loudspeaker stereo imaging
 

On Thu, 13 Nov 2003 18:02:37 +0000
Ian Bell wrote:


It has a lot to do with the positions of the HF and LF drivers and
your listening position. These result in errors which can muddy
the stereo sound field. The only real solution is to use dual
concentric speakers.

I'd be highly sceptical of that.

Put *any* set of speakers in your room, and play a (say) 8-10kHz
sine wave out of both speakers.

Then walk around the room and be enlightened.

That's because of room acoustics not the speakers. Given an
acoustically good room (a rarity indeed), what I said still stands.

I dont see how 'dual concentric' speakers are meant to help in any case
- they have a good number of design compromises (mistakes, even) all of
their own.

Can you clarify?

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with
ketchup.

loudspeaker stereo imaging
 

"Ian Molton" wrote in message

On Thu, 13 Nov 2003 18:02:37 +0000
Ian Bell wrote:


It has a lot to do with the positions of the HF and LF drivers and
your listening position. These result in errors which can muddy
the stereo sound field. The only real solution is to use dual
concentric speakers.

I'd be highly sceptical of that.

Put *any* set of speakers in your room, and play a (say) 8-10kHz
sine wave out of both speakers.

Then walk around the room and be enlightened.

That's because of room acoustics not the speakers. Given an
acoustically good room (a rarity indeed), what I said still stands.

I dont see how 'dual concentric' speakers are meant to help in any
case
- they have a good number of design compromises (mistakes, even) all
of their own.

Can you clarify?

I'm not aware of a lot of compromises and mistakes that are inherent in dual
concentric speakers. You might want to list some.

The advantage of dual concentric speakers is that it provides a woofer and a
tweeter that have acoustic centers that coincide. Every speaker can be
idealized as a sound source acting at a single point. With non-concentric
designs, the two sound sources are separated by an appreciable distance,
and this distance interacts with the crossover to produce lobing in the
range where the driver's output overlaps. With a dual concentric design, the
two sources can be made to be very close or to even coincide.

Speakers like the KEF Q15 are true dual concentric designs. The tweeter is
built at the base of the woofer cone. Tannoy is famous for dual concentric
designs patterned after older designs by Altec Lansing. They place a
horn-loaded driver at the base of the woofer's cone and are thus
dual-concentric.

Since they avoid lobing, dual concentric designs are more tolerant of
various speaker placement alternatives, and are favored for near-field
listening.

loudspeaker stereo imaging
 

"Ian Molton" wrote in message

On Thu, 13 Nov 2003 18:02:37 +0000
Ian Bell wrote:


It has a lot to do with the positions of the HF and LF drivers and
your listening position. These result in errors which can muddy
the stereo sound field. The only real solution is to use dual
concentric speakers.

I'd be highly sceptical of that.

Put *any* set of speakers in your room, and play a (say) 8-10kHz
sine wave out of both speakers.

Then walk around the room and be enlightened.

That's because of room acoustics not the speakers. Given an
acoustically good room (a rarity indeed), what I said still stands.

I dont see how 'dual concentric' speakers are meant to help in any
case
- they have a good number of design compromises (mistakes, even) all
of their own.

Can you clarify?

I'm not aware of a lot of compromises and mistakes that are inherent in dual
concentric speakers. You might want to list some.

The advantage of dual concentric speakers is that it provides a woofer and a
tweeter that have acoustic centers that coincide. Every speaker can be
idealized as a sound source acting at a single point. With non-concentric
designs, the two sound sources are separated by an appreciable distance,
and this distance interacts with the crossover to produce lobing in the
range where the driver's output overlaps. With a dual concentric design, the
two sources can be made to be very close or to even coincide.

Speakers like the KEF Q15 are true dual concentric designs. The tweeter is
built at the base of the woofer cone. Tannoy is famous for dual concentric
designs patterned after older designs by Altec Lansing. They place a
horn-loaded driver at the base of the woofer's cone and are thus
dual-concentric.

