(Last updated 04/03/2020)
Recording With OctoMic
OctoMic has an unusually extended low frequency response. If we
wanted to go a bit overboard, we could calibrate it to be flat to well
below 20 Hz and you could use it as an earthquake detector! But we
reasonably limit its response so that it's usable down to around 25
As with any high quality microphone that works well down to those very
low frequencies, you must use a shock mount unless you really want to
pick up footsteps, trucks rumbling by, distant thunder and subway
trains. So please always use an effective shock mount. (See the OctoMic
Accessories page for recommendations.)
OctoMic's output is a 12-pin jack. A 12-pin PPAc8 cable connects it
to the PPAc8 transmitter. Since OctoMic's signal is unbalanced at that
point and somewhat susceptible to picking up strong electrical
interference, we recommend keeping that PPAc8 cable length as short as
possible and routing it away from high power sources of interference.
The PPAc8 transmitter connects to two shielded EtherCon cables, each
of which carries four channels. The EtherCon cables can run for more
than 500 feet without degrading the audio signal.
The two EtherCon cables connect to two PPAc8 receivers. Each receiver
has four XLR plug outputs, for a total of eight.
OctoMic's PPAc8 system can feed the signal to either an eight-channel
recorder that has its own mic pre-amps, or an eight-channel microphone
pre-amplifier/ADC (analog-to-digital converter) that feeds an
eight-channel digital audio recorder. The recorder can be either a
computer or a stand-alone digital audio recorder.
F8 and F8n
eight-channel portable digital audio recorder are probably the
most cost-effective and simplest ways to record with OctoMic. The
combination makes very high quality 2nd-order ambisonic recordings.
You can buy a Zoom F8 or F8n in the US for $1000 or less.
An alternative to the Zoom F8n is the Sound
Devices MixPre-10 II.
Other possible alternatives are the Sound Devices 788T, Roland R-88
and the SonoSax SX-R4+/SX-AD8+ combination.
Connect OctoMic to the recorders using OctoMic's PPAc8 system. The
PPAc8's two receivers terminate in eight XLR connectors. Plug them
directly into the recorders' eight XLR inputs.
Both the Zoom F8n and the Sound Devices MixPre-10 II have very accurate,
digitally-set level controls so it's very easy to match the levels
across OctoMic's eight channels. Both recorders can gang the eight
channels' level controls, so you can control the levels with one knob.
Both recorders are recommended!
To preserve OctoMic's calibrated performance, all eight OctoMic
channels should be gain-matched to within 0.1 dB. Please use mic
pre-amps and A-to-D converters that are designed to hold those gain
tolerances across eight channels.
OctoMic's raw eight-channel audio output are in what's called
"A-format". When you transfer them into your digital audio workstation
for editing, convert them to standard 9-channel 2nd-order B-format with
the supplied VVOctoEncoder VST encoder plugin.
The following DAWs can be used for editing 2nd-order B-format:
- Pro Tools HD
- Cubase (pending)
- Nuendo (pending)
- Pyramix (v11.1 and higher)
- Digital Performer
- Plogue Bidule
- FLStudio (with proper mixer and plugin I/O configuration)
If your PC runs Linux, you can use Fons Adriaenson's OctoProc
OctoMic's 9-channel B-format has been confirmed to work well with
the Facebook 360 Spatial Workstation.
VVOctoEncode is the A-to-B-Format encoder VST/AAX plugin supplied with
OctoMic. It was developed and is supported by David McGriffy
Once you have your coupon code from us, you can download VVOctoEncode here.
VVOctoEncode allows you to select among three options during encoding.
The first option has the least processing noise and provides excellent spatial
The second option adds a slight amount of processing noise but has slightly
stronger spatial location cues.
The third option adds a bit more processing noise but has even slightly stronger
spatial location cues.
We advise that when encoding very quiet sound sources, that Option 1 be the
default selection. When the sound sources are louder, we advise considering
using Options 2 or 3.
We have great news for OctoMic users who work in Linux environments!
Fons Adriaensen has released the source code for Octofile version 0.3.0.
Octofile is an A- to B-format encoder for Octomic.
OctoMic is the world's finest Blumlein array. See the X and Y B-format
channel polar patterns to confirm this.
To use OctoMic as a Blumlein array:
If you use a block and wire application like Plogue Bidule for your
plug-ins, here's what the layout looks like:
It takes second-order B-format as input, and both plays and records Blumlein.
Some recording engineers prefer recording with spaced arrays of microphones to
coincident arrays. Recordings made with spaced arrays offer a sense of spaciousness due
their spatially decorrelated ambiences.
The simplest spaced array is probably the ORTF array. Two first-order
cardioid microphones are spaced 17cm apart and aimed at +/- 55 degrees
(110 degrees between them).
Two OctoMics make a superlative ORTF array. That's because their
decoded first-order cardioid directivity patterns are almost perfect up to
around 10 kHz. (See OctoMic's polar directivity patterns here.)
And since the first-order cardioid mic decodes used in this ORTF
array are decoded in post-production, the aiming of the two cardioids
can be easily fine-tuned back in the studio.
This same approach can be taken with larger and more complex spaced
arrays, including ESMA, ESMA-3D, ORTF Surround and ORTF-3D, Hamasaki Square and Cube,
Decca Tree and many others. They all benefit from OctoMic's very precise
and stable first-order decodes.
There's another benefit to using OctoMics in spaced arrays: lower
cost. For example, in an ORTF-3D array, there are two first-order
supercardioid microphones at each corner of the array. If you were
using mono mics, you'd need two physical microphones at each corner, for
a total of eight mono microphones. In contrast, you can populate that
array with only four OctoMics. Each OctoMic gets decoded to two
For a nice surprise, compare the cost of the eight high-end mono microphones
in an ORTF-3D array to the cost of four OctoMics!
ORTF Array With Two OctoMics
ORTF-3D Array With Four OctoMics
Here's how we did the ORTF decode using Plogue Bidule:
We recorded A-format (raw capsule audio from the two OctoMics) to a
sixteen track recorder. Tracks 1 through 8 were from the left
OctoMic. Tracks 9 through 16 were from the right OctoMic. Each OctoMic's
A-format were encoded to B-format using one VVOctoEncode plugin (supplied with each
OctoMic) using its own specific calibration files. The B-format outputs
went to two instances of SPARTA Beamformer. Both were set to decode to
first-order cardioid. The left Beamformer was rotated to -55 degrees, and
the right to +55 degrees. The outputs of the two Beamformers went to a
gain control and then to a player and file recorder.