[mca]

A nice comment by Roger Gordon of Positive Feedback:

VMPS / Bruce Moore - VMPS was demoing their RM-30C loudspeakers with the new constant directivity waveguide. The waveguide replaces the usual grill cloth with a solid covering over the tweeter and the three ribbon midrange drivers. The covering has a slot cut down the middle that is 2/3rds of an inch wide. The slot serves as a diffraction grating that turns the midrange drivers and tweeter from point sources into line sources. Line sources radiate in a 180 degree dispersion pattern―hence the term constant directivity. The advantage of constant directivity is that there no longer is a sweet spot. The sound is essentially the same anywhere in front of the speakers. This is a big claim that I was most anxious to test seeing as I own a pair of RM30M loudspeakers. I tested the claim by moving around the room while playing a number of my CDs. The constant directivity waveguides worked as claimed. Until you went behind the plane formed by the front of the two loudspeakers the sound was essential the same regardless of your position. No more sweet spot. Amazing. The Bruce Moore tube electronics mated very well with the VMPS speakers. In fact, to my ears, this is the best the VMPS room has ever sounded and that includes the two years when they won Best of Show at CES in 2002 and 2003.

[John Casler]

More Feedback from AA members:

http://www.audioasylum.com/audio/speakers/messages/214241.html

[dubravko]

From http://www.stereotimes.com
 
"The third bang for the buck system I happened upon was in the VMPS/Bruce Moore suite, in ST1303. We heard the RM30C speakers ($3700), which use VMPS’s new, patent-pending Constant Directivity Wave Guide technology. The wave guide appears to be a thick acrylic plate with heavy damping material on the back, which covers the midrange ribbons except for a 0.667-inch aperture that runs down the center of the midrange driver array. This technique is responsible for allowing 180-degree high frequency dispersion, resulting in a very even frequency balance along the lateral plane. It greatly improves off-center, out of the sweet spot listening, to which I can attest. Bruce Moore 225-watt mono tube amplifiers ($15k) were employed to drive the RM30C’s, and two VMPS Original subwoofers ($499 ea.) filled in the bottom octave bass. The sound was dynamic, natural, and clean; and was comparable to the price-no-object systems at the show."

[John Casler]

From http://www.stereotimes.com
 
The sound was dynamic, natural, and clean; and was comparable to the price-no-object systems at the show."...

I think I heard that comment more often during this show than ever before.