The VMPS Patent, Parts I, II, III, IV

dwk · « **Reply #80 on:** 19 Oct 2005, 06:32 pm »

Very interesting - I had started thinking that your approach *wasn't* a waveguide but rather a geometrical rework of the driver, which left me skeptical.

I've played with some Monsoon planars in a waveguide, and my impression was extremely positive. Of course, with a wider throat the CD properties broke down in the treble, but IMHO retaining it into the upper mids gets you most of the way there. I am personally growing to believe that CD is absolutely a critical design element to making speakers work in real-world rooms. (either that, or listen nearfield, which is what I'm currently doing until I can get my waveguides finished)

I guess we'll know more when we see the pics, but how large is the mouth? Waveguides ultimately behave as aperatures as frequency drops, and below that the goal becomes seamlessly blending into the power response of the midbass/woofer drivers.

ctviggen · « **Reply #81 on:** 19 Oct 2005, 06:40 pm »

Ok, John, get working on those picks. As Corbin says, let us know what the cost is.

Aether Audio · « **Reply #82 on:** 19 Oct 2005, 07:24 pm »

Hmm...the means by which one can VERY SIGNIFICANTLY improve the performance of a transducer... is to incorparate a properly designed waveguide. Interesting. This especially appears to be excellent news for previous VMPS owners.

Way to go Brian!

-Bob

John Casler · « **Reply #83 on:** 19 Oct 2005, 07:28 pm »

Quote from: ctviggen

Ok, John, get working on those picks. As Corbin says, let us know what the cost is.

Just waitning for UPS to arrive which is usually 1:30 ish

Hopefully I'll have them up soon after they arrive.

Brian is figuring "production" costs for the upgrade so we'll have purchase pricing soon.

We have decided to offer it free, for a limited time (not specified as of yet) to anyone who orders speakers from today until we figure a "cut-off" date.

As soon as I have "ALL" that information, I will post it, in a seperate post.

ScottMayo · « **Reply #84 on:** 19 Oct 2005, 08:35 pm »

Quote from: John Casler

Brian is figuring "production" costs for the upgrade so we'll have purchase pricing soon.

Pricing, yes please. I have a bunch of drivers on my RM/X that are asking for this upgrade.

warnerwh · « **Reply #85 on:** 19 Oct 2005, 08:41 pm »

How long til regular production? I need them by Saturday

Florian · « **Reply #86 on:** 19 Oct 2005, 09:37 pm »

Where is the next show where you will show them? Mabye Dubravko is getting a set that i can listen too.

-Flo

koteng · « **Reply #87 on:** 19 Oct 2005, 09:38 pm »

If anyone who knows me reads this...

This would make a great christmas present.

Brian do you think it will be possible to get this mod in place by that time if I order it now?

Roger

Doublej · « **Reply #88 on:** 19 Oct 2005, 09:39 pm »

Implementation details aside, isn't this what Roy Allison did in the 1960s?

ctviggen · « **Reply #89 on:** 19 Oct 2005, 09:53 pm »

Roy Allison's designs do not appear to be waveguides:

United States Patent    4,029,910
Allison    June 14, 1977
Wide dispersion loudspeaker with flexing diaphragm

Abstract

An audio loudspeaker comprising a diaphragm which is rotationally symmetrical about an axis, the diaphragm including a sound propagating surface extending between a larger circular edge and a smaller circular edge spaced apart therefrom along the axis in the direction of sound propagation. The voice coil former is secured to the diaphragm adjacent the smaller edge, the larger circular edge is fixed relative to the magnetic structure (e.g., to the mounting panel) and the included, initially acute, angle between a tangent to the sound propagating surface and the axis increases as the point of tangency moves from the smaller edge to the larger edge.

United States Patent    3,983,333
Allison    September 28, 1976
Loud speaker system

Abstract

A room audio speaker system for use in combination with at least one room boundary surface, the speaker comprising an enclosure having a closed end wall for placement closely adjacent the room boundary surface and a second wall extending away from the end wall and providing a front edge and a rear edge, the latter forming a boundary with the end wall. Direct radiator audio reproducer means are provided generally flush mounted generally parallel to a portion of the exposed surface of the second wall. The included angle between the end wall and that second wall portion is no more than about 90.degree.. The distance along the second wall from the center of the reproducer means to the rear boundary edge is not more than one-half the smallest outside dimension of the second wall and the closed end wall is free from any audio reproducer means.

Brian Cheney · « **Reply #90 on:** 19 Oct 2005, 10:16 pm »

There is nothing in the prior art which does what this invention does, or employs a slotted waveguide to achieve Constant Directivity.

Good directivity or wide directivity are marketing terms. As Jon Risch pointed out, Constant Directivity has a meaning and the other terms like "controlled directivity" mean whatever one wants them to mean.

Cosmetically, the closest approximation to my patent is the Beveridge model 2SW of 30 years ago. It employs a slot-like "acoustic lens" approx 8" to 9" wide to vent a cylindrical enclosure, in the center of which was mounted a full-range electrostatic diaphragm. There was a large open cavity in front of the diaphragm, and a sealed one behind it. Considerable acoustic energy reflected back into the diaphragm, more when the system was played at louder levels. This caused a limitation on maximum SPL which peaked at around 90dB SPL/1m. The "acoustic lens" was far too wide to provide good directivity above about 1500Hz, and this disparity between good directivity below 1500Hz and beaminess above led to the imaging anomalies Harry Pearson noted in his "anniversary" TAS review of the 2SW. In addition to being the same width as the wavelength as the highest frequency for which CD response was desired (2/3" and 20kHz in my design), our waveguide touches the front baffle and is sealed against the panel stators with absorptive countermeasures to prevent any considerable amount of energy being bounced back into the diaphragm.

Do a search on "Beveridge loudspeakers" for more details.

John Casler · « **Reply #91 on:** 19 Oct 2005, 10:23 pm »

OK B,

I am loading the Pics. feel free to enter this post and add your descriptions of captions, and erase my wording

Here is the RM30 wave guide:

John Casler · « **Reply #92 on:** 19 Oct 2005, 10:25 pm »

RM30 with Prototype CD Wave Guide in place

John Casler · « **Reply #93 on:** 19 Oct 2005, 10:27 pm »

RM40 Prototype CD Wave Guide

John Casler · « **Reply #94 on:** 19 Oct 2005, 10:30 pm »

RM40 and RM1A with Prototype CD WaveGuide in place

Brian Cheney · « **Reply #95 on:** 19 Oct 2005, 10:32 pm »

The smaller speaker in the lower photo is actually the new RM 1a ($1780pr).

John Casler · « **Reply #96 on:** 19 Oct 2005, 10:44 pm »

Quote from: Brian Cheney

The smaller speaker in the lower photo is actually the new RM 1a ($1780pr).

B,

Went back and corrected that

I should have looked closer.

Everyone of course needs to know that these are "PROTOTYPES" and that is why the look so rough.

klh · « **Reply #97 on:** 19 Oct 2005, 10:53 pm »

Am I a moron, or are you going to do more than put a baffle in front of your loudspeakers?

JoshK · « **Reply #98 on:** 19 Oct 2005, 10:55 pm »

Is the angle close to 90º? Looks like a VERY shallow waveguide, but what do I know.

Brian Cheney · « **Reply #99 on:** 19 Oct 2005, 10:58 pm »

I hope I can head off a lot of FAQ type enquires by telling you the following:

"Sawtooth" Chris Regan, my patent attorney, has advised me to release no more technical details about the invention until the patent is granted in about 18 months.

Since the invention meets the Novelty criterium the Patent Office places first and foremost, there is little doubt it will be granted in time.