The Ambiophonics volunteer team has made a lot of progress since the June
Surround Sound Conference in Banff. If any of you are coming to New York
AES I hope you will consider letting us give you a real demonstration of
what Ambiophonics is capable of, in a more home like setting, with new
Soundlab Ambiostat curved speakers and new software. There were several
things not optimum in Banff and some cockpit errors that we have since
corrected. None of them were theoretical and Ambiophonics really works.
Someday our own or other's implementations will match up to the theory 100%
but we are really getting very close now even just since June. I have two
home systems running, one with 28 speakers and the other a more affordable
one with 10 mini speakers. Both with video if you like. If you come I will
let you tweak things to your taste, just like you do with stereo.

Robin Miller is delivering an Ambiophonic paper on Sunday and we will be
around then and other days if you need transportation. The University of
Parma crew are also coming and have a paper to deliver. WAVES, the Israeli
professional audio company, has been measuring halls with Parma and they
will be at the Convention with a hall convolver product to announce soon.

We also finished the construction of the four channel Panorambiophone and
used it for the first time to record the Rutter Requiem during the 9/11
services near ground zero. The conductor says it is the most realistic
recording he has ever heard and he was gleefully pointing at his phantom
choir members and calling out their names and this was the two channel CD
rather than the four channel DVD/DTS version. We just needed one ten foot
stand first row center, no spots, no hall pickups, no booms, or worry about
the critical radius, etc. We expect to do a Beethoven's 9th soon. About
the only way we can promote Ambiophonics as a replacement for stereophonics
and 5.1 in homes is to get enough audio aficionados to hear it, like it and
reach a critical and irresistible vocal mass. Right now if you are a do it
yourself PC maven, we can likely get you going Ambiophonically.

Please e-mail or give me a ring at 201-784-0614 if you come to New York now
or anytime.

Ralph Glasgal
www.ambiophonics.org

More technical details on progress since Banff.

The new Ambiophonic system I have here now is easily far superior to
anything we tried to demo in Banff using Genelecs. Soundlab, an
electrostatic loudspeaker company, has fabricated for us tall curved panels
(Ambiopoles) with 70 Hz and up response used with subwoofers that act as
line sources. These speakers have two stators so that from the same panel
both direct sound and the crosstalk cancellation signal can be launched.
The XTC signal can then be adjusted in level, delay, or frequency response
to get the best results. But it is the curvature and uniformity that is
most important. If you set the speakers so that the beginning of the curve
is flat and facing its near ear and the curve recedes out sideways, then as
you lean sideways parallel to the speaker the level stays about the same but
the delay increases. At the other ear the level stays the same (if you
don't go too far beyond the inner edge) since you are just picking up
another line but the delay similarly increases. To make a long story short,
Ambiophonics now has a sweet area in width large enough so that you could
fall off an easy chair leaning at its sweet edge and in-line there is plenty
of room to recline or put seats in a row and watch a DVD concert video
centered on the video screen Of course, if you are on a budget you can use
cheaper speakers and live with a smaller sweet area. Much work can be done
to test other speakers and adjust software, in this regard.

Even more interesting is that the deterioration to the far side of the sweet
area is very gradual, as in stereophonics, and there is no pressure at the
ears at any location. Also with new Analog Devices boards, or a PC we are
adapting, and software the cancellation extends from 250 Hz to over 6000 Hz
(the upper limit is hard for me to tell). We do need to research even
better crosstalk cancellation filters and I am sure over the years more will
and could be done with even a little volunteer, mfg,. or AES, IRT, VDT, ITU,
support.

The next thing we have done is to add a second similar Ambiopole to the far
rear of the listening seat. When playing two channel material the rear
crosstalk cancelled Ambiopole is fed the same signal as the front one with
about a three millisecond delay. The effect of this is to further enlarge
the sweet area, widen the front stage, and enhance its apparent depth. This
widening/depth effect was predicted since it eliminates (through deliberate
pinna confusion) the pinna direction finding error at the extreme sides due
to having direct sound speakers so frontal. That is, the high frequency
signals from the rear form a pinna pattern that reacts with the same high
frequency signals from the front to eliminate the frontal pinna bias and
allow the side producing ITDs and ILDs to be heard with greater realism.
The addtional early reflection from a deverse direction adds to the depth
cues provided by the other surrounds.

Ralph Glasgal
www.ambiophonics.org