Dave
I completely agree on these points:
1) sliding window for perception
2) no rigourous studying showing an ideal power response
but I would be cautious on these points
1) that any auditorium "rules of thumb" have any use in a small room
2) that Floyd's ranking says anything about the ideal power response (it may be other factors that caused a good or poor ranking)
3) that Bech's work says anything about the ideal power response (that a floor bounce IS within the window and that other reflections are not)
Finally - that the "power response is primarily useful for revealing resonances" clearly implies that power response is an audible factor or this would not be true.
Most of your arguments point to an attempt to correlate power response to existing data, not to what an ideal power response is. The ideal could be quite different than "typical".
Perhaps there is a slight difference in our points of view because I don't generally look at power response, but more the DI(f) - the two are very closely related however. To me the DI needs to be smooth, fairly high (directivity is a good thing in a small room) and it should dip slowing with frequency on the listening axis. The best speakers that I have heard fit this criteria. And I don't think that its any coincidence that it is quite similar to Toole and Olive most recent recommendations.
So to say that "power response" is not a factor does not, to me, seem correct. To be unclear on how strongly it is weighted in sound quality judgements is most certainly true.
I completely agree on these points:
1) sliding window for perception
2) no rigourous studying showing an ideal power response
but I would be cautious on these points
1) that any auditorium "rules of thumb" have any use in a small room
2) that Floyd's ranking says anything about the ideal power response (it may be other factors that caused a good or poor ranking)
3) that Bech's work says anything about the ideal power response (that a floor bounce IS within the window and that other reflections are not)
Finally - that the "power response is primarily useful for revealing resonances" clearly implies that power response is an audible factor or this would not be true.
Most of your arguments point to an attempt to correlate power response to existing data, not to what an ideal power response is. The ideal could be quite different than "typical".
Perhaps there is a slight difference in our points of view because I don't generally look at power response, but more the DI(f) - the two are very closely related however. To me the DI needs to be smooth, fairly high (directivity is a good thing in a small room) and it should dip slowing with frequency on the listening axis. The best speakers that I have heard fit this criteria. And I don't think that its any coincidence that it is quite similar to Toole and Olive most recent recommendations.
So to say that "power response" is not a factor does not, to me, seem correct. To be unclear on how strongly it is weighted in sound quality judgements is most certainly true.
Which part?
One way to get a loudspeaker to work well in a wide variety of rooms is this:
1. Start out with good first-arrival sound and well-controlled directivity/smooth off-axis response. This way the room's contribution will be timbrally supporting the first-arrival sound.
2. Have some means of adjusting or adapting the bass section to different room acoustic situations at low frequencies.
3. Have some means of adjusting the relative balance of the upper treble for different degrees of "liveness".
The whole point of paying attention to the off axis/reverberant field response is to take into account how the speaker and room interact within the context of how our ears processes sound. It's not a focus on mathematical perfection; it's a focus on that which matters perceptually, and is often underappreciated and overlooked.
Duke
Speaker Dave, thanks for your reply.
It's on a lot of people's lists!
The 4430 was a turning point, in my opinion anyway. How did you come up with the concept, if you don't mind my asking? Did the 4430 have conceptual predecessors?
Maybe I'm barking up the right tree but for the wrong reason... hey, I've done worse.
Duke
It's on a lot of people's lists!
The 4430 was a turning point, in my opinion anyway. How did you come up with the concept, if you don't mind my asking? Did the 4430 have conceptual predecessors?
Maybe I'm barking up the right tree but for the wrong reason... hey, I've done worse.
Duke
Where there isn't conclusive evidence and where authors say "and on the other hand..." that's conjectural. See Earl's post just ahead which addresses some issues. What I think is conjectural is not important.
For sure, I agree with your final thought about perception being the final issue. Funny, this thread is about speakers and hence rooms and speaker placement in those rooms are the "given" unless the manufacturer or DIYer is wealthy, lives alone, and has no guests or is otherwise an extremist about their audio (which is prolly true around here).
