Here's an article that appeared in the Nov 2004 issue of
Test & Measurement World, on Floyd Toole's speaker
performance tests.

http://www.reed-electronics.com/tmwo.../CA475937.html



--

-S
It's not my business to do intelligent work. -- D. Rumsfeld, testifying
before the House Armed Services Committee

Steven Sullivan wrote:

Here's an article that appeared in the Nov 2004 issue of
Test & Measurement World, on Floyd Toole's speaker
performance tests.

http://www.reed-electronics.com/tmwo.../CA475937.html

They still haven't quite caught on to how to design a speaker. They are
still restrained by standard "engineer think" as taught in college, with
their anechoic chambers and measurements of direct field frequency
response. Statements like "loudspeakers should be as neutral and
transparent as possible, and technical measurements should be able to
demonstrate whether they are or not" show no new thinking and no way out
of the hole they're in.

I had a continuing argument with Floyd Toole in the AES Journal about
his CRC experiments on evaluating speakers. My main complaint was that
he was only testing direct firing speakers, and drawing his conclusions
based on only that type of speaker. He was living in this microcosm of
real world speakers that were out there and making conclusions like
"speaker preference corellates with smoothness of frequency response on
axis, and how smooth it falls off when you go off axis." Plus, he was
using a room that was too small, and too dead to bring out most of the
off-axis consequences of speaker radiation patterns.

Now look at their comment about speaker design in this article. "That's
rubbish," said Toole. +/-3 db can be shrill, if a speaker's response
exhibits a midrange rise from -3 dB to +3 dB, or honky, if it exhibits a
+6-dB midrange peak in an otherwise flat response. In addition, a
+/-3-dB range can include many troubling, audible resonance points. If
you can't achieve a +/-3-dB spec, said Toole, "you're in deep trouble.
+/-3 dB is a giveaway. +/-2 is better, and if you reach +/-1, well, you
have my attention." But ultimately, he said, you don't need a single
spec--"You need a graph!" I know from all of my experience and speaking
with and reading many others, that the direct field response can be
varied all over the place and doesn't matter much, except for lateral
localization from the leading edge transients carried by the direct sound.

Sean Olive goes on about the power response: " 'not very. In fact, the
sound-power model suggests that if you turn a speaker around so it's
facing a wall you'll have the same listening experience, and we know
that's not the case.' Indeed, Olive has discovered a negative
correlation between CU's results and listener preferences and has
developed his own models (Ref. 2) that indicate what objective
measurements best correspond to subjective listener preferences." He
draws these conclusions based on his microcosm of listening to and
testing only these direct firing speakers!

One fellow, Devantier, found out that "The data he gathered (Ref. 3)
demonstrated that direct sound and early reflections¡ªwhich aren't
represented in a sound-power model¡ªare significant contributors to the
sound and spatial quality of a loudspeaker and that these contributors
must be represented in any objective model that purports to mimic
subjective experience." But instead of using that information to design
radiation patterns that take advantage of that, and believing that sound
power response is not related to speaker preference, he concludes that
consumer loudspeakers are a case "where you have a 4¦Ð environment and
know you want to minimize room effects."

They are doing all of these experiments, measuring all of these factors,
but making conclusions without a model of subjective loudspeaker
performance that correlates to live sound. They are assuming the
"engineer think" model of "accuracy" and smooth frequency response, then
doing experiments that prove only that factor, and drawing conclusions
based on these entering assumptions. That is circular reasoning of the
highest order.

Take, as just one example, our discussion above of the sonic effect of
Linkwitz's Orion design. Most contributors stated and knew that the
dipolar pattern of the speaker contributed immensely to its sound,
especially the soundstaging. A side benefit of this multi-directional
pattern is that it makes the instruments sound more real, more detached
from the speakers themselves, more right there in the room with you.
This is an enormous realization, something that must be studied and
taken into account in any loudspeaker research or design program. I
don't think that the Canadians have caught on to that yet.

