Jazz musicians tend to give their vocalists a lot of space - and we’re not talking about the distance between them in the studio. Because classic jazz tracks tend to be gentle, textured and soft, it’s a lot easier to pick out the subtle qualities of a singer’s voice. In other words, if a vocal is treated poorly, the listener is certainly going to know about it!
Getting a classic jazz vocal sound isn’t too difficult, provided you stick to a few basic principles. The first thing to be aware of is that you’re trying to keep the singer’s voice as natural as possible. When you do add processing to it, you’re trying to bring out - rather than mask - its natural qualities.
So when you’re adding, say, reverb to the vocal, you’re going to want to stay away from the more intense settings. If you think the listener will be consciously aware of the added reverb, dial it back.
It’s by no means a concrete rule, but try to steer clear of any plug-ins that actively colour the sound. For example, a transparent EQ is better in this case than one that adds its own character.
Better, but again, not essential: as long as you’ve got a decent EQ that doesn’t actually advertise that it adds colour to the sound, you’ll probably be OK.
Compression is a consistently thorny issue in jazz mixing, with some engineers arguing that it shouldn’t be used at all. By avoiding it, they say, the natural dynamics of the performance are preserved. We say, use your ears: if you think your vocalist would benefit from a little compression, go for it.