RK-12 Microphone Capsule

$ 169.00

Shoppers beware: Capsules called "RK-12" being sold by any other company are counterfeits. See additional info below.

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 tube/transformer mic circuits, and is a superior choice for vocal recording.

Beware Counterfeits and Knock-Offs

We developed the RK-12 in 2011, and have been the sole official source of it since then. The low-cost "RK-12" capsules sold via Reverb, Ebay, Ali Baba, and unscrupulous competitors' websites are not the same capsule. They lack the accessories, documentation, warranty, support, and most importantly, the sound of our RK-12. Buyer beware. The samples we've tested from these suppliers had thin bass, low output, goofy frequency responses (+5dB at 3kHz?!), short wires, and noise problems.

The "R" in "RK-12" stands for Roswell Pro Audio, which we own and operate. Now you know something about the RK-12 that all the scammers and counterfeiters do not. :-)


The RK-12 is backordered until November 7, 2023.

Capsule Description

Each RK-12 is a dual-diaphragm capsule, suitable for use in multipattern microphones as well as Cardioid-only microphones. Each RK-12 capsule is individually tested for sensitivity and frequency response.

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 RK-12 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).

Matched Pairs

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 difference (measured at 1kHz) is 0.5dB or less. Frequency response for all four diaphragms varies by 1.5dB or less.

Contact us if you have questions or would like to discuss the matching process.

Frequency Response

The graph below was created by an independent testing laboratory. It compares the RK-12 capsule (MSRP $169) to a competitive CK12-style capsule (MSRP $289 + $25 for the saddle and post), in an identical tube amplifier circuit.

The RK-12 has fuller bass and a smoother high-frequency lift, at a lower cost.

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