To prove me wrong, I want to see some speakers coming out of Harman with
radiation patterns other than direct firing, with all of the drivers on
one side of the box. I don't really know if they do have such a thing or
not - even maybe just a tweeter on the back a'la Snell, but I somehow
doubt it. Someone please educate me if I'm wrong.

Gary Eickmeier

On 24 Feb 2005 01:03:13 GMT, Gary Eickmeier
wrote:

A side benefit of this multi-directional
pattern is that it makes the instruments sound more real, more detached
from the speakers themselves, more right there in the room with you.

This is debatable. You are describing a common and valid observation
but how real or accurate that representation is is not yet verified.

To prove me wrong, I want to see some speakers coming out of Harman with
radiation patterns other than direct firing, with all of the drivers on
one side of the box. I don't really know if they do have such a thing or
not - even maybe just a tweeter on the back a'la Snell, but I somehow
doubt it. Someone please educate me if I'm wrong.

The Revel Ultima Studios and Salons from the Harmon conglomerate have
a rear-firing tweeter "that flattens the 'in-room' response, resulting
in superior 'air' and detail."

Kal

Gary Eickmeier Said:


To prove me wrong, I want to see some speakers coming out of Harman
with
radiation patterns other than direct firing, with all of the drivers on

one side of the box. I don't really know if they do have such a thing
or
not - even maybe just a tweeter on the back a'la Snell, but I somehow
doubt it. Someone please educate me if I'm wrong.


I respond:

Perhaps nobody wants to get involved in the likely lawsuit with Bose,
should somebody else want to design a GOOD direct/reflecting speaker.

Gary Eickmeier wrote:
Steven Sullivan wrote:

Here's an article that appeared in the Nov 2004 issue of
Test & Measurement World, on Floyd Toole's speaker
performance tests.

http://www.reed-electronics.com/tmwo.../CA475937.html

They still haven't quite caught on to how to design a speaker. They are
still restrained by standard "engineer think" as taught in college, with
their anechoic chambers and measurements of direct field frequency
response. Statements like "loudspeakers should be as neutral and
transparent as possible, and technical measurements should be able to
demonstrate whether they are or not" show no new thinking and no way out
of the hole they're in.

I had a continuing argument with Floyd Toole in the AES Journal about
his CRC experiments on evaluating speakers. My main complaint was that
he was only testing direct firing speakers, and drawing his conclusions
based on only that type of speaker. He was living in this microcosm of
real world speakers that were out there and making conclusions like
"speaker preference corellates with smoothness of frequency response on
axis, and how smooth it falls off when you go off axis." Plus, he was
using a room that was too small, and too dead to bring out most of the
off-axis consequences of speaker radiation patterns.

Now look at their comment about speaker design in this article. "That's
rubbish," said Toole. +/-3 db can be shrill, if a speaker's response
exhibits a midrange rise from -3 dB to +3 dB, or honky, if it exhibits a
+6-dB midrange peak in an otherwise flat response. In addition, a
+/-3-dB range can include many troubling, audible resonance points. If
you can't achieve a +/-3-dB spec, said Toole, "you're in deep trouble.
+/-3 dB is a giveaway. +/-2 is better, and if you reach +/-1, well, you
have my attention." But ultimately, he said, you don't need a single
spec--"You need a graph!" I know from all of my experience and speaking
with and reading many others, that the direct field response can be
varied all over the place and doesn't matter much, except for lateral
localization from the leading edge transients carried by the direct sound.

Sean Olive goes on about the power response: " 'not very. In fact, the
sound-power model suggests that if you turn a speaker around so it's
facing a wall you'll have the same listening experience, and we know
that's not the case.'

Indeed, Olive has discovered a negative
correlation between CU's results and listener preferences and has
developed his own models (Ref. 2) that indicate what objective
measurements best correspond to subjective listener preferences." He
draws these conclusions based on his microcosm of listening to and
testing only these direct firing speakers!

