Resonance is one of those things that plagues audio professionals – from acousticians to ADR recordists to live sound engineers. Those of us who spend our time in the studio aren’t an exception to the problem.
Despite having well designed rooms built by experts, major studios have worked to fight resonance for years and continue to still today. They put up blankets and gobos to create isolation between instruments because they know that a note played by one musician might resonate with something else in the room. Eliminating this during tracking is essential if you want to start from a clean, clear slate going into mixing.
But you can’t just stop there – resonance sometimes doesn’t present itself during tracking. Often, it’ll appear in such a minor capacity that you’ll only start to notice it after adding some compression or limiting.
When you find yourself in this situation, are you able to identify the resonances that can ruin your mix?
Starting With Your Singer
A singer’s voice is all about resonance. In fact, many instruments are sonically defined by the way air moves through them and how that air resonates, but with singers, we should be paying close attention.
Often, problematic resonance with a vocalist either comes from their technique or the space they’ve chosen to record in. A room without proper treatment can be extremely reflective, causing louder notes to bounce all over the place. Eventually, they’re bound to hit a note that vibrates just right with a makeshift vocal booth.
Fortunately, treating this is as simple as putting up something to break up standing waves in the room. Reflection filters are somewhat effective as is wall treatment, but truthfully a packing blanket may go just as far to deaden the space enough to work with.
If you’re finding that the resonance within a vocal performance presents itself inconsistently as you mix, the room likely isn’t the issue at all. Instead, it may be the singer’s technique or the equipment they’re using. Cheaper microphones use components that may not have the flattest frequency response and as a result resonate more with certain notes than others. Likewise, a singer may naturally sing certain notes louder than others.
In either case, the best solution is some spot EQ that notches out the problem frequencies. Once identified, you can either cut that range with a narrow EQ band or automate it to dip the frequency only when the note is hit (working a bit like a de-esser).
Resonance In Rhythm Guitars
Rhythm guitars are another category where resonant issues can derail a mix if not caught and treated. With a resonant rhythm problem, you may find that the issue isn’t with any specific track. Instead, the issue can sometimes present itself only when they’re summed together.
We see this a lot with double-tracked guitar parts where the notes are identical. As you stack chugged rhythm guitar parts together, the low mids start to feel tubbier – growing exponentially from a sonic perspective. While this can be great for creating massive sounding guitars, it’s not so great for the bass they’re masking or the balance of the mix.
The same approach can be taken here with EQ as we recommended for vocals, but with these types of issues, professional mixers are much more likely to reach for multi-band compression or other compressors that can target and treat the low-mids of their guitar bus explicitly.
The result is often a tighter, more controlled guitar mix without sacrificing any of that power or presence that double-tracking allows us to create.
Resonance In Bass Drums & Floor Toms
What would our resonance checklist be without an appearance from our drum kit?
As anyone who’s ever stuffed a pillow in their kick drum or who’s taken measures to deaden their drumheads can attest – acoustic drums love to resonate. Not only that, but they’re loud.
Of note, floor toms seem to ring out the longest when they’re hit, and kick drums are the most susceptible to resonance caused by other instruments (with snare drums taking a close second). With so much happening in and around our drum kit, it’s easy to understand why issues occur, but it’s not as clear how you should address it.
From my perspective, the best we can hope for in the studio is good isolation and good recording techniques (this especially means mic placement). Getting those two things right make drums pliable in the mix; they won’t eliminate resonance altogether, but they give us a fighting chance.
From there, it’s a matter of cleaning up what we don’t need and making room for what we do.
Kick drums have a surprisingly little amount of frequency content needed to sound great – give the low end and an upper mid boost and they’ll usually turn out great. As a result, you can often scoop the lower mids where resonance can occur to make room for other things.
On floor toms, simply adding a high-pass filter can do the trick. You don’t need to set it super high or roll off a lot – just setting the threshold high enough to free up the low end for bass and kick goes a long way. In fact, this is a strategy you could be using throughout your mix if you need more space for either instrument!
Bonus Category: Bass
I went back and forth on whether to include bass on this list because it’s not something that’s usually as easy to treat as the other items. Bass resonance is a problem in some mix situations, but the fix is rarely as simple as removing a single frequency range with EQ – it requires a more comprehensive approach to bass mixing.
If you’re finding that your bass mix has got you in a rut, check out our Basscrusher eBook. It’s got over 80 pages of bass-focused recording, mixing, and mastering techniques that tell you everything there is to know about getting a good, balanced bass tone in your mix.