Acoustic guitar, upright bass, violin, mandolin, banjo – all produce a sweet, airy sound that can be captured with the right approach. Acoustic music heard over a sound reinforcement system is all about beauty and naturalness, not hype.
Listen to a number of well-recorded CDs of old-time country, bluegrass and acoustic jazz. In most cases you’ll hear no effects except some corrective EQ and maybe just a little reverb. Let’s look at some ways to capture that delicate sound and prevent feedback.
Picking It Up
An acoustic instrument can be picked up in multiple ways: with a microphone on a stand; with a miniature mic clipped to the instrument; with a contact mic; with a pickup fed into a preamp or DI box; or with a distant large-diaphragm condenser mic (LDC). A combination of these methods can also prove successful.
A good mic choice for acoustic instruments are small-diaphragm cardioid condenser models. The cardioid pattern reduces feedback, while the condenser transducer captures a detailed, accurate sound, in which you can hear each string within a strummed chord. Of course, the venerable Shure SM57, a dynamic unidirectional (cardioid) does a good job too, especially when feedback is a problem.
Some musicians might prefer a miniature clip-on condenser type like a lavalier. Miniature mics can be directly attached to some instruments if the element will handle the SPL. The advantages are consistent sound from gig to gig, an uncluttered stage, and freedom of movement. The musician is not tied to a single position near a stand-mounted mic.
These can be mounted on guitar, upright bass, cello, and even autoharp. Use easy-release tape like board tape and be sure to ask the permission of the owner before attaching anything to an instrument.
A few years ago, for a traditional bluegrass band that was struggling sonically with the single mic technique typical of that genre, the solution was attaching lavs to the mandolin, upright bass, and the shirts of the guitar and fiddle players. They attained a much better sound, maintained the single mic look, and as a bonus there was more control of the mix.
DPA Microphones offers a range of good solutions for tough situations. The d:vote CORE 4099 condenser is a very small supercardioid that fosters quality capture and is capable of handling high SPL. It’s so low profile as to be almost invisible, with a flexible clip-on system providing fast, stable and repeatable attachment and a flexible gooseneck that can be positioned at different angles.
And by detaching the clip from the gooseneck and re-mounting it turned 90 degrees, the number of mic positions is increased. This mic is a solution with a variety of instruments, such as string and wind instruments, and piano, with a variety of tailored mounting options offered.
Here’s a variation: clip a lav to the musician with the element pointed at the instrument. This proved a winning solution when a violinist who didn’t want a mic clipped to her expensive fiddle, and she also refused to stay near a stand-mounted mic. She was outfitted with a headset mic pointed at the violin. It sounded quite good and there was plenty of pickup.
The Countryman Isomax 2 (I2) miniature mic goes further in providing options for optimal capture of strings. The I2 is available in omni, cardioid, and hypercardioid patterns, joined by a range of available mounts, including ones for violin and viola, cello, bass and even saxophone.
For string instruments, the mount sits securely behind the bridge while offering a lot positioning freedom, allowing the mic pattern to be directed to best capture a natural tone. The mounts are designed to minimize vibration noise, including the use of viscoelastic damping materials to reduce transmitted shocks.