What goes around comes around. From the 1920s through the 1940s, PA systems for music often used only a single microphone.
Band members would gather closely around this mic, balancing their sound by moving toward or away from the mic. Radio broadcasts and recordings often used one mic as well. And over the past several years, this “old-fashioned” technique is making a comeback.
Many bluegrass and folk bands use the one-mic method with surprisingly good results, typically using a large diaphragm cardioid condenser. It picks up sound with amazing clarity and usually with very good gain before feedback.
How can a single mic work so well? As the theory goes, the fewer the number of open mics, the better the gain before feedback.Also, a single mic picks up all instruments and vocals with a coherent, focused sound. There are no phase cancellations between multiple mics to color the tone or smear the transients.
Want to try the single-mic method? Set up the mic on a stand, ideally in a shock mount. (Use a boom if you need more room for instruments). Place the mic at about chin height and 12 to 18 inches away from the performers. The stand should be positioned in the middle of two or three musicians. If the band is larger, every two people might be allocated a single mic.
In a typical bluegrass or folk group, you’ll see a fiddle, guitar, banjo, mandolin, singers and maybe a dulcimer or bass. It’s possible to get a good balance of all these elements through careful mic placement.
Raise the mic stand to make the vocals louder relative to the instruments, or vice versa. A thing to try is aiming the mic slightly left or right of center to adjust the balance between performers. Some performers and engineers prefer to run the mic signal through a high-quality preamp and then feed the preamp’s line-level signal to front-of-house.
Feedback created by stage monitors is always a concern, and this method helps eliminate the potential for problems. And performers tend to hear each other just fine anyway because they are close together and generally not using guitar amps.
However, lead acoustic guitar players often want/need a monitor to hear themselves. It’s a good idea to start with no equalization, and then tweak a graphic EQ to notch out feedback frequencies.
One obvious advantage of the single-mic technique is that the stage looks cleaner. Gone is the forest of mic stands, booms and cables. Instead, you have a low-tech, old-fashioned look that fits in well with the music.
Setup is much quicker as well: just place the mic, plug it in, adjust position, and you’re done. The band determines the mix, rather than the sound mixer who might not be familiar with the music. Of course, musicians are happier with this arrangement than sound mixers!
However, with the single-mic method, fine control of the mix balance, EQ and effects is given up. The technique works best for small acoustic groups that have a good live balance. Also, sound may be a little thin because you’re not hearing the usual close-mic proximity effect. Some bass boost can help with this. One other disadvantage is that the method is unfamiliar to some house engineers.
It comes down to another theory, one that says air is the best mixer. The single mic capitalizes on this, capturing a balanced blend of all instruments and vocals from one point.
Give it a try, and you just might be delighted with the purity and simplicity of this technique.
AES and SynAudCon member Bruce Bartlett is a live sound and recording engineer, audio journalist, and microphone designer. His latest books are “Practical Recording Techniques, 6th Edition” and “Recording Music On Location.”