On 2014-08-30 13:19:35 +0000, Gary Eickmeier said:
All right, I am going to attempt to burst the dam of silence on RAHE by
telling about the new speakers that I have designed and had built by the
capable hands of Dan Neubecker in Indiana. He didn't debut it in the
InDIYana event because the venue was not suitable for this type of speaker.
Brieflly, this is the embodiment of all of my Image Model Theory tenets on
how a speaker should be designed. I said that what we hear in a speaker is
its image model, which is the radiation pattern as reflected by the surfaces
nearby in a pattern of actual and virtual speakers, or sources. I want my
image model to look like a lattice of evenly spaced sources like this:
https://s3.amazonaws.com/masters.gal...81994e4099169d
To achieve this image model, the speaker needed to have more output in the
reflected direction, and a certain "shaped" frontal radiation, so we put two
gain pots on the two front panels to be able to reduce the frontal output
and at the same time do the distance/intensity trading effect called for by
Mark Davis in the Soundfield One speaker. We have settled on a -9 dB for the
outer front panels and - 3 dB for the inner panels. The speakers thus had to
have drivers on four sides of a square cross section box with MTM drivers on
each face, something like this:
https://s3.amazonaws.com/masters.gal...8ab783642bb6ef
and the final design looks like this:
https://s3.amazonaws.com/masters.gal...98e22052d64852
which, in my room, looks like:
https://s3.amazonaws.com/masters.gal...1be93b6797f2cc
I hope all of these images come through OK.
The room is 21 x 31 ft, the speakers positioned 5 ft out from the front
wall, 5 ft in from the side walls, for an image model that has all real and
virtual sources spaced evenly 10 ft apart.
The sound is as spacious as it gets, has very sharp imaging, speakers
disappearing entirely and casting a sound field behind, between, and to the
sides beyond the separation of the speakers in a way that makes it seem like
the musicians are right there with you. This is a sat/sub system with the
IMPs doing the satellite part and a Velodyne F-1800 doing the subwoofer
chores. It is balanced, full range, spacious, and precise.
I have yet to test them against other high end speakers, but I don't know
what else a speaker can do better in any of the audible areas of speaker
performance. Frequency response, radiation pattern, and room positioning,
that's all there is, there is no more.
Questions? Comments?
Gary Eickmeier
What sort of test setup did you use to measure the results of your
design? Do you have a favorite set of test mics? What sort of
measurement instruments do you use to confirm that your speakers match
the mathematical model of how they should perform?