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The Goals for an "Ideal Loudspeaker"


Zilch

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You state the obvious; I can certainly hear a modal peak as I already stated.

It would help if you used a few more words to explain yourself.

The mechanisms are different above and below the transition frequency. The fact that we can't "hear through" what the room does to longer-wavelength low frequencies is not evidence that this does not occur, comprehensively, even, at higher ones.

This one's tough, and it's the stuff of contention whenever subjectivity enters the picture. Are our capacitors undergoing "break-in," or are we just getting used to them? For every party that prefers speaker A to speaker B, there's a B-lover who'll tell us A sounds like crap, which is why only A/B testing under identical conditions provides any hope of subjectively discerning the difference, and even then, it must be independent, blind, and statistical. In the end, the preference differential may relate more to meaning than substance.... :(

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Here's a link to another paper, in power point format, on adaptation - fascinating:

http://www.davidgriesinger.com/binaural_hearing.ppt

"One's own equal loudness contour often sounds smoother and more natural than realistic reproduction."

"But adaptation will continue to work, ... and they will soon not notice the difference...."

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I'd like to back up here and ask a simpler question (perhaps I should start another thread) concerning something that I noticed years ago. There are speakers that clearly sound like music coming out of a box, for me Advents and ARs were in the long list of speakers with this quality years ago when I first heard them, Dynaco A-25s and EPI100s less so back in the day. Then there are others, often audiophile speakers that disappear, one - they do not sound like music from a woofer and tweeter (not well integrated) and even better the speaker seems to vanish - no box, perhaps close enough reproduction to trick the ear-brain into thinking that the music is here in the room.

You guys have been busy overnight!

Speakers disappearing can be simply a matter of total directivity. I tend to like a speaker with a more focused soundfield. In crossover design better summing of drivers always lends the system a more focused sound. I even recall a system with a slight flare to the tweeter mounting and the grille continued that flare. It gave a very focused sound. I liked it but a colleague thought it was too direct. "Close your eyes and you always know where the speaker is."

This is true, there is an inherent compromise between directness or focus and diffusion and spaciousness. Once you define the number of channels you have to pick your poison on that continuum. John Crabbe gave a famous review of the Bose 901 where he said they gave a nice spaciousness to the orchestra, but when the piano came in it was 20 ft wide. Even mono material had the same width. With headphones on, flip between mono and stereo. The difference is always huge. With different speakers, or different positions in the room, do the same test. If it is hard to tell the difference between mono and stereo you are leaning towards the spaciousness end of things.

The only answer is to have more channels and then use more directional speakers or a deader room. (Come comrades, let us sing...)

I think the "every reflection has to have the same spectrum" notion is an ideal not proven.

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Let me just summarize by saying that I think it is absurd to claim that we are able to adapt to any room, even most home listening rooms especially if you allow the speakers to be placed where people want them rather than the ideal locations. Bass management/correction and multiple sub solutions are further evidence that full adaptation is not possible.

I think the Toole paper was trying to show that your rank ordering of speakers wasn't strongly effected by the room. We worried about the same thing at KEF. That is where the University of Denmark, Soren Bech studies came from.

Concept: what if the room and speaker added in such a way that bad room A plus bad speaker B perfectly corrected each other and made a good combination. We wouldn't be able to design a "better" speaker, only speakers that suited particular rooms. It was important (and a relief) to find that the ranking of systems was preserved between various rooms.

The adaptation went both ways. If you stayed in one room and switched speakers you heard the difference between speakers. If you used binaural recording you could "stick with" one speaker and switch amongst rooms. Then you clearly heard the difference between rooms (primarily as a bottom end effect).

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You guys aren't the only ones discussing speakers and rooms.....

http://www.diyaudio.com/forums/multi-way/1...oom-system.html

Over 1400 posts and 50,000 views. Much of this deals with compromises between the former and latter. Understood, the discussion here may be more focused towards the speaker that is room independent......

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Adaptation is a fascinating subject and I have not seen a lot written about it. I noticed the effect myself however it was not fast, not moment to moment. I often find in store show rooms, or at shows that when I first walk into the room the sound is quite bad to me, then if I leave and come back a while later it seems that perhaps some adaptation has taken place.