One fellow, Devantier, found out that "The data he gathered (Ref. 3)
demonstrated that direct sound and early reflections??which aren't
represented in a sound-power model??are significant contributors to the
sound and spatial quality of a loudspeaker and that these contributors
must be represented in any objective model that purports to mimic
subjective experience." But instead of using that information to design
radiation patterns that take advantage of that, and believing that sound
power response is not related to speaker preference, he concludes that
consumer loudspeakers are a case "where you have a 4?? environment and
know you want to minimize room effects."

They are doing all of these experiments, measuring all of these factors,
but making conclusions without a model of subjective loudspeaker
performance that correlates to live sound. They are assuming the
"engineer think" model of "accuracy" and smooth frequency response, then
doing experiments that prove only that factor, and drawing conclusions
based on these entering assumptions. That is circular reasoning of the
highest order.


No, because they're taking it one step further -- actual listening tests
with actual listeners and actual speakers (AIUI, from different manufacturers,
not just Harman/JBL). It may be that they aren't trying all the
various speaker 'topologies' that are out there -- but it seem to me
they're trying hard to draw reliable conclusions from the sample
set they *do* use.

Having not seen Olive's or Toole's actual papers from 2004,
I can't say how much they've generalized their conclusions.


Take, as just one example, our discussion above of the sonic effect of
Linkwitz's Orion design. Most contributors stated and knew that the
dipolar pattern of the speaker contributed immensely to its sound,
especially the soundstaging. A side benefit of this multi-directional
pattern is that it makes the instruments sound more real, more detached
from the speakers themselves, more right there in the room with you.

Perhaps, but, that conclusion hasn't been formalized nearly as rigorously
as Olive/Toole's, has it?

This is an enormous realization, something that must be studied and
taken into account in any loudspeaker research or design program. I
don't think that the Canadians have caught on to that yet.

See above.


To prove me wrong, I want to see some speakers coming out of Harman with
radiation patterns other than direct firing, with all of the drivers on
one side of the box. I don't really know if they do have such a thing or
not - even maybe just a tweeter on the back a'la Snell, but I somehow
doubt it. Someone please educate me if I'm wrong.

I would only want to see that if Harman had in fact tested that
speaker topology properly in their setup. If they do so and find
the topology wanting, and can provide data indicating why this is
so, I wouldn't expect them to sell such speakers.

Has anyone asked Toole/Olive/etc *recently* if and why they aren't fans of
non-direct radiator designs?


--

-S
It's not my business to do intelligent work. -- D. Rumsfeld, testifying
before the House Armed Services Committee

Gary Eickmeier wrote:

They are doing all of these experiments, measuring all of these
factors,
but making conclusions without a model of subjective loudspeaker
performance that correlates to live sound.

Neither is anyone else. What Harman is doing is trying to make
loudspeakers that correlate to *something*--namely, listener
preferences, determined with at least some scientific rigor.

They are assuming the
"engineer think" model of "accuracy" and smooth frequency response,
then
doing experiments that prove only that factor, and drawing
conclusions
based on these entering assumptions. That is circular reasoning of
the
highest order.

Not circular at all, unless you can show that their subjective
evaluation method predisposes test subjects to prefer accurate
speakers.

Now, it may be that they are only testing one type of speaker, and
within that category accuracy correlates best with listener
preferences. Perhaps if they threw some planars, the Orions, or Bose
901s into the mix, they'd discover that there are factors that outweigh
accuracy in listeners' minds. (Perhaps, too, they already have. I don't
think they reveal what speakers they test.) But somebody needs to do
that work. To just say, "Unidirectional speakers aren't good, and
therefore any test that shows them to be good is flawed" is to stand on
very shaky ground.

bob

wrote in message ...
Gary Eickmeier wrote:

They are doing all of these experiments, measuring all of these
factors,
but making conclusions without a model of subjective loudspeaker
performance that correlates to live sound.

Neither is anyone else. What Harman is doing is trying to make
loudspeakers that correlate to *something*--namely, listener
preferences, determined with at least some scientific rigor.

