RK-12 Microphone Capsule
The Original RK-12
The RK-12 is an edge-terminated, large-diaphragm microphone capsule made to reproduce the sound of the AKG CK-12. It is an excellent complement to a modern C12-style tube microphone mod, such as for the Apex 460 or Alctron T-11A, and is a superior choice for any vocal or voiceover microphone.
The only place to buy an actual RK-12 is on this page. The "RK-12" product name is not generic; the "R" stands for Roswell Pro Audio. This product name has been adopted by competitors and scammers. Buyer beware!
Each RK-12 is a dual-diaphragm capsule, suitable for use in multipattern microphones as well as Cardioid-only microphones. Prior to shipping, each capsule is individually tested in a 4m × 4m × 5m anechoic chamber. Matched pairs of RK-12 capsules include paper copies of their frequency charts.
|Capsule diameter:||34 mm|
|Diaphragm diameter:||27 mm|
|Capsule depth:||12.4 mm|
|Membrane composition:||3-micron Mylar, sputtered with Gold|
Two Included Capsule Mounts
Each capsule from Microphone-Parts.com includes a short mounting post with all necessary screws for installation. We also include our proprietary "supersaddle" (which is a perfect fit for the domed pedestal mounts found on many imported condensers).
For recordists building a matched pair of microphones for critical stereo miking, we offer matched pairs of RK-12 capsules. These capsules are matched by both sensitivity and frequency response; the two capsules' sensitivity differences for matched pairs is 0.3dB or less.
We recommend spending extra for a matched pair only when the microphones' circuits are also matched. This is true of our 990B and MP-V57 PCB kits, and the S-12 microphone kit, but is not generally true of any two inexpensive condensers (whether stock or modified).
Contact us if you have questions or would like to discuss the matching process.
The graph below was created by an independent testing laboratory. It compares the RK-12 capsule (MSRP $139) to a competitive CK12-style capsule (MSRP $245 + $24 for the saddle and post), in an identical tube amplifier circuit.
The more-expensive capsule has a flatter response in the vocal frequency range, followed by an exaggerated lift peaking at 10 kHz. The RK-12 has a smoother high-frequency lift, due to the presence boost from 3–6 kHz, and a warmer, fuller low-end response... for about half the cost.