Used it for live on different Guitar amps and compared to the SM57, MD421 and the C414. All microphones are fine for this kind of application but the Royer gives a bigger and opener sound than all others. Definitely my number 1. In studio it is often used for brass sections.
I also used it for Cello, oboe and clarinet recording and loved it. For the flute it missed some high end but with a little eq that was ok.
On vocals it works fine if you're looking for a dark sound.
The Royer Labs R- 121 mic is a weird looking device in my opinion but that doesn’t mean the sound isn’t good. with a permanently polarized 16-mm (0.63")diaphragm element and a preamp that requires 48V phantom power. It is built using a chassis for a large-diaphragm mic, i.e. a cylindrical box normally used for mics with diaphragm diameter of 25mm (1") or more 16-mm diaphragm size does not allow one to put it in the true large-diaphragm mic category (More on why later). It has an almost flat frequency response from 20Hz to 20kHz and cardioid pattern, but has no bass-roloff switch or 10dB attenuation pads. Comes with a pivot stand rather than a shock mount.
Overall the mic sounds very decent for the money. A couple of observations. In my experience the mic meets the frequency response specifications and even exceeds the given range (picks up to about 23kHz). The mic is tailored for closer recording than regular studio condensers: 6" to 8" rather than 12" from source. It has almost no proximity effect when used on vocals but substantial proximity bass boost when used on acoustic guitar (which you have to remove with EQs since it has no bass-roloff switch).
Acoustic guitar and vocals sound very natural, guitar sounds very good with pick/strumming noise adding a nice bright touch to the recording. It sounds decent on shakers but would not be my first choice for that. I've had some problems removing excess boominess from the bass since with guitar it does get bass-heavy, but the overall quality is commendable. Lack of shock mount and bass-roloff switch I'd say are where R 121 cut quality to make the mic cheaper.
The permanently charged diaphragm, it sounds comparable to the true condensor mics if not better. But electrets may lose up to 3db gam over a few years as the material charging the diaphragm gradually gets de polarized. Hope fully this mic can hold up.
The Royer Labs R-121 is a ribbon microphone designed for use in professional recording studios. Being that it is a ribbon microphone, it is pretty delicate and I definitely wouldn't recommend using this outside your studio. It has the classic look and design made famous by the old Bang and Olufsen microphones. Since it is a ribbon microphone it is suitable for a number of different applications, but it also has some limitations when it comes to what it can handle. This being said, this ribbon microphone is pretty sturdy and can handle more sound pressure level than most other ribbons. The shape of the microphone is unique and makes it easy to place in tight places and to get interesting microphone placements in general.
I've been using the Royer Labs R-121 for about three years. To me, it is one of, if not the best ribbon microphone that is still made new today. Royer has a reputation for making great ribbon microphones, and the R-121 is one of their best models. I have used this in a number of different situations, mostly using it for recording guitar amps and acoustic instruments. It has a unique tone that cannot be achieved with a dynamic or condenser microphone. Besides some of the old RCA ribbon microphones, like the DX77, this is really one of the best ribbon microphones you can get. I would also compare it to another Royer model, the R-122 as they are similar in look and overall sound. Both are great options, it just depends on your budget and what you envision yourself using this for. Of course it isn't cheap as it is made at an extremely high quality and has an awesome tone to it. For the professional engineer, these can be a must have and are a reasonable price for a microphone of this caliber.
This is one of the finest ribbon mics that money can buy. It has an upgraded version by Royer, the R-122, but this one does sound almost as good. Traditionally ribbon mics are regarded as very fragile mics that you wan't to keep away from very high SPL's. However, the great thing about Royer designs is that they can take very high volumes with no distortion or risk of damaging the ribbon. I believe the cap on this mic is around 135dB. If you haven't used a ribbon mic, you don't know what you're missing! Ribbons provide a very, very realistic tone. They seem to react to sound much like human ears do, because if you have a good pair of monitors there doesn't seem to be that much difference between how you hear your sources and what this mic can put out. The top end on this mics is absolutely silky smooth and never harsh. A couple of favorite uses for the 121 are guitar cabs and horns, but in practice you will be hard pressed to find sources that don't sound great through this mic if they sound good in the first place. It connects with a standard XLR cable, and doesn't need phantom power. In fact I believe phantom power will damage the mic, so be careful not to accidentally engage it. This mic also has another advantage of having a different frequency response on the back. When you are close miking something using the back of the mic, the source is a little bit brighter. Saves you the time of adding a top end shelf!
I have had one of these for almost 10 years. I love this mic! I have the 121 and the 122, and I use them in nearly every session. If you have background singers, try setting one of these about 5 feet in front of them. It sounds like they're all right in front of you! I definitely recommend getting this mic if you are serious about getting very realistic sounds in your studio. It costs over a grand, but it is money well spent for the discerning audiophile.