They are assuming the
"engineer think" model of "accuracy" and smooth frequency response,
then
doing experiments that prove only that factor, and drawing
conclusions
based on these entering assumptions. That is circular reasoning of
the
highest order.

Not circular at all, unless you can show that their subjective
evaluation method predisposes test subjects to prefer accurate
speakers.

Now, it may be that they are only testing one type of speaker, and
within that category accuracy correlates best with listener
preferences. Perhaps if they threw some planars, the Orions, or Bose
901s into the mix, they'd discover that there are factors that outweigh
accuracy in listeners' minds. (Perhaps, too, they already have. I don't
think they reveal what speakers they test.) But somebody needs to do
that work. To just say, "Unidirectional speakers aren't good, and
therefore any test that shows them to be good is flawed" is to stand on
very shaky ground.

Gary didn't say that. He said that Floyd Tool and his gang at Harmon have
to the best of his knowledge limited themselves to unidirectional speakers.
Therefore their conclusions are of necessity somewhat circumscribed, and it
may be in fact that if bi-polar or omidirectional speakers were tested, and
the test setup provided them the proper configuration and environment, that
they may very well be preferred over "flat and neutral" direct firing
speakers. At least he believes they will. Finally, he thinks the engineers
at Harman are missing this possibility given their long developmental
history of dealing with only unidirectional speakers.

wrote:

Now, it may be that they are only testing one type of speaker, and
within that category accuracy correlates best with listener
preferences. Perhaps if they threw some planars, the Orions, or Bose
901s into the mix, they'd discover that there are factors that outweigh
accuracy in listeners' minds. (Perhaps, too, they already have. I don't
think they reveal what speakers they test.) But somebody needs to do
that work. To just say, "Unidirectional speakers aren't good, and
therefore any test that shows them to be good is flawed" is to stand on
very shaky ground.

Just a couple of quick observations for you to chew on:

First, we are not "doing" accuracy with the loudspeaker end of the
reproduction chain, in the same sense that we think of with amplifiers
or sources. Suppose, for example, that we agree that reproducing a two
channel recording using some signal processing and surround speakers
sounds better than doing it with just two speakers. Many of you reading
this would agree with that, so not too radical so far. But if we were to
measure the resultant sound with any system you can think of, the
frequency response and phase and timing of all of the room effects would
drive the "engineer think" mind crazy.

Second, they seem to be completely ignoring the Bose research that
showed that power response IS extremely important, and that the spatial
nature of sound is perhaps even more important than the frequency
response as measured on axis in an anechoic chamber. Mark Davis's work,
which led to an amazing speaker called the DBX Soundfield One, found
that the audible characteristics of speakers are the dynamic radiation
pattern and frequency response in all directions. That being the case, a
speaker designer who didn't take radiation pattern into account in his
design would be ignoring half of the factors that contribute to
audibility of differences between speakers, or their relationship to the
live event.

The answer, as I have stated many times in this and other forums, is to
focus on the image model of the live sound vs the reproduction. An image
model is just a plan view of the speakers (or instruments) and all of
their reflections, or reflected images, in the surrounding walls. If the
image model of the reproduction soundfield can be made to come closer to
that of the live situation, it will sound more like it, and therefore
more real. To design speakers, therefore, you work backward from such an
image model to the radiation pattern required to accomplish it. This
makes the loudspeaker, in effect, an Image Model Projector, using the
whole room and its surfaces to create its sound.

I could tell this to the Harman people point blank, in so many words,
and it would go right over their heads, because it doesn't jibe with
anything they teach in engineering school.

And yes, you could build a better direct and reflecting type of speaker
if you tried hard enough, and no, Bose has no patent on a radiation
pattern. Here is a picture of an attempt at such a speaker

http://www.pbase.com/eickmeier/image/712286

It is just a little particle board and Radio Shack speakers and
crossovers, but it satisfied me that the radiation pattern alone could
make it sound pretty good, in spite of the (intentionally) cheap
components. I'm also not convinced that I achieved my radiation pattern
that I was after, but I have no way to measure or pursue that.

