The Advantages of Floor Coupled Up-Firing Speakers

I have recently found an interesting paper by P.W. Klipsch summarizing His extensive tests:
Stereo Geometry Tests

excerpt:
Previous experiments by the writer have shown that the stereo effect becomes marginal at a distance about 1.5 times the spacing of the flanking speakers, which is the prime purpose for wide speaker spacing.

Klipsch argued for angles larger than typical audiophile equilateral triangle of today because "stereo in the sense of reproducing the original spatial relationships requires larger angles. Large angles are best served with flanking speakers spaced to the corners, even to the extent of using the long wall of an oblong room"

interestingly, larger angles is also what one gets with Beveridge placement, Beveridge was able to propose His own different kind of stereo geometry, taking the speakers out of the corners because of narrow line source characteristics of His speakers
in contrast Klipsch was working with highly directive speakers - therefore to achieve the same level of homogeneity He had to put the speakers in the corners with significant toe-in (He advocated around of 45 degrees of toe-in)
 
I have recently found an interesting paper by P.W. Klipsch summarizing His extensive tests:
Stereo Geometry Tests

excerpt:


Klipsch argued for angles larger than typical audiophile equilateral triangle of today because "stereo in the sense of reproducing the original spatial relationships requires larger angles. Large angles are best served with flanking speakers spaced to the corners, even to the extent of using the long wall of an oblong room"

interestingly, larger angles is also what one gets with Beveridge placement, Beveridge was able to propose His own different kind of stereo geometry, taking the speakers out of the corners because of narrow line source characteristics of His speakers
in contrast Klipsch was working with highly directive speakers - therefore to achieve the same level of homogeneity He had to put the speakers in the corners with significant toe-in (He advocated around of 45 degrees of toe-in)


Isn't it true that Blumlein, the inventor of stereo, suggested +-45 degrees stereo triangle ? Just see Blumlein's stereo microphone with crossed dipoles !

In practise, however, psychoacoustics strikes back, and a hole in the middle can be perceived with too wide base angle. Probably for this reason usually narrower angle is used.

I don't know where +-30 degrees comes from ? Maybe equilateral just looks nice ? :D


- Elias
 
Klipsch and also Jordan advocate for even wider angles than 45 degrees

ps.

as to Jordan's linear array system He recommended that the stereo base could be as much as 15 feet wide with very flat loudspeakers wall mounted and toed in 60 degrees so their axis cross well in front of the listener area
 

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I think the hole in the middle is just the typical loss of the center image when path lengths aren't exact. There is also the question of how much well centered material the recording contains. Classical music with spaced mics might be weak in this area. There are a lot of early pop stereo recordings that use left center and right as the only image locations. They would make a good test (I'm listening to a "Best of Marvin Gaye" these days, which would suit.)

Klipsch was mostly following the recommendations from the Bell Labs experiments that he liked well enough to reprint and distribute. If you must put your speakers in opposite corners then adding a center can be helpful. Note that for a period of time he was advocating a center channel connection that used out-of-phase difference information, until that error was pointed out to him. Even the greats make mistakes.

David S.
 
from an article by Alvin Foster:


Harmonic and IM distortion, phase response/time lag, transient response, squarewave reproduction, decay time, etc., measured in my tests and others', have proven to be unreliable indicators of a loudspeaker's playback quality. I cited, among others, the definitive research of Salmi and Wickstrom, Toole, and at Bose, all of which concluded that such distortions pale in significance to frequency response and dispersion pattern.
 
Test your center image with mono recordings. Simple. I happen to like the sound of 2 channel phantom mono better than single speaker, FWIW.

Me too. The phantom source from the Linkwitz Pluto 2.1's is far more believable than any box sitting between the speakers. Actually it is the best phantom centre I have ever heard, from many, many speakers. This and pin sharp imaging.

Centre speakers are essential if you have listeners sitting way off axis. Certainly they are less problematic in larger rooms where they are less identifiable as a seperate source.

