Processing the Tracks

Choosing the target formats

People still generally want stereo CDs of recordings; sad but true.  By making a UHJ encoded file, we end up with a CD which is playable as stereo or, in principle, decoded to play in surround - but I suspect that less people can decode UHJ recordings than can play any other form of surround files.  None the less, UHJ encoding is a good way to produce the stereo files because it preserves the greatest amount of information from the three source channels.  Nearly all Nimbus recordings, and a few from some other manufacturers, are UHJ encoded.  Because this ends up as a standard CD, the sample rate is 44.1kHz.

For the full surround experience, realising that hardly anyone can play either .AMB files or UHJ encoded disks in full surround form, we resort to generating speaker feeds that can readily be played on the systems found in a large number of homes.  This was originally called D-format; but is now called G-format - a term originally coined specifically for a decoding  designed to use the speakers of a standard home theatre layout.  Like Nimbus on their DVDs, I have chosen to decode for a square layout, which is not far from the arrangement of the speakers of a typical home theatre setup (omitting the centre front speaker for improved symmetry).  I encode these speaker feeds using DTS at 44.1kHz for burning on a CD (it costs hugely more to buy the capability of encoding at 48kHz for burning on a DVD, so I don't).

For use on iPods or similar personal players, a binaural representation of the recording, using a generic HRTF, might be worth experimenting with.  However, I personally find the binaural effect very uncertain even with a true binaural recording, so I may not be the best person to try this out!

See the menu on the left for details of how I go about generating these formats.

Ambisonic Info header