In this video shot at BVE 2017, Sennheiser's Customer Development & Application Engineer Andy Lillywhite takes Pro Tools Expert's Editor, Mike Thornton through a demo of their new Ambeo microphone as well as a demonstration of potential ambisonics workflows used to produce binaural audio for virtual reality content.
What is Ambisonics?
The Ambisonics format were way ahead of their time. The Soundfield mic was originally invented by Michael Gerzon and Peter Craven and their theoretical design was subsequently developed into a practical microphone system by Calrec Audio Limited, who launched the first Soundfield mic in 1978.
Ambisonics has been around for a long time and the most well known name in Ambisonics is The Soundfield. Many years ago I recorded a demo CD for AMS, then owners of the Soundfield brand. The final recording we made was a choir singing an African song whilst dancing around the mic. At that time (1991) there was only one place where you could play it back and experience the full Ambisonic experience with height and that was the demo room in the AMS factory in Burnley, not 20 minutes drive for me from Manchester.
It is only now with the introduction of immersive sound formats and with the introduction of virtual reality with binaural playback that the Ambisonics format has at last found a home and so I am looking forward to a resurgence of Ambisonics as a native format to record immersive sound in.
A Or B Format
A Format is essentially the output from each of the 4 microphones when they are arranged in a tetrahedral array. The 4 channels are often labelled LF (Left Front) RF ( Right Front), LB (Left Back) and RB (Right Back). This native A format is often converted into B Format labelled W, X, Y & Z as it becomes easier to manipulate the B Format to produce a wide range of mic layouts and the option to steer and zoom in post production. Sennheiser have produced their own free A to B format plugin to handle the A t B format conversion.
Once you have your ambisonics recording in B format there are a range of tools to take the B Format signal and convert it into a number of the immersive formats as well as binaural audio which is ideal for virtual reality playback devices.
In this video, Andy shows the Noisemakers Ambi Pan, ambisonics B format panner to enable you to pan single sources and position them in the ambisonics soundfield. Next there is the Noisemakers Ambi Head plugin plugin which renders out the b format audio into binaural audio and as Mike found out in this demo, there are a number of models that all produce very different results.