[Andrew Haley]

Gary Eickmeier wrote:
Andrew Haley wrote:
Okay, I'll bite. I don't doubt that this arrangement would present a
huge soundstage. However, that first diagram, which shows laser-like
sound coming from the rear of the speakers is rather fanciful. In
reality, there will be a dispersal pattern which varies with frequency
and there won't be so much clean reflected virtual speakers as you
illustrate.

No, it doesn't show laser like sound coming from the rear. That is
just the ray tracing technique for showing the path of reflected
sound. If you take a look at the desired radiation pattern at the
lower left, you can see how I wanted the mid to high frequencies to
launch from the speaker in order to achieve the image model above.
Low freqs are always omni. But the IMP satellites have nothing below
100 Hz. Not sure exactly what range it starts to take on the desired
radpat, but all you can do is aim the four panels as shown and
adjust their gains and see if the model takes shape or not.

What frequency is that radiation pattern? It'd be interesting to know
how the pattern of those speakers varies with frequency.

The precedence effect predicts that these reflections will give the
impression of spaciousness but the second image won't be distinctly
separate as long as the walls are broadband reflectors: i.e. the
reflected sound has a similar spectrum to that of the direct sound.
So, nothing surprising there.

The caution with reflecting type speakers is that the speakers MUST
be positioned very precisely or else they will lose focus. If those
reflected (virtual image) speakers are not evenly spaced you will
get stretched soloists and no center imaging. If any one of the
elements of the model is missing, radiation pattern, speaker
positioning, and room acoustics, you could miss these qualities and
never discover all of the factors of stereo imaging. I stumbled upon
it by accident, then pursued the idea until I finally figured it all
out and had these built to do the concept on purpose rather than by
accident! The whole room was designed around the theory about 25
years ago, and now I am finally there!

What does this theory predict that conventional psychoacoustics does
not? In other words, is it possible to design an experiment which
would show whether the IMP is a superior theory to others?

Andrew.