The majority of vocalists don’t know how to use a mic, and what is worse is that a lot of engineers don’t know how to teach them to use a mic. As you’d imagine, the outcome sounds pretty bad. That’s the most irritating scenario for me. I find sibilance is very harsh, and it can be easily tamed in the early stages using the proper mic and technique for a certain vocalist. Sometimes you need a de-esser in conjunction with a compressor/limiter, and of course, using the best-sounding A/D converter possible is key. I know a lot of these lower-price rigs don’t give you that capability, but as a sound engineer, you need to strive to get the best you can possibly afford – and in some situations, less is more. Adding a lot of EQ after the fact rarely helps the recording.
Another thing with vocalists is pops. I find that because the vocal is usually one of the loudest instruments in a mix, you have all sorts of odd sounds that are normally filtered through the air when someone speaks without a mic that get captured during recording. It doesn’t help that the mic is often placed at the worst position – the jaw – so all of these bad sounds are directed directly into the diaphragm.
There are other things I could mention, but for time’s sake, I’d say those are two dreaded instances for mastering engineers.
George Graves is a Mastering Engineer at Toronto’s Lacquer Channel Mastering carrying over 40 years of industry experience.