Ribbon Mic 101
By Sarah Jones
The December issue of EQ profiles Elvis Costello's new album, National Ransom,
which was recorded largely with vintage ribbon microphones. Here, learn
more about the design and function of these unique dynamic mics.
ribbon microphone is a unique type of dynamic microphone that is based
around a thin, corrugated strip of metal (often aluminum) or film
suspended between two magnetic poles. Unlike traditional moving-coil
dynamic mics, the ribbon element responds to variations in the velocity
of air particles, rather than the pressure
As the ribbon vibrates within its magnetic field, it generates a tiny
voltage that corresponds to these changes in velocity. In classic ribbon
designs, this level is very low compared to typical dynamic mics, and a
step-up transformer boosts both the output voltage and impedance.
Preamp choice is very important when using ribbon mics.
ribbon mic has an extremely thin, delicate element, it is capable of
capturing fast transients. Ribbons mics have a wide dynamic range, and
are capable of handling high SPLs at high frequencies. (Give them a try
on brass or percussion.) These mics are bidirectional by design,
because the ribbon element responds to sound arriving from the front or
back of the mic, and does not pick up sound arriving on its sides. This
natural figure-8 pattern makes them ideal for stereo recording
applications, and is useful in applications where you want to eliminate
unwanted noise between two sources (i.e. in broadcast).
mics are very sensitive, but they are often quite fragile; delicate
older models can be broken by strong gusts of air, voltage spikes or
even by being stored on their side.