- A Waves compressor modelled on one of the classic LA units, with gain and peak reduction controls plus attack and release.
Both saturation plugins came before the compressor.
They were boosting the harmonics of everything on the recording, so the background noise reached the compressor already lifted along with the vocal.
In the gaps before each line, the compressor was bringing the background noise up. When he started singing a new line, the compressor took a moment to act, something like 30 milliseconds set by the attack, and during that time we could clearly hear the background sound being reduced. What we were hearing was the boosted noise interacting with the level of the vocal as it came in.
Moving the compressor
The solution was to move the compressor up the chain so it sat before the Abbey Road tape emulation and ChromaGlow. Now the compressor was seeing the recording before any saturation, and the gap between the background noise and his actual vocal was bigger. So the compressor didn’t need to work as hard, and it was no longer being triggered in the way that produced the click and the strange transient at the start of each line.
It was a subtle problem and it needed a subtle solution. A lot of mixing help comes down to understanding how the audio moves through the plugin chain, so you can work out where an unwanted sound is coming from and change the chain to sort it out.
When saturation sits before a compressor, the compressor reacts to everything the saturation has lifted, noise included, so it’s worth trying the compressor before the saturation and listening again.
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