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Core Sound TetraMic
Introduction: TetraMic Single Point Stereo & Surround Sound Microphone

(Last updated 06/20/2019)

May 5, 2019: We've reduced the price of TetraMic! Please see the Online Ordering page for details.

May 5, 2019: We've reduced the price of TetraMic! Please see the Online Ordering page for details.

Core Sound is pleased to offer its groundbreaking TetraMic, the first portable, single point, stereo & surround sound Ambisonic soundfield microphone to be available for under $1000 (TetraMic alone), or under $1350 fully configured for most multi-track recorders and audio interfaces. Individually calibrated, each TetraMic is the finest performing microphone of its type in the world. Compare its performance to similar soundfield microphones selling for $3000 or more and you'll be quite amazed.

Each and every TetraMic is individually calibrated and comes with its own calibration files. All other first-order ambisonic mic from major manufacturers use a single generic calibration file for all of their microphones.

Based on the principles of Ambisonic recording developed by Michael Gerzon and Peter Craven during the 1970's, TetraMic allows you to place a single exceedingly accurate tetrahedral microphone in a sound field, record four channels of audio in "A" format, transform them using software into "B" format (W, X, Y and Z), and later interpret those four channels to essentially any single-point configuration of microphones:

  • omni
  • sub-cardioid
  • cardioid
  • super-cardioid
  • hyper-cardioid
  • figure-8
  • multiple combinations of those including:
    • Blumlein (two crossed figure-8 microphones in the azimuth plane))
    • Height-enabled Blumlein (three orthogonal figure-8 microphones)
    • M/S (Mid/Side)
    • XY (two crossed cardioids) separated by any arbitrary angle
    • binaural, using HRTF information
    • Three hypercardioids facing forward and two cardioids facing rearward (for 5.1 surround)
    • any combination and arrangement of microphones for surround sound or other effects

The apparent orientation can be rotated, tilted, tumbled or zoomed at will.

The four channels of "B" format can also be interpreted into almost any playback format, including:

  • mono (without "sum to mono" phase cancellation issues)
  • stereo
  • binaural, using HRTF information
  • four speakers arranged as a square or rectangle
  • six speakers arranged as a regular or irregular hexagon
  • 5.1 (ITU)
  • 7.1
  • 10.1
  • any of the above plus height information (e.g., two hexagonal arrays of speakers, one above the listener and one below)
  • and many, many more.

In addition to modelling any number and type of coincidently positioned first-order microphones, you can model spaced microphone arrays (e.g., ORTF) by using more than one TetraMic.

This process allows your audio projects to have unparalleled flexibility in post-production.

How good a microphone is TetraMic? We believe TetraMic has the flattest and most extended fig-8 response of any commercially available microphone, bar none; so it's among the best Blumlein arrays in the world. Its free-field omni response is not quite as good as a Bruel & Kjaer 4133 1/2-inch measurement microphone; it's only as good as the wonderful DPA 4003 that we use for calibration -- i.e., sensational! However its diffuse-field response is better than the 4003. This combination of capabilities makes TetraMic one of the world's finest microphones.

When used as an acoustic sensor to locate sound sources in space, TetraMic is capable of resolving angle-of-arrival to five degrees or less, over all three spatial axes. This is better performance than any competing sensor.

Until now, a tetrahedral Ambisonic microphone and its associated electronics cost over $4000 and sometimes as much as $7000. TetraMic is priced under $1000 including its processing software. And its angular accuracy performance surpasses all other microphones of its type.

TetraMic is more than four microphone capsules on a tetrahedral mount. Building a TetraMic starts with a large batch of carefully assembled microphone capsules, pre-selected for sensitivity and frequency response. Each capsule is then exhaustively tested for sensitivity, frequency response, directivity pattern and other parameters. We select four well-matched capsules and confirm their compatibility. Then another round of exhaustive testing begins, this time for the complete tetrahedral assembly. All in all, each TetraMic undergoes more than seven hours of assembly, testing and calibration. Each TetraMic exits the test phase with its own calibration and correction files, used with VVEncode plug-in to ensure that each TetraMic is a fine example of one of the best sounding microphones in the world.

VVEncode on PCs and Macs

To ensure that TetraMic is the finest sounding Ambisonic microphone in the world, it is supported by a custom version of David McGriffy's fine VVEncode encoder plug-in. software. With design assistance from some of the world's experts in Ambisonic microphone design and testing (including those involved with the original commercial Ambisonic microphones), VVEncode performs detailed equalization based on both individual capsule-level and fully integrated TetraMic-level calibrations. It includes functions for A- to B-format encoding and configuration for upright, inverted and two endfire orientations,

VVEncode outputs B-format in the world-standard ambiX format and operates on PCs and Macs.

For real-time processing you would use the VVEncode and any industry-standard VST (or AAX) decoder plugins with your recording software. VVEnode perfroms A- to B-format transformation using the calibration data for your TetraMic. The decoders create virtual microphones and configure the output for different playback configurations. VVEncode operates with any recording application that can use four-channel VST or AAX plugins (e.g., Pro Tools, SONAR, AudioMulch, Plogue Bidule, Wavelab, Cakewalk, Cubase, Samplitude, Ableton Live, Nuendo, Reason, FL Studio, Sound Forge, Nuendo, Reaper).


Fons Adriaenson's powerful and great sounding Linux-based TetraProc application can be found here.

AMBDEC can be used for playback under Linux. For details see the Ambisonia Wiki (www.ambisonia.com) and search for AMBDEC.

Jack and Ardour also work fine under Linux.

TetraMic Sound Samples

You can find a variety of recordings made with TetraMic at www.ambisonia.com . Charles Veasey (user name: cveasey), Paul Hodges (pwhodges), John Leonard (soundmanjohn), Hugh Pyle (hughpyle), and Len Moskowitz (LenM) have posted recordings made with TetraMic.

All can be downloaded as B-format files, to be played back on any ambisonic player. Most can be downloaded as stereo and 5.1 files too.





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Listen to Ambisonic Recordings


For pre-sales consulting or to place an order, call Core Sound at 1.888.538.6744 or 1.201.801.0812.

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"Core Sound" is a trademark of Core Sound, LLC
"OctoMic", "TetraMic", "HeadLine" and "2Phant" are trademarks of Core Sound, LLC
Thanks to HK Audio for use of their open-air concert photo. Mossman photo ©2004 OceanBridge Communcations.
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