You've started listing the ways adjustment to recordings and rooms can be brought about. Brave of you to put forward some thoughts. These are mostly what is left after the speaker box has been brought to theoretical perfection. That illustrates what I'm talking about.
It is diminishing returns (but fun) to chase down the final perfection of the directivity of a horn. But then the speakers are put in a room and located where they fit. Would it be a better "return on effort" to devote design effort to be able to swivel the horn part(s) of a speaker and/or to develop speaker directivity with more appreciation of the range of rooms? Right now, there seems to be an impulse to design speaker directivity for some hypothetical average (or worse, some ideal room) and to debate what is best for that room. That's about about as wise as designing a car for two adults plus 2.1 kids and any other group would be out of luck. As I said, the room is the given and the speaker, as far as this thread is concerned, is the accommodating element that gets design attention.
So, your good room/recording accommodation ideas can be accomplished either electrically or acoustically but not within a speaker necessarily. If were in the speaker business, I'd have swiveling tweeters and a cheap laser pointer inside the swivel mechanism to help orient them in a room.
Now there's a patent idea!
Footnote: Somebody (like Cosmic Speaker Corp) have data on listening rooms? It is a blunder to design for the average instead of the range.
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Or have a phased array of micro transducers, comprising a self calibrating
mechanism to adjust frequency dependent directivity according to
the room in which it is placed.
Adding sweet options for manipulating the calculated default setting by
the customer.
I think that is the point: if hearing relies on time windowing to define perceived frequency balance, then sound can arrive after that time window and have little or no effect. That makes it hard to pin down an ideal power response.
Floyd makes this distinction several times and I've never been comfortable with it: The implication is that uneven response due to reflections, interference, etc. is okay because it changes when you move your observation point. Resonances are generally there at every angle and are therefore bad. Based on that belief, he finds that anything that remains when a lot of meaurements are averaged is a resonance and undesirable. I don't know if that implies power response is important (the resonances would be in the direct response as well) or if measuring power response is just a good way to find resonances.
True, but is it likely that there is a "better" power response out there that we haven't stumbled across? Certainly, if speakers with uneven power response can rank high in carefully controlled tests, and speakers with better power esponse can be ranked low, then power response isn't a necessary criterian.
But if we agree that flat smooth axial response is a good thing, then DI and power response are inseperable.
I'll concede that power response shouldn't be totally discounted. I generally have this discussion with people that are arguing that flat power or some particular power response is more important than flat and smooth direct response. I think that neither of us are in that camp.
I'm comfortable with the Lipshitz and Vanderkooy conclusions: that flat power response at the expense of flat axial response is bad, that holes in the power response are generally unheard, that peaks in the power response can be heard, and that increasing and flattening the power response (without degrading the axial response) tends to make a system sound brighter.
Finally, although I would tend to agree that moderately high directivity and a reduction in the contribution of the room is a good thing (and becomes an even better thing as you add more channels), there are a lot of listeners that like a more diffuse presentation.
This is a very interesting discussion!
David
I can't claim to have conceived of the unit. In fact there were some rough prototypes around when I joined JBL. I was priveledged to design the network, finish the system, and write the AES paper.
Don Keele had joined the company a couple of years prior and worked out a new "recipe" for CD horns that got around his patents at EV. He was working up a number of horn designs, primarily for large theater use with the usual 90 x 40, 60 x 40, etc. patterns. Since the contours were scalable he worked up the smaller 100 x 100 horn and it was probably obvious to all that it would be great for a studio monitor.
At the same time UREI was stealing some business and making 2 way monitors popular again, so this was a natural answer to that.
David
If this is what we are agreeing to then I'm absolutely on board.
Kind of rare here often times. Few people quote any real data, its usually "I heard this and it means this". Stops a discussion cold because its so blind to reality. Or they saw "you should do this" and wonder why you don't drop everything and do it. Or another favorite "There is no conclusive proof of that." as if anything in audio is ever that clear cut.
