New Audio Formats: A Time of Change, and a Time
of Opportunity. This was a "White Paper" I wrote while at Sonic
Solutions. I suppose it is really their property. It was written early in the
development of hi-res audio of various kinds. This was an attempt to describe
these developments, which were new and unknown at the time, to audio professionals
with varying degrees of technical expertise.
Joys of Conformal Mapping: Applications to Digital Filtering in the
Studio - 2nd Try. This is an expanded version of two
papers. One appeared in the Journal of the Audio Engineering Society, Volume 31, Number 11, November 1983,
pp826-841. The other ("General Spectral Transformations for Digital
Filters") appeared in the IEEE Transactions on Acoustics, Speech and Signal
Processing, Volume ASSP-29, Number 5, October, 1981, pp1092-1094. There is a fair
amount of new material added, especially on notch filter design. A number
of gratuitous editorial comments have been redacted.
Rational Basis for Multichannel Music Recording. (with Jack H. Vad) Circa 1999. This is an expanded version of the paper
that was presented at the 104th AES Convention (May 1998). It is quite a bit more
complete and contains more extensive discussion of rematrixing and
after-the-fact repositioning. It is significant because it points out that if
the original multi-track mix is produced using this methodology, it can automatically
generate a stereo mix for CD mastering. Furthermore, if you sell or download the
3rd channel, you can combine that 3rd channel with the data on the CD to produce
the original surround mix. And, as always, this can be matrixed into any number of
speakers in any orientation.
Extension of the Method
of Spatial Harmonics to Three Dimensions. All the stuff I did using spatial harmonics
was published in 2-dimensions. This just shows the math all in 3 dimensions for completeness.
Also, I switched notation from Gerzon's direction-cosine form to the more traditional
Legendre function form. This makes it easier to use classical theory to figure out
what is going on. It also makes it easy to use routines from, for instance, Numerical
Recipies to calculate the speaker gains.
Microphones: Part 4. With boundless hubris, I have dared to name this paper
as part four, following 3 articles by Michael Gerzon from the 1970's. This extends his
theory to multiple microphone arrays with arbitrary directionality and flat frequency
response. This is the wierdest paper I have ever written, in that it describes
an invention that may not ever be built in my lifetime.