Gary Eickmeier

On missing the point -- I read the article in T&M when it showed up last
fall -- the point that the T&M authors make is that "golden ears" and
trained "neophyte ears" have the same outcomes when it comes to the judging
the merit -- it's all about the statistics.

"Steven Sullivan" wrote in message
...
Here's an article that appeared in the Nov 2004 issue of
Test & Measurement World, on Floyd Toole's speaker
performance tests.

http://www.reed-electronics.com/tmwo.../CA475937.html



--

-S
It's not my business to do intelligent work. -- D. Rumsfeld, testifying
before the House Armed Services Committee

Harry Lavo wrote:

Gary ... said that Floyd Tool and his gang at Harmon have
to the best of his knowledge limited themselves to unidirectional
speakers.
Therefore their conclusions are of necessity somewhat circumscribed,
and it
may be in fact that if bi-polar or omidirectional speakers were
tested, and
the test setup provided them the proper configuration and
environment, that
they may very well be preferred over "flat and neutral" direct firing
speakers. At least he believes they will. Finally, he thinks the
engineers
at Harman are missing this possibility given their long developmental
history of dealing with only unidirectional speakers.


Based on Dr. Toole's own comments during a CEDIA presentation I
attended, plus what I've inferred from reading this article, there is
nothing about Harmon's experiments that specifically restricts them
from including non-unidirectional speakers...and moreover, should they
include non-unidirectional in their test, it appears quite clear that
the criteria by which listener's find a speaker preferrable would also
apply to all speakers regardless of their readiation pattern.

In a pathetically oversimplified nutshell, Harmon/Toole is saying that
the SUM of a speaker's direct response and the indirect room response
should be smooth and (relatively) flat in order for listener's to find
that speaker's sound appealing.

So why shouldn't we believe the same will hold true for a speaker that
just happens to intentionally put more energy off-axis? The listener
will still perceive some direct sound, and the listener will still
perceive the indirect room response. Based on Harmon's experiments the
speakers (unidirectional, bipolar, omnidirectional, or whatever) whose
SUMMED direct & indirect outputs are smoothest will be perceived as
most pleasurable to listen to.

Gary's complaint seems a bit of a strawman, IMHO.

Gary Eickmeier wrote:
They are still restrained by standard "engineer think" as taught in
college, with their anechoic chambers and measurements of direct field
frequency
response.

I don't normally participate in these threads but your statements are
such a misreprentation of the facts stated in our research findings
that I must step in and correct you.

I would encourage you to first read the AES papers instead of
speculating on what speakers, rooms and measurements were used. The
information is all contained in the references listed at the end of the
Test & Measurement World article.

We measure loudspeakers in anechoic chambers because it is the only
place you can accurately measure and predict the qualities of the
direct, early-reflected and reverberant sounds produced by the
loudspeaker in a room. Neither in-room or sound power measurements can
do this. In reference 5 of the T&MW story I developed and compared
preference models based on in-room and sound power loudspeaker
measurements. They both produced less accurate predictions of
loudspeaker preference ratings than a model based on our set of
spatially-averaged anechoic measurements. Contrary to your statements,
the quality of the direct sound was found to be an important predictor
of loudspeaker preference in addition to off-axis response and bass
performance.
Both sound power and in-room measurements cannot accurately show these
things separately. Clearly the room acoustics/ speaker directivity are
important variables that will be addressed in the next phase of
research.

Statements like "loudspeakers should be as neutral and
transparent as possible, and technical measurements should be able to
demonstrate whether they are or not" show no new thinking and no way
out
of the hole they're in.
Wow! I have been telling our competitors something this for years.
Please listen up competitors: qualities such as transparency,
neutrality are all money-losing,outdated performance targets that "show
no new thinking". Models that predict consumer preference ratings
based on measurements are also a huge waste of time & money that will
put you further into "the hole ". The money you save not fixing those
nonlinearities can be redirected towards more important factors such as
side-firing multi-directivity loudspeakers highly preferred by
listeners...

