Speaker with a "linear wavefront in the horizontal plane" ?

[chaywood]

I was reading a loudspeaker patent and it mentioned a "linear wavefront in the horizontal plane". What kind of driver layout would that be ?

Thanks !

Charlie

[Bill Fitzmaurice]

I'd have to see the abstract to venture an opinion. There's lots of bullpucky to be found in patents. Often it describes something that is commonplace.

[chaywood]

A Graham Holliman Loudspeaker Brochure can be seen in this ad:
http://imageshack.com/i/go6lwcj

He also has a patent for a bass unit and the patent below describes the "improved" mid and high unit.
Check out the specs on the brochure.... 4hz to 40khz +- 2 1/2db on the pro unit and 8hz to 22khz flat on the domestic units....

Description of GB2211049 (A)
Graham Holliman, Inventor

A LOUDSPEAKER FOR
GREATER REALISM AND STABILITY
OF THE
ACOUSTIC IMAGE.

This invention relates to a loudspeaker system for single channel or multi channel sound
production and reproduction, for use in domestic Hi-Fi systems, recording studios and other
professional installations.
Loudspeakers and their uses in such single and multi channel systems are well known.
Normal loudspeakers however suffer from an inability to accurately portray the illusion of
reality; that is, one is invariably aware that one is listening to a loudspeaker system and not
the real thing, irrespective of how complicated or expensive such loudspeakers may be.
One factor which is of particular importance in creating an acoustic illusion of reality is
described below.
The vast majority of real sounds emanate from a source which lies at a distance from the
listener which is much greater than the distance of the loudspeaker system which is used to
create the illusion of real sounds.
When a listener moves with a'real' sound field, the perceived directional information
concerning the locations of an original sound source and the acoustics within which that
source is located vary very little with considerable listener movement. This is not the case
with the reproduced equivalent, where, due to the close proximity of the loudspeakers,
directional information varies wildly with even small movements of the listener.
This means that the sound stage reproduced by loudspeakers of conventional types is
fundamentally unstable, and cannot reproduce the elusive quality we call realism.
If each loudspeaker of a sound system is designed to provide a wide, coherent source of
sound, radiating an approximately linear wavefront in the horizontal plane ( or, in special
cases, a wavefront with carefully contrived deviation from basic linearity, which may or may
not be user controllable, in said horizontal plane ) the aforementioned criterion of small
angular displacement of acoustic information with listener- movement can be satisfied, with
the attendant increase in realism.
It must be pointed out that the wavefront need not be linear, or even near linear in the vertical
plane, but may be so if desired. It must also be pointed out that, the wider each coherent
sound source is made, the wider will be the emanating wavefront, and the larger will be the
resulting horizontal area of acceptible realism within which the listener is free to move. The
listening environment will of course dictate in practice the limits of width which can be
tolerated! The designing of a good coherent source should be well within the capabilities of
any competent engineer, as the governing principles are well known.
It would of course be quite easy to assemble or design a system which, while employing the
above techniques, also incorporated some of the more established design principles; for
example, one can envisage a speaker using the technique herein described for say the
middle and/or the upper frequencies only, and employing conventional techniques to
produce the bass register.

CLAIMS

1. A loudspeaker system for single channel or multi (two or more) channel reproduction (or sound production), in which each loudspeaker channel approximates a wide, coherent source of sound, radiating an approximately linear wavefront in the horizontal plane.

2. A loudspeaker as in claim 1. where the approximation to linearity of the radiated wavefront in the horizontal plane is made to deviate from actual linearity in a carefully contrived way which may or not be user controllable 3. A loudspeaker substantially as herein described.

4. A loudspeaker as claimed in any other claim, which, in addition, also employs more established design principles for parts of its mode of operation.

[Bill Fitzmaurice]

I don't see anything there that actually explains what it supposedly does or how it does it.

[chaywood]

I don't see anything there that actually explains what it supposedly does or how it does it.

That's why I was confused... There are no drawings or other info in the patent....

Thanks !!!

Charlie

[Ryan A]

4 hz to 40k hz @ +-2.5db?

Guess we'll have to take their word for it since anything below 20hz is going to be hard to discern. If it can even produce 20hz I'd be happy.