My experience has not been like that at all. If I walk into a speaker demo and my first impression is that the sound is either good or bad, that never changes on a return trip. I do find that I become better able to ignore differences between different "good" speakers, and that could be adaptation, but I've never revised an initial bad impression on a subsequent hearing.

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My experience has not been like that at all. If I walk into a speaker demo and my first impression is that the sound is either good or bad, that never changes on a return trip. I do find that I become better able to ignore differences between different "good" speakers, and that could be adaptation, but I've never revised an initial bad impression on a subsequent hearing.

I find that it usually happens when there is a speaker that I am interested in so I stay and listen for

some time the first time. Not sure what happens if you don't stay long enough.

I believe that Paul Barton also mentions adaptation briefly toward the end of this interview, with

regard to the NRC, about 2/3 - 3/4 way in:

http://twit.tv/htg16

He says that in controlled tests with new listeners, the first 40 minutes they were hearing the room,

take a break, and second round they do much better being able to filter out (some - my interpretation)

the room effects.

I noticed this probably 5 or 10 years ago and often wondered why people didn't talk about it more.

Actually, I notice long before that most small listening rooms did not sound good on the first listen,

larger ones were not as bad, later I noticed the improvement with small rooms on a second visit.

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I noticed this probably 5 or 10 years ago and often wondered why people didn't talk about it more.

Actually, I notice long before that most small listening rooms did not sound good on the first listen,

larger ones were not as bad, later I noticed the improvement with small rooms on a second visit.

I can see how that might apply for being able to characterize a sound. With longer listening I can certainly do a better job of telling you why I think a good sound is good or a bad sound is bad. But time never makes a bad sound seem any better to me. At best it becomes less irritating and more tolerable. I have never had the experience of deciding that something I thought sounded bad at first was good on a repeat hearing. OTOH, I have had the experience of noticing problems with something that sounded pretty good to ma at first when hearing it again. My good first impressions may lessen on a second hearing, but my bad ones always remain bad.

BTW, I find this also seems to be true for visuals, like looking at TV sets,

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You guys have been busy overnight!

This is fun stuff, irresistible to speakergeeks.

We each come to this subject with a frame of reference, and conventional wisdom tells us that an ideal loudspeaker is an unattainable objective:

1) Every room is different, and

2) Everyone hears differently.

Toole, however, teaches us to parse speaker, room, and listener, and to analyze them each as independent variables. With this insight, it becomes readily apparent that the task may not be so impossible to accomplish as we first believed.

This simple exercise in clarity of thought also illuminates a stunning proposition, namely, that those characteristics of loudspeakers which confer room independence and excellence of performance might well be exploitable in this quest:

In spite of the incomplete state of this area of work,

there remains one compelling result: when given a chance

to compare, listeners sat down in four different rooms and

reliably rated three loudspeakers in terms of sound quality.

Now we need to understand what it is about those loudspeakers

that caused some to be preferred to others. If that

is possible, it suggests that by building those properties

into a loudspeaker, one may have ensured that it will

sound good in a wide variety of rooms; a dream come true.

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This is fun stuff, irresistible to speakergeeks.

We each come to this subject with a frame of reference, and conventional wisdom tells us that an ideal loudspeaker is an unattainable objective:

1) Every room is different, and

2) Everyone hears differently.

Toole teaches us to parse speaker, room, and listener, and to analyze them each as independent variables. With this insight, it becomes readily apparent that the task may not be so impossible to accomplish as we first believed.

This simple exercise in clarity of thought also illuminates a stunning proposition, namely, that those characteristics of loudspeakers which confer independence and excellence of performance might well be exploitable in this quest:

Toole's quote is compelling. However, wasn't it written quite some time ago 10+ years??? If so, then why hasn't the next step he described regarding evaluating the test speakers and then building the 'ideal' one? As Soundminded has pointed out elsewhere, the ideal loudspeaker won't be built because it would put an abrupt end to the marketing lifecycle of 'new and improved'.

