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Old 12th May 2008, 09:24 PM   #111
gedlee is offline gedlee  United States
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Quote:
Originally posted by el`Ol


What I donīt like about these devices is that the spacial image collapses as soon as I turn my head.
Most claimed CD devices are not. My CDs when positioned correctly have the largest "sweat spot" that I have ever found. They are designed that way as I don't believe in "one listener" setups.
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Old 12th May 2008, 09:31 PM   #112
gedlee is offline gedlee  United States
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Quote:
Originally posted by graaf


Only a CD device of narrow directivity can do this?
well, I don’t know
please take a look at Beveridge brochure

any comment?

best,
graaf
I looked at the designs. Seems like an expensive approach that requires some very specific things to happen for the technology to be effective. It might work in some circumstances, but the "white paper" glosses over several key issues. And NO data is shown on the speakers performance itself. Thats a very suspiciuos omission.
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Old 13th May 2008, 08:19 AM   #113
Colin is offline Colin  United Kingdom
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Interesting stuff. This thread gets better - thanks for joining in, Earl. Always good to have someone who has researched and measured the issues take part.

The only system I've experienced which tries to do away with the sweet spot is Ted Jordan's small line array. It holds a remarkably stable image from left to right. The array does have the disadvantage that, when listening too close, HF drops as you stand with ears above the levle of the array. This would presumably be lessened if listening from a greater distance. His home system is designed to blend into the room as much as possible, so you are not aware of the speakers visually or as sources for the music.

Earl - I read somewhere that you prefer surround to conventional two-channel stereo. Presumbly integration problems are compounded with four or more speakers?
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Old 13th May 2008, 09:22 AM   #114
graaf is offline graaf  Poland
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Quote:
Originally posted by Colin

The only system I've experienced which tries to do away with the sweet spot is Ted Jordan's small line array. It holds a remarkably stable image from left to right. The array does have the disadvantage that, when listening too close, HF drops as you stand with ears above the levle of the array. This would presumably be lessened if listening from a greater distance. His home system is designed to blend into the room as much as possible, so you are not aware of the speakers visually or as sources for the music.
a system that "is designed to blend into the room as much as possible" - EXACTLY! this is what is needed

Jordan recommends positioning of the loudspeakers as close to room walls as possible:
Quote:
It is also strongly recommended (again, against all convention) that loudspeakers be placed as close to a wall as possible.
The simple reason for this is that wall reflections will create two further 'virtual' loudspeakers that will create severe interference and impair spatiality. (The ideal, if impractical solution is to mount the drivers in the wall).
see: http://www.tnt-audio.com/intervis/jordan_e.html

BTW does anybody know Jordan's textbook "Loudspeakers" Focal Press 1962, which allegedly "has never been equalled for it's full mathematical analysis of loudspeaker theory and first principle derivation of all loudspeaker parameters, (now often referred to as the 'TS' parameters)"?

best,
graaf
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Old 13th May 2008, 09:57 AM   #115
Colin is offline Colin  United Kingdom
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Yes, I have a copy of the book. It is excellent. When I first read it, I was surprised at how little new stuff had come along since it was written (at least in terms of basic enclosures). There is some material about loudspeakers and rooms in the book but obviously it was before the availability of computer aided measuring hardware.

Ted is trying to get the book back into print. If no publisher picks up on it, we may have to try marketing it as a PDF download. Keep an eye on his website for details.
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Old 13th May 2008, 12:27 PM   #116
gedlee is offline gedlee  United States
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Quote:
Originally posted by Colin
Earl - I read somewhere that you prefer surround to conventional two-channel stereo. Presumbly integration problems are compounded with four or more speakers?
Thats not really correct. I prefer a three channel system to two, the center adds a lot, but I can do without the other suround channels. What you were probably refering to is my preference for DVD audio because its sound quality is often better. I think that this has more to do with the standardization of film audio mixing over CDs (which have no standard). CD quality has no controls of any kind, film does.

Quote:
Originally posted by graaf

"has never been equalled for it's full mathematical analysis of loudspeaker theory and first principle derivation of all loudspeaker parameters, (now often referred to as the 'TS' parameters)"?
Have you read my book?
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Old 13th May 2008, 12:36 PM   #117
Colin is offline Colin  United Kingdom
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Aha - you have two books on your site. GM pointed me in their direction a while ago. Which do you recommend for a general grounding in the sort of subjects we're tackling in this thread?

BTW, interesting about three channel. Again, this is something Ted wrote about in the 70s, advocating its use to make a more stable centre image. He used two fullrange drivers L and R, crossing in front of the listener, and a third in the centre, pointing up (the orientation was purely to roll off HF). Not quite what we think of as surround these days but interesting nontheless.
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Old 13th May 2008, 12:45 PM   #118
gedlee is offline gedlee  United States
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Quote:
Originally posted by Colin
Aha - you have two books on your site. GM pointed me in their direction a while ago. Which do you recommend for a general grounding in the sort of subjects we're tackling in this thread?

BTW, interesting about three channel. Again, this is something Ted wrote about in the 70s, advocating its use to make a more stable centre image. He used two fullrange drivers L and R, crossing in front of the listener, and a third in the centre, pointing up (the orientation was purely to roll off HF). Not quite what we think of as surround these days but interesting nontheless.

Transducers book is very technical - graduate engineering level (thats why I questioned the statement above). Its the better of the two books, but it is very high level. The other book is much lower level and in fact I am rewritting it and posting the rewrites for free.

I too advocate crossing the speakers in front of the listener as this has many advantages. BUT in order to do this you must have very well controlled directivity patterns because the listener can easily be 45° off axis. Not many speakers are flat 45° off axis.
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Old 13th May 2008, 02:10 PM   #119
Colin is offline Colin  United Kingdom
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Thanks for that. I'll have a look at the second title. Do you intend republishing as a dead tree edition when the updates are complete?

Ted's drivers are all about controlled directivity, although he goes for a 30 degree pattern. The speakers are then toed in to cross well in front of the listener. This works best with his 4 inch driver (rather than a single 2"), I presume because directivity extends lower. He uses the 4-unit array to achieve a similar effect with his smaller units. (Actually the larger driver has a response designed to mimic the array, rather than the other way round.)

BTW, this is my non-technical interpretation. There is a better description on his site here and here.
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Old 13th May 2008, 02:19 PM   #120
gedlee is offline gedlee  United States
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Quote:
Originally posted by Colin
Thanks for that. I'll have a look at the second title. Do you intend republishing as a dead tree edition when the updates are complete?

Ted's drivers are all about controlled directivity, although he goes for a 30 degree pattern. The speakers are then toed in to cross well in front of the listener. This works best with his 4 inch driver (rather than a single 2"), I presume because directivity extends lower. He uses the 4-unit array to achieve a similar effect with his smaller units. (Actually the larger driver has a response designed to mimic the array, rather than the other way round.)

I have no concrete plans for future books.

The sites that you list have no real data only verbiage, and I don't pay much attention to verbiage in audio anymore. Talk is cheap.

There is no way to create CD with piston sources - it is impossible. And if someone claims CD then I expect to see polars proving that because virtually ever time I hear this term used its not true.

I don't trust any statements in audio these days that are not supported with facts or measurements. I post all of the data for my systems. When I say they are CD I prove it.
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