Walk into any concert hall – and look up. How many microphones do you see? Most venues have a stereo pair (that’s two) hanging in front of the stage somewhere. This ubiquitous arrangement can achieve amazing results, and its simplicity allows for a very fast archival of a live event. Choirs, pianists, solo instrumentalists and singers are all usually served well by a stereo pair of microphones.
But when it comes to the drum set, bass, guitar and/or keys, the two-microphone approach is often less than complimentary. Considering that the term “rhythm section” implies there is another battery of instruments somewhere in the vicinity, two microphones begin look even less likely to be up to the challenge of adequately balancing a great diversity sounds.
As soon as the concept of the rhythm section comes into play, so does a long and well documented tradition of what listeners expect it to sound like. Several elements (bass drum, snare, and bass guitar) are most commonly centered in the final mix: equal parts in both speakers. But it’s even more than that. A distant washy equal balance doesn’t cut it. The bass guitar should be centered… AND mostly “dry” (free from excessive ambience). The bass drum and snare are usually treated similarly. If the recording is being made with only two microphones, “centered” means the point in physical space that is equidistant between the the two microphones. And you can’t really have the bass guitar and bass drum occupying the exact same physical space.
In addition to the space issue, there are those other pesky musicians who think the rhythm section is really there just to accompany them. So they’re going to want to be front and center, too, not lurking around only the left or right speaker. Let’s take each group one at a time.
The “Other” Guys
The other guys might be a big band with trumpets, trombones, and saxes. Could be a percussion ensemble full of marimbas and vibes. Maybe it’s a vocal jazz choir. In a recording session, these guys can often still be captured with their own dedicated stereo pair of mics. There are several stereo recording techniques; all of them have strengths and weaknesses, but any of them are capable of producing good results. If space permits, the rhythm section may be able to set up directly behind the other guys. Then any sound bleed from them into the first stereo pair will still be mostly centered – even if it is very faint.
The Drum Set
The most common, simple approach to close miking drums is with 3 microphones. A stereo pair 4-6 feet above the snare (probably in XY position) pointing straight down keeps the snare in the middle, while allowing toms and cymbals to spread across the stereo image from left to right. A third mic on the bass drum provides more control over the low/high drum set balance.
Taking a direct line from the pickup is pretty simple and common. So is using one mic on the speaker cabinet. If you have the time and inclination, do both. With two signals from the bass, the engineer can experiment with volume balance between the signals as well as equalizing signals differently. Options are never a bad thing.
Yes, the Shure SM-57 on the grill of the amp works for jazz too. The bass pickup trick is less useful with the guitar, because the amp is such an important part of guitar tone. Any amps being used might function best aimed out into the abyss of a big room and away from other microphones. If you’re counting, we are up to either 7 or 8 microphones and/or direct lines at this point. Set levels for each mic and you’re off to the races.
I like to start with the other guys’ mics. I want to bring that pair up to a good level and see how much rhythm is bleeding through. Then I’ll bring up the drums until I am confident I have just barely crossed the threshold into acceptable percussive definition. Then up comes the bass to the same approximate level, and then the guitar. After a while I’ll mute the rhythm section, to see how drastic the difference is. I might then see if I can get away with a little less rhythm section than I initially thought. I’ll also do this with the bass by itself. After I’ve played around with levels for a while, I’ll take a long break. Maybe get lunch. Then I’ll come back and see if the balance still strikes me as acceptable after I’ve given my ears and brain a respite.