Admittedly, it's a fun exercise, this journey towards the ideal loudspeaker. However, at some point along the way disallusionment will set in or, interest in another hobby will surface and take over one's time.......

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Toole's quote is compelling. However, wasn't it written quite some time ago 10+ years??? If so, then why hasn't the next step he described regarding evaluating the test speakers and then building the 'ideal' one?

Nobody suggested it would be easy.

The performance characteristics developed in the T&O metric are widely accepted today, and I believe we can credibly argue that the results are improved designs.

Soundminded (and I believe Ken, also) would observe that fundamental paradigm is wrong, even though we may be doing a better job with it. However, ask SM if his approach isn't also room-independent.

Admittedly, it's a fun exercise, this journey towards the ideal loudspeaker. However, at some point along the way disallusionment will set in or, interest in another hobby will surface and take over one's time.......

Clearly, there are exceptions.... :(

Edit: Here, max dispersion for $12; get busy and discover the answers:

post-102716-1272486264.jpg

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Actually, I notice long before that most small listening rooms did not sound good on the first listen, larger ones were not as bad, later I noticed the improvement with small rooms on a second visit.

In keeping with the theories documented here, if you're talking larger in width, the longer differential delay times would reduce the influence of early lateral reflections upon spectral balance and timbre.

Interestingly, the further back we get from the speakers, the shorter the differential delays become, the early reflections become more prominent in the "mix," and the worse the speakers should sound.... :(

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http://www.aes.org/e-lib/browse.cfm?elib=1403

http://www.aes.org/e-lib/browse.cfm?elib=14941

http://www.aes.org/e-lib/browse.cfm?elib=1433

http://www.aes.org/e-lib/browse.cfm?elib=4464

Last, but not least, here's a pretty solid overview of the history of loudspeaker design, through the lens of JBL's Mark Gander.

http://www.aes.org/e-lib/browse.cfm?elib=12162

I wish I could post the actual papers, but they are copyrighted.

-k

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In keeping with the theories documented here, if you're talking larger in width, the longer differential delay times would reduce the influence of early lateral reflections upon spectral balance and timbre.

Interestingly, the further back we get from the speakers, the shorter the differential delays become, the early reflections become more prominent in the "mix," and the worse the speakers should sound.... :(

You know Zilch, I am aware that you wish to remain anonymous and I respect that and this is often taken the wrong way but have you ever worked professionally in loudspeaker design or any sort of engineering? Are you a name that we would recognize? There are many who are annoyed by my asking this sort of question but I just want to get a better understanding of your perspective and experience. This has nothing to do with the who has better credentials sort of thing.

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Nobody suggested it would be easy.

The performance characteristics developed in the T&O metric are widely accepted today, and I believe we can credibly argue that the results are improved designs.

Soundminded (and I believe Ken, also) would observe that fundamental paradigm is wrong, even though we may be doing a better job with it. However, ask SM if his approach isn't also room-independent.

Clearly, there are exceptions.... :(

Edit: Here, max dispersion for $12; get busy and discover the answers:

How about model numbers are where to buy instead of just teasing us?

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You guys have been busy overnight!

Speakers disappearing can be simply a matter of total directivity. I tend to like a speaker with a more focused soundfield. In crossover design better summing of drivers always lends the system a more focused sound. I even recall a system with a slight flare to the tweeter mounting and the grille continued that flare. It gave a very focused sound. I liked it but a colleague thought it was too direct. "Close your eyes and you always know where the speaker is."

This is true, there is an inherent compromise between directness or focus and diffusion and spaciousness. Once you define the number of channels you have to pick your poison on that continuum. John Crabbe gave a famous review of the Bose 901 where he said they gave a nice spaciousness to the orchestra, but when the piano came in it was 20 ft wide. Even mono material had the same width. With headphones on, flip between mono and stereo. The difference is always huge. With different speakers, or different positions in the room, do the same test. If it is hard to tell the difference between mono and stereo you are leaning towards the spaciousness end of things.

The only answer is to have more channels and then use more directional speakers or a deader room. (Come comrades, let us sing...)

