Mixing tricks

This brings us to the crux of spectral management. Now that you’ve seen some of the underlying principles, how can you use this stuff for fun and profit? First off, understand that the spectra of instruments overlap and share octave bands. If you have two instruments that both sound really cool when you boost them at 2 KHz., when you combine them in a mix they will tend to fight, to mask each other. So, a little spectrum sharing is in order. If instead of boosting them both at 2 KHz., you boost one of them at 1.5 KHz. and the other at 2.5 KHz., they will tend to blend much more effectively, so that in the mix both can be heard clearly, without clashing. If the timbre of one is critical to you, change the EQ’d frequencies of the other one. Although it may sound less good by itself, it will sound better in the mix and the overall mix will sound better as well.

The organizational principle I use is to prioritize the value of the instruments in the mix, and to allocate key octaves to specific instruments (would you believe, for instance, that I set aside Octaves 2 and 3 for kick and bass respectively, and that I reserve Octave 8 for vocals?). I then figure out what frequency bands are available for the various instruments and how they all sound in those bands, and then allocate frequency ranges to specific instruments. These are usually related to the specific tonal qualities of the instruments. Acoustic guitars with metal strings, for instance, can be clearly evoked (via the metallic picking sound) in Octave 9. Hi-hat is predominant in Octave 10, and little else is there. Various electric pianos have a lot going for them in Octave 6 and 7. Electric bass can really be brought out by boosting around 900 Hz. (pulling up harmonics 8 through 20), without using up critical bass power. Kick drum, believe it or not, has attack energy in Octave 9 that can be used to effectively evoke its power, especially when coupled with Octave 2.

The most important aspect of spectral management in mixing is to hear out the specific frequencies of each instrument, and make sure you aren’t caught up in squatters’ rights battles between the harmonics of the various instruments in your mix. Share the spectrum! Be careful when you boost. Keep your low-frequencies under control. Naturally (yeah, I know -- I say this to everybody!) the most important thing is to keep spectrum in your mind. Feel it, hear it, learn to visualize it as a map of colors and musical qualities that you can use to make your recordings really work! And with that thought, happy mixing!

Dave Moulton is Chairman of the Music Production and Engineering Department at Berklee College of Music. Alex Case attends to fundamentals in the department and Peter Alhadeff is partially there and partially teaching math at Berklee.