(Last updated 09/25/2015)
September 25, 2015: We are currently shipping
TetraMics roughly three weeks from receiving an order.
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. It 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.
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
- multiple combinations of those including:
- Blumlein (two crossed figure-8 microphones in the azimuth
- 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)
- binaural, using HRTF information
- four speakers arranged as a square or rectangle
- six speakers arranged as a regular or irregular hexagon
- 5.1 (ITU)
- 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
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
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.
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 "VVMic for TetraMic" and the VVTetraVST VST
plug-in to ensure that each TetraMic is a fine example of one of the
best sounding microphones in the world.
"VVMic for TetraMic", VVTetraVST and VVMicVST
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 "VVMic for TetraMic" post-processing
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), VVMic performs detailed
equalization based on both individual capsule-level and fully integrated
TetraMic-level calibrations. It includes functions for shelf filtering
for improved localization cues, "A" to "B" format transformation, and
decoding for playback in many playback configurations (e.g., mono,
stereo, ITU 5.1, hexagon, square and many others).
For real-time processing you would use the VVTetraVST
and VVMicVST VST plugins with your recording software.
VVTetraVST performs A- to B-format transformation using the calibration
data for your TetraMic. VVMicVST controls virtual microphone and
playback configurations. On PCs, both plugins should work with any
recording application that can use four-channel VST plugins (e.g.,
SONAR, AudioMulch, Bidule,Wavelab, Cakewalk, Cubase, Samplitude, Ableton
Live, Reason, FL Studio, Sound Forge, Nuendo, REAPER). They may also be
able to be used with programs that require RTAS plugins (e.g., ProTools)
by use of a translation layer like FXpansion.
"VVMic for TetraMic" runs on Windows PCs. VVMicVST and VVTetraVST
VST plugins are available for both PCs and Macs.
TetraMic Sound Samples
You can find a variety of recordings made with TetraMic at
www.soundofspace.com (thanks to Etienne Deleflie). Charles Veasey (user
name: cveasey), Paul Hodges (pwhodges), John Leonard (soundmanjohn),
Hugh Pyle (hughpyle), and I (LenM) have posted recordings made with
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.
Both VST plug-ins work with Nuendo 5, Cubase 3 (and possibly Cubase
4) and Reaper on the Mac. You can use the VVTetraVST plug-in to convert
TetraMic recordings to B-format, and then use any software that operates
on B-format, including our VVMicVST plug-in.
For use with ProTools HD, folks are using the VVTetraVST plug-in to
convert TetraMic recordings to B-format, and then using SoundField's
Surround Zone software with ProTools HD to decode the B-format
Both VST plugins work fine for recording and playback with Plogue Bidule
running on PPC Macs. VVTetraVST and VVMicVST also run fine on Intel Macs.
If you're using Logic, Plogue Bidule runs as a Logic plug-in.
Load the two TetraMic VST plugins into Bidule and use Bidule as an AU
plug-in in Logic. Bidule allows for individual channel re-routing, which
is difficult in Logic.
Fons Adriaenson's TetraProc also works fine on Macs. It's a fine
tool for multi-channel recording and also provides excellent two-channel
Jack and Ardour also work fine under OSX
AMBDEC allows for full ambisonic playback.
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.