Hedraws these conclusions based on his microcosm of listening to and
testing only these direct firing speakers!

The generalized model I show in reference 5 was based on listening
tests performed on 70 different loudspeaker models sampled from a wide
range of prices, brands,countries of origin and directivity. While the
vast majority were front-firing designs some designs included horns,
dipoles, bipoles, side-firing/rear-firing tweeters, omni-directional
patterns. Front-firing speakers represent the vast majority of most
speakers sold; it's not "just a Canadian thing..", it's an
International thing. Our test sample reflected this reality.
Directivity was not a good predictor of preference, indicating that you
need to get the frequency response correct first.


A side benefit of this multi-directional
pattern is that it makes the instruments sound more real, more detached
from the speakers themselves, more right there in the room with you.
This is an enormous realization, something that must be studied and
taken into account in any loudspeaker research or design program. I
don't think that the Canadians have caught on to that yet.

The cause and effect for this are well-known. Wider-dispersion speakers
can produce stronger side wall lateral reflections that create more
decorrelated signals at the ears. This creates a sense of spaciousness
and envelopment, also characteristic of rectangular shaped concert
halls. I frankly do not see the need for side-firing patterns given
today's 5.1 and 7.1 setups where the additional side surround speakers
can produce the same envelopment cues, so long as the recording
engineer puts them in the mix. There is another reason why
multi-directional speakers are not so ideal. 99% of the
recordings/films are mixed on direct radiator front-firing
loudspeakers. In fact it is embodied in the music recording industry
guidelines on how to record and mix surround music (see
http://www.grammy.com/pe_wing/5_1_Rec.pdf). If consumers want to better
hear what the artist intended then they would be wise to use similar
speakers at home. Fortunately, most consumers already do.

Cheers,
Sean Olive
Mananger Subjective Evaluation, R&D Group
Harman International

Gary Eickmeier wrote:
This is an enormous realization, something that must be studied and
taken into account in any loudspeaker research or design program. I
don't think that the Canadians have caught on to that yet.

Then how do explan Mirage and Paradigm's current and/or previous
bipolar/omnidirectional offerings, e.g. Mirage OM line or Paradigm Esprit
BP? And Paradigm's current Reference and Signature surrounds have drivers
on multiple sides.

--
Jason Kau
IS FOR EMAIL
IS FOR SPAM
http://www.cnd.gatech.edu/~jkau

Steven Sullivan wrote:
Has anyone asked Toole/Olive/etc *recently* if and why they aren't fans of
non-direct radiator designs?

It is dated "31 January, 2002", but they write about that in
http://www.harman.com/wp/index.jsp?articleId=120
http://www.harman.com/wp/pdf/Loudspeakers&RoomsPt1.pdf
Pages 9 and following.

--
http://www.mat.uc.pt/~rps/

..pt is Portugal| `Whom the gods love die young'-Menander (342-292 BC)
Europe | Villeneuve 50-82, Toivonen 56-86, Senna 60-94

Harry Lavo wrote:
wrote in message ...

Perhaps if they threw some planars, the Orions, or Bose
901s into the mix, they'd discover that there are factors that outweigh
accuracy in listeners' minds. (Perhaps, too, they already have. I don't
think they reveal what speakers they test.)

They don't reveal specifically which speakers they test, but they mention,
in general terms, some kinds of speakers they have tested.

Finally, he thinks the engineers
at Harman are missing this possibility given their long developmental
history of dealing with only unidirectional speakers.

http://www.harman.com/wp/index.jsp?articleId=121
http://www.harman.com/wp/pdf/Loudspeakers&RoomsPt2.pdf

Page 17:

"Four expensive and highly regarded loudspeakers are evaluated in
the shuffler room, in a double-blind test."

