Ask the Engineer: Scott Hull on Mixing: Master Buss EQ and Peak Limiting, Part 1

Ask the Engineer graphic

Ask the Engineer is a series on the Masterdisk blog where our engineers answer questions about music production.

SCOTT HULL is a 28-year veteran mastering engineer and the owner of Masterdisk studios in NYC. Scott started his career in 1983 and has mastered hit records and classic albums in every genre, as well as many Grammy-winning titles. He is widely regarded as an expert in vinyl mastering. Recent projects include albums for Donald Fagen, Sting, Dave Matthews, Glenn Frey and KISS, as well as multiple albums for the Sh-K-Boom, Tzadik and Luaka Bop labels. Over the course of his career Scott has mastered albums for Bob Dylan, Bruce Springsteen, Miles Davis, Lou Reed, Ravi Shankar, Herbie Hancock, Tom Zé, John Mayer Joe Bonamassa, and many more.

Photo of Scott HullQ: When I send my mixes to my mastering engineer should I remove the buss limiting and eq?

A: Yes and no… it really depends on how you mix. You have to think about what outcome you’re going for before you can know what will produce the best results. I’ll give you some guidelines.

Mixing through a buss compressor is not necessarily a bad thing. But you have to understand that it is adjusting the levels automatically when it gets loud and in effect the buss compressor is a sort of auto-mix tool. If this is used in moderation, for a specific desired effect, that’s great. However, you have to consider that when you take the buss effects off your mix will change. Sometimes subtly, sometimes not.

Another typical use of a buss compressor or limiter is to bump up the level of the mix for the final level. Some mix engineers wrongly refer to this as mastering. This is like putting a mic on a stand and calling that recording. But that’s a separate subject! Anytime you or your mix engineer places a level bump on the buss you have to ask that a non-limited version is also created… no mater how much the mix engineer objects.

Let’s talk for a minute about the problems with mastering from a maxed-out mix.

The promise that professional mastering can help transform your mix is only possible when the mix is supplied without peak limiting. I prefer no peak limiting of any kind. The peak limiting helps you turn up the level and make the mix louder, but this process makes mastering less effective. I find that it takes more EQ to make things sparkle and it takes even more compression to make the changes needed in mastering when the mix has too much peak limiting.

Basically, limiting the mix simply limits the possibilities of your music and should only be done with great care. Often the mix environment is not revealing enough to judge the positive and negative effects of limiting. For the best sounding product, limiting – as much as is desired – MUST happen last, after EQ changes and any “color” processing like tubes and compressors are applied.

The mix engineer’s job is to supply a mix that will get approved. But the mix engineer should also explain to their clients that the “loud” setting of their project must be determined in mastering. And that mastering cannot effectively be done by the same engineer and in the same environment that the mix was done in.

Next time I’ll list my guidelines for the use of buss processing.

(Read Part Two here.)

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