I never hear twin mono with Pluto 2.1, just rock solid central image.
I have heard twin mono effects with other speakers, sometimes frequency dependent.
Also I always have to check if the TV sound is still on when I watch a movie with the Pluto's.
 
I guess this is a correct thread to disscuss about flooder, without the fear of moderator's thread split :rolleyes:

This week I had good experience with other type of a flooder ! In the office I have small table top speakers and neccessarely they are placed relatively close less than 1 m. Initially they were placed in conventional way facing the listener and lifted at the ear level. The table is placed against a wall corner. The sound is very sensitive of listener placement which in on office environment cannot be guaranteed to be optimal most of the time. The stereo interference field kills the enjoyment totally.

Then I flooded the speakers by turning them facing ceiling, and after adjusting treble level by tone control to compensate the off axis there was an immediate improvement of the stereo sensation. They are still placed at the ear level, and less than 1 m distance. The spaciousness increased dramatically, no longer the sound comes from the small boxes but appears coming far away behind the front wall. Nice ! :)

- Elias
 
I guess this is a correct thread to disscuss about flooder, without the fear of moderator's thread split :rolleyes:

This week I had good experience with other type of a flooder ! In the office I have small table top speakers and neccessarely they are placed relatively close less than 1 m. Initially they were placed in conventional way facing the listener and lifted at the ear level. The table is placed against a wall corner. The sound is very sensitive of listener placement which in on office environment cannot be guaranteed to be optimal most of the time. The stereo interference field kills the enjoyment totally.

Then I flooded the speakers by turning them facing ceiling, and after adjusting treble level by tone control to compensate the off axis there was an immediate improvement of the stereo sensation. They are still placed at the ear level, and less than 1 m distance. The spaciousness increased dramatically, no longer the sound comes from the small boxes but appears coming far away behind the front wall. Nice ! :)

- Elias
Place them now speakers towards wall. so the wall becomes the radiating area.
 
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Layered Sound

So far I have not found references to Shelley Katz on this site. Please look at Discover the hidden layers of music with Shelley Katz where he gives a presentation on the concept of "Layered Sound".
What he appears to be saying is that the focus on pinpoint accuracy of sound reproduction ignores the emotive requirements of sound reproduction. He makes the analogy of his Steinway live vs. reproduced via high quality speakers.
His solution is to combine traditional high quality speakers producing so-called coherent sound, together with his transverse wave panel speakers. These speakers (see Podium) are excited by a set of drivers so as to add the resonances (incoherent sounds) which are typical in a live environment but which are generally lost in the close-miking recording process.
This works providing we are prepared to abandon the attempt of recreating the ambience of the original location in preference to our own ambience, via the flat-panel speakers.
This is an interesting proposal and might account for the popularity of some older speakers which bring their resonances and "character" into play and which at the same time enhance the listening experience.
So, I really wanted to ask if anyone in this forum is following any of this development.
Personally I am all for abandoning the search for ultimate detailed reproduction (of sounds!) in favour for maximal involvement in the reproduction. This seems to be the direction in which Shelly Katz is going. I am also wondering whether his comments are not a critique of recording methods currently being used which lead to a lack of ambience?
George
 
Layered Sound

Hi,
I did not attend the presentations at TedX, but I did attend a presentation in Cambridge recently. It was very similar except that he went into a little more detail about the future of his loudspeakers.
He seemed to be saying that he had a revised design which would allow the speakers to be manufactured / available (a bit unclear as to what he really meant) at "Maplin prices". Now if he is talking DIY then I am interested in this approach as it really should not be that difficult... once the design has been done of course. And it does not involve any extra electronics, DSP or worse. It does seem to upset some people that we are adding to the "original" sound, but in the sense that the recorded sound is the original sound minus the ambiance, perhaps it could be seen as adding back a little of what we are owed. But, it will nit be the same as what was removed.

George