"A Mountain Skyline: $5000/pr

This speaker has a bunch of things going on. Clearly the designers
didn t believe that flat was necessary, or they didn't know how to
achieve it. Not only are the general trends not flat, but superimposed
are peaks and dips suggesting resonances. The proof that they are
resonances is in the fact that the patterns are repeated in all of
the curves. The directivity is interesting, being zero up to 100
Hz (the woofer) and then abruptly rising to about 5 dB and hovering
around that all the way to 20 kHz.

Since 4.8 dB is the directivity of a dipole, we could suspect that
this is a hybrid system with a panel loudspeaker operating above
about 100 Hz. The woofer exhibits a significant bump and then rolls
off below about 60 Hz. No subwoofing here."

You can speculate which "highly regarded loudspeaker" costs about
$5000/pr and has a panel loudspeaker plus woofer.

--
http://www.mat.uc.pt/~rps/

..pt is Portugal| `Whom the gods love die young'-Menander (342-292 BC)
Europe | Villeneuve 50-82, Toivonen 56-86, Senna 60-94

Gary Eickmeier wrote:
wrote:

Now, it may be that they are only testing one type of speaker, and
within that category accuracy correlates best with listener
preferences. Perhaps if they threw some planars, the Orions, or Bose
901s into the mix, they'd discover that there are factors that outweigh
accuracy in listeners' minds. (Perhaps, too, they already have. I don't
think they reveal what speakers they test.) But somebody needs to do
that work. To just say, "Unidirectional speakers aren't good, and
therefore any test that shows them to be good is flawed" is to stand on
very shaky ground.

Just a couple of quick observations for you to chew on:

First, we are not "doing" accuracy with the loudspeaker end of the
reproduction chain, in the same sense that we think of with amplifiers
or sources. Suppose, for example, that we agree that reproducing a two
channel recording using some signal processing and surround speakers
sounds better than doing it with just two speakers. Many of you reading
this would agree with that, so not too radical so far. But if we were to
measure the resultant sound with any system you can think of, the
frequency response and phase and timing of all of the room effects would
drive the "engineer think" mind crazy.

Second, they seem to be completely ignoring the Bose research that
showed that power response IS extremely important, and that the spatial
nature of sound is perhaps even more important than the frequency
response as measured on axis in an anechoic chamber. Mark Davis's work,
which led to an amazing speaker called the DBX Soundfield One, found
that the audible characteristics of speakers are the dynamic radiation
pattern and frequency response in all directions. That being the case, a
speaker designer who didn't take radiation pattern into account in his
design would be ignoring half of the factors that contribute to
audibility of differences between speakers, or their relationship to the
live event.

The answer, as I have stated many times in this and other forums, is to
focus on the image model of the live sound vs the reproduction. An image
model is just a plan view of the speakers (or instruments) and all of
their reflections, or reflected images, in the surrounding walls. If the
image model of the reproduction soundfield can be made to come closer to
that of the live situation, it will sound more like it, and therefore
more real. To design speakers, therefore, you work backward from such an
image model to the radiation pattern required to accomplish it. This
makes the loudspeaker, in effect, an Image Model Projector, using the
whole room and its surfaces to create its sound.

I could tell this to the Harman people point blank, in so many words,
and it would go right over their heads, because it doesn't jibe with
anything they teach in engineering school.

Well, that's a curious claim , because Toole et al. are *deeply* into surround
sound these days. Apaprently it has not driven their 'engineer think'
minds crazy.

e.g.

http://www.harman.com/wp/index.jsp?articleId=120




--

-S
It's not my business to do intelligent work. -- D. Rumsfeld, testifying
before the House Armed Services Committee

John Walton wrote:
On missing the point -- I read the article in T&M when it showed up last
fall -- the point that the T&M authors make is that "golden ears" and
trained "neophyte ears" have the same outcomes when it comes to the judging
the merit -- it's all about the statistics.


So, who, pray tell, is missing the point?