I agree with that rules of thumb for adaption of a certain speaker
to different listening rooms. You are briefly summarizing,
what is needed in the end and it meets my experience well.
Kind Regards
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How so?
I prefer direct and reverberant because they reveal the mechanism for why they're early and late.
Seems we are arriving at a very serious and deep debate, with good arguments on all sides. But there seems to be a pretty obvious basic issue that needs to be recognized: the room.
Would anybody disagree with the obvious statement that some speakers sound better in some rooms and placements and other speakers in others?
So it seems a trivial implication of that, that total power and directivity have to be matched to the environment... unless you are working with a speaker which has adjustments to accommodate the acoustics (which all do to a tiny extent, but few do to much extent).
So it seems to me that a speaker manufacturer can claim no more than, "If your room is so-and-so, my speaker will sound great." But if the room is pretty dead, there is only ONE chair in it and that is plunk at the sweet spot, you are free to place 3 sub-woofers strategically, and so on, you want a different speaker.
Just chasing your own tail to argue about which speaker is the perfect speaker given the range of imperfect rooms and our lack of information about them.
Would anybody disagree with the obvious statement that some speakers sound better in some rooms and placements and other speakers in others?
So it seems a trivial implication of that, that total power and directivity have to be matched to the environment... unless you are working with a speaker which has adjustments to accommodate the acoustics (which all do to a tiny extent, but few do to much extent).
So it seems to me that a speaker manufacturer can claim no more than, "If your room is so-and-so, my speaker will sound great." But if the room is pretty dead, there is only ONE chair in it and that is plunk at the sweet spot, you are free to place 3 sub-woofers strategically, and so on, you want a different speaker.
Just chasing your own tail to argue about which speaker is the perfect speaker given the range of imperfect rooms and our lack of information about them.
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A prime intent of waveguide designs is to render the room "manageable" via controlled directivity. Many other approaches function at the mercy of the room, as you suggest, in varying degree. There is an entire industry devoted to room treatments and their deployment for performing the requisite "adjustments."
Toole provides insight into the utility of analyzing the characteristics of loudspeaker and room independently, then, with this knowledge, optimally combining them for a desired result. The first questions are always "What kind of music do you like," and "Describe your listening space." Ideally, both would be moot....
Toole provides insight into the utility of analyzing the characteristics of loudspeaker and room independently, then, with this knowledge, optimally combining them for a desired result. The first questions are always "What kind of music do you like," and "Describe your listening space." Ideally, both would be moot....
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That is a remarkable claim.
Just for speculative purposes and overlooking - just for the sake of inquiry - your assertion that these speakers are aiming for complete perfection vis a vis room acoustics, what would you say is the better kind of room/placement for controlled directivity and the worser?
(That may all be very obvious to most readers, but I am kind of a curious newbie without time to read the whole thread, thank you.)
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Thanks. Perhaps I didn't give it the depth of attention it deserves when I read it the first time.
Despite the quite compelling first impression that Earl's paper leaves, I am sure not many readers would still write it off as just venal advertizing bumpf if they truly read it carefully.
I appreciate the link. But pointing your finger towards a long debate-paper as if any fool would suddenly have "the scales drop from their eyes" after exposure to those enduring truths, is not the same as simply offering your opinion to help me. But if pointing your finger toward stuff on a commercial website is the best you can do....
Are you you saying the readers are not intelligent enough to follow the argument? Or, are you saying the argument is not legitimate because the writer manufactures speakers? Or, are you saying the argument is not clean because the writer thinks his treatment of the small rooms' problems is well served by the speakers he manufactures?
So what's your problem? The argument has to stand on it's own, regardless of who makes the speakers
You say you don't have time to read this whole thread where these things have discussed in a very energetic fashion. Other folks time is worth something also: Perhaps Zilch gave you the reference because it contains the argument you're asking for without having to spend a LOT of HIS time writing it.