I think the "every reflection has to have the same spectrum" notion is an ideal not proven.

I agree with most of what you say here David.

"The only answer is to have more channels and then use more directional speakers or a deader room. (Come comrades, let us sing...)"

Wonder what you think of Ken's Magic speaker; I heard it years ago shortly after it came out.

"I think the "every reflection has to have the same spectrum" notion is an ideal not proven."

I agree completely.

I do remember the comments on the 901.

I don't believe that the disappearing speaker is mainly directivity.

I do agree with the conclusion, probably based on British designs early on, then later confirmed by the NRC and others that smooth

midrange response is key but I think that there are also psychoacoustic effects.

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This is fun stuff, irresistible to speakergeeks.

We each come to this subject with a frame of reference, and conventional wisdom tells us that an ideal loudspeaker is an unattainable objective:

1) Every room is different, and

2) Everyone hears differently.

Toole, however, teaches us to parse speaker, room, and listener, and to analyze them each as independent variables. With this insight, it becomes readily apparent that the task may not be so impossible to accomplish as we first believed.

This simple exercise in clarity of thought also illuminates a stunning proposition, namely, that those characteristics of loudspeakers which confer room independence and excellence of performance might well be exploitable in this quest:

"Toole, however, teaches us to parse speaker, room, and listener, and to analyze them each as independent variables. With this insight, it becomes readily apparent that the task may not be so impossible to accomplish as we first believed."

The reason that I asked previously about your experience or engineering background is that breaking a problem down is fundamental, however what makes a good engineer is one who keeps in mind that the partial view is only an approximation of the real problem and he/she also keeps in mind how the pieces really interact. You should take a look at power amplifier design and how we analyze them, or RF design - significant approximations are made in the process.

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The mechanisms are different above and below the transition frequency. The fact that we can't "hear through" what the room does to longer-wavelength low frequencies is not evidence that this does not occur, comprehensively, even, at higher ones.

This one's tough, and it's the stuff of contention whenever subjectivity enters the picture. Are our capacitors undergoing "break-in," or are we just getting used to them? For every party that prefers speaker A to speaker B, there's a B-lover who'll tell us A sounds like crap, which is why only A/B testing under identical conditions provides any hope of subjectively discerning the difference, and even then, it must be independent, blind, and statistical. In the end, the preference differential may relate more to meaning than substance.... :P

My point was that previously you made the flat out claim that the room doesn't matter. Now you are saying that it does matter at LF.

No capacitors do not beak in, more likely your ear-brain is adapting.

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My point was that previously you made the flat out claim that the room doesn't matter. Now you are saying that it does matter at LF.

Never said it doesn't matter, I don't believe.

It's "fundamental." The room is in control below a transition frequency that varies with room size. Above that frequency, the speaker is in control, and we can work it. It's a transition "zone," actually, with elements of both being operative therein.

********

http://www.jblproservice.com/pdf/AE%20Seri...els/AC16-WH.pdf

http://www.jblproservice.com/forms/parts_order1.html

The waveguides are $6 apiece. The constant-directivity pattern control is exemplary. I've posted about it at least a half-dozen times here in The Kitchen, as recently as the last two weeks, as I recall. You'll also need drivers and filters....

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My experience has not been like that at all. If I walk into a speaker demo and my first impression is that the sound is either good or bad, that never changes on a return trip. I do find that I become better able to ignore differences between different "good" speakers, and that could be adaptation, but I've never revised an initial bad impression on a subsequent hearing.

But doesn't that first exposure give the strongest impression? That is the value of A/B switching, that the transition from one sound to the next give the most obvious contrast. Sure, really bad is really bad, but if differences are minor then the moment of switchover will show it best.

There was a great Stereophile review a couple of years back (can't remember what speaker) where the reviewer tells how shrill the speaker was when he first got it. "Obviously needs some break in." So he put music on it in a side room. Every day or so he walked by and had a quick listen. Over time the "break in" worked. the speaker sounded better and better until he reviewed them and gave them back. Then he was amazed at how dull his old speakers, that he went back to, had become!

