Phase Mindfulness

Ken “Pooch” Van Druten: Mic selection and placement are the most important things to keep drum sound present in your mix. We mic things individually, but remember it’s a kit. The whole thing is the instrument. Drums are generally the only place on stage where there are many microphones in close proximity to each other.

Having 20 open mics picking up the same source from different distances is a phase nightmare. I try to make mic choices and placements so that I don’t have to use any EQ, or at least very little. There are already have multiple sources being summed together, so you don’t need to introduce more phase shift-creating EQ into an already difficult phase situation.

Choosing tight-patterned mics and close miking can prevent a lot of headaches. The first acoustic to electric conversion is key, and where it’s getting that information is most important. Get off your rear end, go to the stage, and move microphones. Often times moving a mic makes the difference between a great sound and a mediocre one.

Ryan John: Because drums are one of the few instruments we capture with many mics, phase and polarity coherence plays a large role in the sound. To optimize the coherence I tend to place overheads equidistant from the center of my snare; this way the snare sound hits both at the same time and is centered in the stereo image.

From there I individually delay (in samples, not milliseconds) the two snare mics to the overheads, and flip polarity as needed, and then delay all other close mics to the closest overhead, and flip polarity as needed. Since I typically have gates on almost all of the close mics, this just means that when a snare or tom is hit, it’s in 100 percent positive coherence with the overheads.

Doing this sounds time-consuming, but it doesn’t have to be: just hit record, and get someone to hit each drum once, measure the delays in Pro Tools, type them into your channel delays, and voila. It’s also pretty awesome to be able to A-B the sound just to see if it’s actually improved, or to snapshot the delays to make the drums seem closer or farther away on a song-to-song basis.

Andy Coules: Dual-mic techniques are commonly used on both kick drum and snare to get a fuller sound, but they should be approached differently to avoid phase issues. In the case of a top and bottom snare configuration, if the mics are equidistant from the top skin, the sound will arrive at both at the same time but the waveform will be inverted on the bottom mic (because as the drum skin moves towards the top mic it moves away from the bottom mic). Therefore you can correct any issues by using the polarity invert switch on the channel (which is sometimes incorrectly called the phase button).

However, with two mics on the kick, the sound will hit them at different times (because of their differing distance from where the beater hits), causing phase issues due to the timing delay. In this instance, delaying the mic closest to the beater will enable you to align the two signals. Since the smallest channel delay many digital desks allow is 1 ms, try to ensure the two mics are 13 inches apart (as this is the distance sound travels in 1 ms).

Sometimes when you bring up the overhead mics in the mix, you may notice that the snare moves slightly off the center of the stereo image. This is because the snare typically sits off center in the drum kit, which not only messes with the stereo image commonly used in rock and pop (i.e., the kick and snare in the middle with the bass and vocals), but it can also cause subtle phase issues in the drum mix (as the loud snare signal arrives at the two mics at different times).

The way to avoid the problem is to imagine a straight line linking the kick and the snare, and then position the overheads equidistant from this line. It might look a bit odd but will ensure your snare is slap bang in the middle of the drum mix. (I often have to tell house engineers to not “correct” my overhead positioning.)

Jonah Altrove: It’s a good idea to make sure that all kick and snare signals are in polarity with each other, so they all move the loudspeaker diaphragm in the same direction if the drummer hits both kick and snare at the same time.

The Inevitable Singing Drummer

Ales Stefancic: If the drummer is a singer as well, I first take care of the vocal before touching the drum mics. If I go the other way around, bringing up the vocal mic would influence the drum sound to such an extent that I would have to go back and re-shape the drum sound around the vocal.

Michelle Sabolchick Pettinato: When a drum vocal is involved, pay attention to how it affects the sound of the snare. The position of the vocal mic in reference to the snare can sometimes create some weird phasing with the top and bottom snare mics. When I’m using a drum vocal (which I keep muted when the drummer isn’t singing), I sometimes need to kill the bottom snare mic to prevent the snare from losing some of its presence or sharpness in the mix. I also will flip the polarity on the drum vocal mic.

Editor’s note: This article is part of a collection of drum-related articles from the June 2018 issue of Live Sound International. Read the rest of the stories here.

Have a suggestion for a future Roundtable topic? Send ideas to editor Keith Clark at kclark@prosoundweb.com.