RK-47 Microphone Capsule

The RK-47 is our original and most popular capsule. It is a recreation of the historic K47 capsule found in the Neumann U47, and serves as a nearly universal fix for over-bright condenser microphones.

The K-47 is the cure for inexpensive imported microphones with hyped high frequencies. Many of the microphones made in China, and nearly all the inexpensive ones, use a copy of the Neumann "K-67" capsule.

The original K67 is a wonderful design, and it can be found (with subtle variations) in the vintage Neumann U 67 and every U 87 ever made. But the K67 capsule design has a sharp high-frequency peak that was intended to be paired with corrective EQ in the mic's circuit. Most inexpensive condensers copy the K67 capsule, but not the corrective EQ. The result is an overly bright, peaky-sounding microphone. These can work fine on some applications. But if that's what all of your microphones sound like, you're probably ready for something new.

Enter the K-47. This microphone capsule was also designed by Neumann. In fact, the K47 capsule is the heart of Neumann's most famous microphone, the U 47. The K47 capsule has a flatter frequency response than the K67, making it a fantastic upgrade path for over-bright Chinese condenser microphones.

Introducing the RK-47

We are proud to announce the RK-47, a true single-backplate dual-diaphragm microphone capsule modeled after the legendary K47.

Each RK-47 capsule is individually tested in an anechoic chamber prior to shipping, to ensure that its frequency response meets our standards.

The RK-47 capsule is compatible with most large-diaphragm condenser microphone designs. It should be easy to install in most of the large-diaphragm condensers made by MXL, CAD, Studio Projects, Avantone, Nady, Apex, BLUE, etc.

All RK-47 capsules are dual-diaphragm, and can be used in both multipattern and fixed-Cardioid microphones.

Capsule Mounts Are Included

Each capsule from Microphone-Parts.com includes a 10.5mm mounting post with the saddle appropriate to the capsule. We also include our custom "supersaddle," which mounts easily to the existing mounting post (including most domed pedestal mounts) in popular microphone models. All screws are included, as is the backplate termination wire to be attached during installation.

Matched Pairs

For recordists building a matched pair of microphones for critical stereo miking, we offer matched pairs of RK-47 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 matched pairs only for microphones whose circuits are also matched. This is true of our 990B and MP-V57 PCB kits, and the RA-23 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.

Frequency Response

The graph below shows an MXL 2006 (red line) versus the 2006 with an RK-47 capsule installed (black line).

This is representative of the sort of sonic change you can expect from installing the RK-47 into most typical Chinese condenser microphones. The black line represents the modified microphone. It shows that the RK-47 revoiced the microphone in the following ways:

1. The lows are fuller below 150Hz.
2. The modded microphone has a broad presence peak in the musically useful range between 1kHz and 8kHz.
3. The sharp high-frequency peak at 14kHz is gone.

The result: the modified microphone is warmer, more articulate in the mids, and lacks the piercing, hyped, over-bright sound of the original.