Since they avoid lobing, dual concentric designs are more tolerant of
various speaker placement alternatives, and are favored for near-field
listening.

loudspeaker stereo imaging
 

On Fri, 14 Nov 2003 09:24:23 -0500
"Arny Krueger" wrote:

With non-concentric
designs, the two sound sources are separated by an appreciable distance,
and this distance interacts with the crossover to produce lobing in the
range where the driver's output overlaps. With a dual concentric design, the
two sources can be made to be very close or to even coincide.

The theory is fine. its the practice that seems to be the problem IME.

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

loudspeaker stereo imaging
 

On Fri, 14 Nov 2003 09:24:23 -0500
"Arny Krueger" wrote:

With non-concentric
designs, the two sound sources are separated by an appreciable distance,
and this distance interacts with the crossover to produce lobing in the
range where the driver's output overlaps. With a dual concentric design, the
two sources can be made to be very close or to even coincide.

The theory is fine. its the practice that seems to be the problem IME.

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

loudspeaker stereo imaging
 

On Fri, 14 Nov 2003 08:51:45 +0000 (GMT)
Jim Lesurf wrote:

It *is* worth it if you can manage to get a clear image. Once achieved the
value becomes evident. :-)

Indeed ;-)

The problem is that really good stereo imaging
can be hard to obtain, hence is perhaps rarely experienced from domestic
'stereo' systems.

Its easy to obtain a stunning stereo image... wear headphones ;-)

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

loudspeaker stereo imaging
 

On Fri, 14 Nov 2003 08:51:45 +0000 (GMT)
Jim Lesurf wrote:

It *is* worth it if you can manage to get a clear image. Once achieved the
value becomes evident. :-)

Indeed ;-)

The problem is that really good stereo imaging
can be hard to obtain, hence is perhaps rarely experienced from domestic
'stereo' systems.

Its easy to obtain a stunning stereo image... wear headphones ;-)

--
Spyros lair: http://www.mnementh.co.uk/ |||| Maintainer: arm26 linux

Do not meddle in the affairs of Dragons, for you are tasty and good with ketchup.

loudspeaker stereo imaging
 

Jim Lesurf wrote:

Makes me wonder if all that stereo imaging stuff is worth the bother
(not that I bother, especially).

It *is* worth it if you can manage to get a clear image. Once
achieved the value becomes evident. :-) The problem is that really
good stereo imaging can be hard to obtain, hence is perhaps rarely
experienced from domestic 'stereo' systems.

I don't doubt that there are good and bad examples of imaging, and that
improvments can be made. :-) It was more that there seem to be physical
limits imposed by the wavelengths of certain frequencies, and the consquent
spacing of peaks and troughs - like the idea that a given frequency can
result in a peak at one ear and a trough at the other.


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

loudspeaker stereo imaging
 

Jim Lesurf wrote:

Makes me wonder if all that stereo imaging stuff is worth the bother
(not that I bother, especially).

It *is* worth it if you can manage to get a clear image. Once
achieved the value becomes evident. :-) The problem is that really
good stereo imaging can be hard to obtain, hence is perhaps rarely
experienced from domestic 'stereo' systems.

I don't doubt that there are good and bad examples of imaging, and that
improvments can be made. :-) It was more that there seem to be physical
limits imposed by the wavelengths of certain frequencies, and the consquent
spacing of peaks and troughs - like the idea that a given frequency can
result in a peak at one ear and a trough at the other.


--
Wally
www.makearatherlonglinkthattakesyounowhere.com
Things are always clearer in the cold, post-upload light.

loudspeaker stereo imaging
 

Ian Molton wrote:

On Fri, 14 Nov 2003 09:24:23 -0500
"Arny Krueger" wrote:

With non-concentric
designs, the two sound sources are separated by an appreciable distance,
and this distance interacts with the crossover to produce lobing in the
range where the driver's output overlaps. With a dual concentric design,
the two sources can be made to be very close or to even coincide.

The theory is fine. its the practice that seems to be the problem IME.

IMHO the proctice is fine. Tannoy dual concentrics have been used in pro
studios for over 40 years and they still sound wonderful.

Ian