"Steven Sullivan" wrote in message
...
Here's an article that appeared in the Nov 2004 issue of
Test & Measurement World, on Floyd Toole's speaker
performance tests.

http://www.reed-electronics.com/tmwo.../CA475937.html



--

-S
It's not my business to do intelligent work. -- D. Rumsfeld, testifying
before the House Armed Services Committee


--

-S
It's not my business to do intelligent work. -- D. Rumsfeld, testifying
before the House Armed Services Committee

I am still using a pair of DBX Soundfield One speakers. Each tower has
14 drivers. Four 10" woofers (one on each side), four mid range and 6
tweeters in a hex pattern. They provide a very airy and balanced sound
by reflecting off of the walls.


---MIKE---

Jason Kau wrote:
Gary Eickmeier wrote:

This is an enormous realization, something that must be studied and
taken into account in any loudspeaker research or design program. I
don't think that the Canadians have caught on to that yet.


Then how do explan Mirage and Paradigm's current and/or previous
bipolar/omnidirectional offerings, e.g. Mirage OM line or Paradigm Esprit
BP? And Paradigm's current Reference and Signature surrounds have drivers
on multiple sides.

By "Canadians" I am just referring to the CRC research program, not
Canadian speaker makers. I think the Mirages help prove my points.

Gary Eickmeier

Sean,

I would be more interested in your reaction to my second post, the one
on the 24th at 9PM. It does a better job of bypassing all of the
chit-chat and suggesting some avenues of research that are perhaps
different from what you are used to. Also shows a picture of my speaker
that I made some 15 years ago. And no, I am not trying to hawk something
- I am basically a failed industrial designer (career got sidetracked in
the Air Force during Viet Nam era) and am doing more with photography
and video than audio. I haven't been able to pursue my big ideas because
I don't know much about building, measuring, and re-building the damn
things. My engineer friends aren't all that interested in developing
someone else's ideas either.

But I would be interested in your reaction to my ideas. I never could
get Floyd's complete attention, because he was always so busy. I respect
his vast knowledge and fastidiousness, but sometimes (back when I was
into all this stuff) I wanted to just stand in front of him and say STOP
IT! Stop all this conventional thinking about measurement, accuracy,
resonances, directivity, decreasing the effects of reflections in rooms
- reformat and reprogram.

For your inspiration read the original Bose research paper, where they
went into the concert hall and discovered the spatial nature of sound
and its importance; read Mark Davis's paper on the Soundfield One; some
of Dave Moulton's work, Art Benade's "From Instrument to Ear in a Room:
Direct or Via Recording," and then, if you're not howling with laughter
yet, my magnum opus at

http://aes.org/publications/preprint...nts_search.cfm

Finally, here is a paradigm for you to think about: take three perfectly
omnidirectional loudspeakers into a good sounding concert hall. These
will represent typical instruments or sound sources (perfect point
source and all that). Place them at stage left, center, and right, run a
series of test signals thru them so that you know exactly what is going
into them - signals such as pink noise, impulses, and some steady tones.
Measure everything you want about the resultant sound from back in a
good seat in the audience, and also make a binaural recording from that
spot. This is your reference source. Now record the output of that setup
with typical modern recording methods such as John Eargle might use.
This is your reference recording. Now, take that recording into a home
type listening room and reproduce it with speakers of various designs,
looking for which ones come closest to both the measurements taken in
the concert hall of the original, and the binaural recording of the
original. You can even make a new binaural recording of the playback and
compare it with the original one. Measure the IACC with a binaural head
at the listening position and graph it. Compare that with the concert
hall measurement. Measure the direct to reflected ratios in the two
spaces. All of these things are related mainly to audibility of
differences between the live event and the playback, and NOT to accuracy
as compared to a RECORDING. That is the difference in direction I would
propose for your company or any other that wants to try something
different from the same old same old.

Of course, it has all been done before, but not everyone agrees with the
type of speaker that resulted from it...

Gary Eickmeier