AES and 5.1 Surround all in one Mics

Today I attended a seminar on single device surround mics, six different manufactures where there to talk about their own designs and how they work.

They were:
Gary Elko from mh Acoustics LLC with their Eigenmic which uses 32 elements arranged in a sphere and by using their software many types of pickup patterns are possible as well as steering the direction of the sound pickup so that afterwards you could pickup and focus on any sound in a 360 degree pattern around the mic. It was very impressive, and talk about fixing it in post.

Morten Støve from DPA Microphones showed their DPA5100 surround microphone, it looks like a bicycle seat thats been over inflated. Its meant to be mounted on top of your camcorder and has screw attachments on the top and bottom. Its output is six discrete analog lines to get the 5.1 audio in real time, no processing required. To use it you would need an outboard audio recorder but it’s simple and compact. Morten showed slides of how they prototyped it using cardboard and mics taped on.

JIm Pace from Sanken Microphones / plus 24 showed and talked about their WMS-5 self contained five channel microphone, the first encapsulated within a single body. He showed how, with only three mics, that they could reconstruct a five channel surround image, they used new rectangular electric condenser microphones that allow for their exact placement on the body of the main unit.

Helmut Wittek from SCHOPES Mikrofone GmbH showed off their surround mic system, it produces a discrete 4.0 audio from four mics arranged on a elongated X frame. Its main use for picking up ambient surround sound. They also have surround mics that used only three pickups arranged in various ways but they need a computer plugin or an external box to convert to 5.1 surround and they work very well.

David Josephson from Josephson Engineering talked about his own 5.1 surround single unit microphone C700s that again uses three pickups to derive a surround recording. What he and others are using is call a B-Format or Ambisonics which is a mathematical system for recording a complete surround pattern using just a few microphones. This makes the actual mic much smaller and easier to use. But they do require decoders to retrieve the discrete channels.

Pieter Schillebeeckx of SoundField and he talked about their DSF-2 which again uses the B format to create a complete surround sound field with just four mics. Pieter’s demonstration included using SoundField’s software to playback a music piece and then steer the audio so that is sounded like you were moving the microphones around the room during the recording. It was amazing.

There was some talk about a soon to be released AES standard on a six channel connector for plugging in these multichannel microphones that Mr. Joesphson was working on.

And the topic of today’s workflow came up in that, many of today’s camcorders only have four tracks to record and two are reserved for talent mics which leaves only two for surround sound pickup. Without using an encode/decode system there is no practical way to get anything other than a stereo recording. And that is what was suggested, make a good quality wide stereo recording and if a surround is needed use the wide stereo to feed a Stereo to 5.1 converter.