If you own a Royer R-series microphone, you own two microphones. Most people only ever use one of them.
At distances of three feet and closer, the back side of an R-series ribbon has a slightly brighter response than the front. That goes for every current R-series model: the R-10, R-12, R-121, R-122 MKII and R-122V. The difference is subtle. It is also free, takes about ten seconds to try, and is often exactly what an acoustic guitar or a vocal is asking for.
Here is the same acoustic guitar part recorded twice on one R-121: once on the front, once on the back. Both takes are a Taylor 512 with the microphone eight inches off the twelfth fret. Nothing else changed.
Listen: John Jennings, forward R-121 and backward R-121, matched for level. Switch between the two while it plays.
The second step matters. A figure-8 microphone picks up equally from both sides, but the two sides are opposite in polarity: the front is positive, the back is negative. Reversing polarity at the preamp makes the back behave as the front. If the ribbon is your only microphone on the source you may never notice the difference. The moment you combine it with another microphone or a DI, you will.
Acoustic guitar. Put the microphone eight to twelve inches off the twelfth fret, with the ribbon aimed toward the sound hole. The same approach works well on mandolin and fiddle.
Vocals. Set a pop filter three inches or more in front of the microphone and have the singer start six to eight inches away. Adjust from there. For a large, very warm sound, bring the singer in closer until the proximity effect becomes noticeable. Always use the pop filter.
The front, logo side of the microphone is the side designed to handle very high sound pressure. We do not recommend using the back for loud, close work such as a microphone right up against a guitar cabinet.
Strong singers behind a pop filter, and aggressive acoustic playing, are no problem for either side.
And the effect only exists up close. Beyond about three feet, both sides of the microphone record exactly the same.
This comes from our patented offset ribbon design, found only in Royer R-series microphones. The ribbon sits slightly forward of the center of the microphone, closer to the logo side. That gives the ribbon more room to move backward when it is hit with high sound pressure, which is a large part of why an R-121 can sit in front of a loud amplifier.
The brighter back side was a happy accident. Because the ribbon is offset, it sits in a different position relative to the chamber of the microphone depending on which side faces the source. Turn the microphone around and that difference in position becomes a difference in sound.
Record one pass on the front and one on the back, matched for level, and listen to them in the track. You will know within a few bars which one the song wants.
More recordings made on the back of an R-121 are in the Audio & Video Library, including sessions with Shawn Sullivan, Robert Cray and Alison Brown.