This is classic accomodation. He got used to a shrill sound until he thought it was right and then other speakers sounded dull. I've also noticed it at wine tastings where the first sip of a new wine is amazing, by the third sip you can't remember how it is different than the previous wine. Ditto with dark green sunglasses: take them off and the world looks oddly pink.

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Wonder what you think of Ken's Magic speaker; I heard it years ago shortly after it came out.

I think it was a clever (grounded in good science) attempt to break the "directional for focus, dispersive for spaciousness" compromise mentioned above. More directional than anything else we've talked about, with stacked arrays in foam lined recesses, yet it put more lateral sound into the room- but only after appropriate time delay.. It should have fooled the ear into thinking you were in a larger room since there would be strong lateral reflections but at a time delay apropriate to a space with wider dimensions.

But I've never heard a pair. Hey Ken, what did they sound like?? Did it work? Did you get focus + spaciousness?

David

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Nobody suggested it would be easy.

The performance characteristics developed in the T&O metric are widely accepted today, and I believe we can credibly argue that the results are improved designs.

Soundminded (and I believe Ken, also) would observe that fundamental paradigm is wrong, even though we may be doing a better job with it. However, ask SM if his approach isn't also room-independent.

Clearly, there are exceptions.... :P

Edit: Here, max dispersion for $12; get busy and discover the answers:

Thanks for the edit Z, but not to worry, my review of an E-waved KLH 17 will appear here at CSP in the next few months. Remember the ewave boards I ordered from you?

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This is classic accomodation. He got used to a shrill sound until he thought it was right and then other speakers sounded dull. I've also noticed it at wine tastings where the first sip of a new wine is amazing, by the third sip you can't remember how it is different than the previous wine. Ditto with dark green sunglasses: take them off and the world looks oddly pink.

Perhaps it just takes longer for that to happen to me than I have ever been willing to spend in a speaker demo.

Or maybe it is just that it is in my nature to never let go of a perceived fault, and to actively look or listen for it once I have perceived it. When I bought my first house I had the oak floors refinished, and when I accidentally dented the newly-finished wood moving in my furniture, the fellow who had done the floor for me advised against trying to repair it because the repair would be as noticeable as the dent and said that after a while I would forget it was there. I lived in that house for 14 years, and there was never a day when I didn't look down at that floor and immediately notice that dent (I ended up buying a rug for that area and covering it). I probably should have consumed more wine or worn tinted glasses.

When it comes to choosing between two pieces of audio gear, I find that when the differences between them are small enough to require A/B testing to discern, my best course of action is to buy the least expensive one and get the hell out of the store with it rather than do any more listening that may ruin it for me forever. :P

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"QUOTE (speaker dave @ Apr 29 2010, 04:01 AM) *

This is classic accommodation. He got used to a shrill sound until he thought it was right and then other speakers sounded dull. I've also noticed it at wine tastings where the first sip of a new wine is amazing, by the third sip you can't remember how it is different than the previous wine. Ditto with dark green sunglasses: take them off and the world looks oddly pink."

I remember I worked with a fellow who used to work at WGBH, an NPR station here in Boston. They used to use Allison:Fours as monitors throughout the station, but later switched to a Klipsch bookshelf model. The Allison and Klipsch could not possibly have had more different tonal signatures, and at first, my co-worker recalled, he hated the Klipsches.

But within a short time, they became very 'normal'-sounding, and he didn't give them a second thought.

The interesting thing is that there is a continuous window of acceptability regarding such things like tonal balance, directivity, etc, and it's difficult to quantify where the absolute long-term "lines in the sand" occur.

Steve F.

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"QUOTE (speaker dave @ Apr 29 2010, 04:01 AM) *

....................

But within a short time, they became very 'normal'-sounding, and he didn't give them a second thought.

The interesting thing is that there is a continuous window of acceptability regarding such things like tonal balance, directivity, etc, and it's difficult to quantify where the absolute long-term "lines in the sand" occur.

Steve F.

Oh, I totally agree and add that the 'lines in the sand' will vary based on human variability and listening tastes.

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