The inner workings of a ribbon mic; note ribbon element on the right.
A ribbon mic solves a number of specific problems in the studio. It''s often selected for the way it smoothes out harsh, high-frequency artifacts from instruments such as brass, saxophones, bowed strings, and hand percussion. When used on drums and guitar amps, it''s chosen for its accurate, yet punchy sound.
The ribbon itself is a lightweight, ultra-thin, rectangular piece of corrugated aluminum that is suspended within a magnetic fi eld. With less mass to move than a dynamic mic, it offers a quicker response and captures transients very well. Yet the frequency response of most ribbon mics begins to roll off above 10kHz.
CRANK IT UP
As an electromechanical transducer, a ribbon microphone doesn''t require phantom power. In fact, this current can damage passive ribbon mics (although some recent models, particularly high-quality ones, are designed to withstand phantom power). But it''s better to be safe than sorry and keep the +48V button off when a passive ribbon is connected. Active ribbon microphones, on the other hand, have a built-in amplifier stage and do require phantom power. Consequently, they have a hotter output than a passive mic.
Passive ribbon mics require more gain than dynamics and condensers to achieve optimum performance—70dB or more is ideal. Typically, the preamps in inexpensive digital interfaces offer less than 60dB of gain. So if you use one of these, you''ll want to invest in an external preamp for your ribbon. One inexpensive solution is the Cloudlifter CL-1 from Cloud Microphones, a single-channel, phantom-powered preamplifier meant to be used between the ribbon mic and your low-gain preamp. The CL-1 adds approximately 25dB of gain, depending on the mic. Although it requires +48V to operate, the CL-1 doesn''t pass the phantom power through to the mic itself.
AEA, on the other hand, offers a full-featured 2-channel preamp specifically designed for velocity transducers. The TRP (short for The Ribbon Preamp) offers 83dB of gain and includes a highpass filter and phase switch. However, the TRP does not have phantom power, making it impossible for engineers to accidentally damage their ribbon with this device.
WORK WITH YOUR ROOM
The majority of ribbon mics are side-address and have a bi-directional, figure-8 pattern. Notable exceptions are the classic RCA 77, which offers three patterns, and the unidirectional models from beyerdynamic.
When using a bi-directional pattern, the space around the mic becomes an important consideration. The distance between the source and the mic is often determined by how much room sound you want to capture, as well as the volume of the source.
Make sure you don''t place the back of the mic too close to a reflective surface, such as a low ceiling when using it as a drum overhead, or a piano lid when tracking a piano. The reflected sound can color the track in a negative way. This is especially critical if you''re using a pair of bi-directional ribbon mics for a stereo recording in a Blumlein pattern.
As directional mics, ribbons exhibit proximity effect, which causes a low-frequency boost as you move the mic close to your sound source. You can use the increased low end to your advantage in some situations, though it can also muddy the sound. On electric guitar amps, for example, it''s common to put the mic about an inch or two from the grille. If the sound is too dark, try facing the back side of the mic, which has a brighter sound on some models, toward the amp.
Some instruments that sound great when tracked with a ribbon don''t benefit from close-miking, because it enhances negative aspects of the sound—the scratchiness of a bowed string, or the spittiness of a brass instrument. For vocals, start by placing the mic 7 to 10 inches from the singer, and be sure to use a pop filter. You don''t need to get too close, because the mic is sensitive enough to capture every gesture at that distance.
For saxophones and brass, begin with a distance of 2 to 4 feet from the mic. From there, you can adjust the placement to achieve the balance of room sound you want.
A single, high-quality ribbon mic makes a great drum overhead, but the trick is to place it in such a way that you get a good mix of cymbals and drums (while keeping it out of the way of misdirected drumsticks). A ribbon mic also sounds great 3 to 5 feet in front of the kit, about 3 feet from the floor, and aiming at the snare. From there, tweak the position to get a suitable balance of the kit elements.