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Why don't all speaker manufacturers design for flat on-axis and smooth off-axis?

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#81
Dr, Toole mentioned an $1800 speaker that had great measurements, does anyone know what speaker that was?

Is the a database of the spinorama measurements?
 

amirm

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#82

MattHooper

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#83
What then, are the reasons so many speaker manufacturers seem to deviate from this approach?

The cynical answer - and probably truthful, in some cases - is that it's just aesthetics and marketing.
Yes that's the most cynical take on it, and as you say may be true in some cases. Alternatively, manufacturers may be making the type of speakers they like. A large portion of, for instance, high-end speaker manufacturers started out as enthusiasts building just the type of speakers they wanted to hear, and from that experience honing a design over time that does what they specifically want it to do. That's how you get the variety of horn designs, planar designs, dynamic speaker designs, omnis etc. People are making them because they are manufacturing them for how they want them to sound, and on principles and criteria they have come to hold to over time.



These days, there's certainly no reason why a loudspeakers shouldn't be flat unless deliberately designed not to be. I really do wonder what's gone on in the mind of designers of dreadful stuff like Zu or Boenicke.

S
How about a reason like: The designers are making the type of speakers they like in terms of certain sonic characteristics they value, and then they have a customer base because other people like how those speakers sound.

I've read tons of reports from Zu owners (and a few Boenicke) who are just giddy over the sound of their speakers. The think they sound great, with the music they like to listen to. That's reason enough. Why doesn't, for instance, a John Devore design speakers to sound how you want it to sound? Because he's trying to please himself and customers who like what he likes.

I recently drove my son's car to get something and as I left the door he yelled "you might find the sound a bit bassy!"
I tried playing even one of my podcasts on the car's stereo system and it sounded horrendous. I looked at the EQ settings and it was the worst "smile" settings I've ever seen: treble up, midrange turned completely down, bass all the way up.

But...these are the settings that produce the sound my son prefers with the music he tends to listen to: Rap. (And rap tends to be produced this way to begin with: high hat tipped up frequencies, voices squashed to tiny autotuned robots, and BIG BASS).

Some people find a speaker tuned a certain way actually appeals to them for the music they listen to. You could say "buy a neutral speaker and play with EQ." But most people don't want to do that. Few people want to bother equing from one song to the next to get "just the right" eq.
Well...then they could just find a general setting that works for most of what they listen to. But then...they can do essentially the same thing by buying a speaker voiced the way they like for most music, and skip bothering with adding an EQ.

Do people's opinions tend to converge in bind testing speakers? Looks like it given the research often cited. But in the usual sighted way people buy speakers, it seems people find great satisfaction in much wider variety of speakers. Due in some cases to extra-auditory influences? Sure could be, but the end result is an experience in any case, with someone group playing their music on say, a Zu speaker, and having an experience of "wow this sounds amazing!." Hence people find satisfaction - to their perception, sonic bliss - with quite different sounding speakers.


The #1 thing in a successful speaker business is marketing. Unfortunately consumer awareness of Dr. Toole research is close to zero. I am actually pleasantly surprised how much our members know about it.
I know about it.

Yet I found I have liked both speakers that conform more closely to the HK-school of design and speakers that depart from it.
So consumer awareness may not be enough to produce much greater conformity of choice. People are messy like that :)
 

BillG

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#84
But...these are the settings that produce the sound my son prefers with the music he tends to listen to: Rap. (And rap tends to be produced this way to begin with: high hat tipped up frequencies, voices squashed to tiny autotuned robots, and BIG BASS).
That's not Rap in the classic sense of the genre, but rather a subgenre called Trap... ;)
 

Blumlein 88

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#87
I agree with this. The most important thing, I think, is actually to get other research groups to replicate the experiments, and see if they come to the same results. I do research for a living, albeit in a field which has nothing to do with audio at all. And in the fields in which I work or which I follow closely, you can't take findings for granted unless they are replicated and corroborated by other research groups. There is a reason people speak about a "replication crisis" in science... scientists often get small things wrong, even though they act in good faith, and it's difficult to know whether one has actually measured what one thinks one has measured. One of the most important things is actually to have different research groups working on similar questions, as this makes it more likely that mistakes or limitations are discovered.

What troubles me slightly with lifting up the Harman research to the status of an undisputed audio gospel is that this is basically one research group, who also had commercial interests in what they were/are doing. I don't mean to disparage their work at all - Toole, Olive and Welti and the others have done an immense service to the audio community by putting so much of their work out in the public domain. Really. The problem is not that they have been doing this work - quite on the contrary - it's rather that so few others have bothered to replicate or challenge the studies! "Psychoacoustic loudspeaker science" is basically such a small and underfunded field... and unfortunately it's probably going to stay that way, given that high-end audio seems to be destined for the same end as the dinosaurs.

But take the issue of the dipole speaker, for example. In Harman studies, no good. In one of Søren Bech's studies, however, the dipole received the highest rating given a particular placement, and the worst rating, given a different placement.
View attachment 29560 View attachment 29560
Source: https://www.researchgate.net/public..._sound_quality_-_a_review_of_existing_studies

This is just an example. Now it would be relatively stupid to claim that flat frequency response on-axis and smooth response off-axis is bad. Nobody thinks that. The interesting devil lies in all the details in speaker design. How much weight should on-axis flatness be given, relative to behavior off-axis? There is a genuine trade-off here - equalizing the speaker to improve off-axis may make it slightly worse on-axis. Waveguides or horns may improve directivity patterns, but how about those HOMs? And what about things like transient response, dynamics etc? (here's a paper I read some time ago on that: https://eprints.soton.ac.uk/426110/ )

I don't mean to spread FUD here. The Harman way of doing speakers is obviously a very good and valid way of doing speakers. In my sighted listening I usually tend to like speakers that are designed according to the Harman philosophy. But my sighted listening has also told me that I can like equally well speakers that are designed according to other philosophies (prioritizing low distorsion, phase coherencey and "flat enough" response on-axis, for example). Until other research groups start replicating Harman's experiments, I'll probably not become convinced that flat response on-axis and smooth response off-axis are the only things that matter.
In regard to panel speakers, I think people forget the Quad ESL63 was segmented and effectively a quasi point source. Though expensive, one could take that next step and using more segments create a more true point source or line source and with DSP on the segment inputs you could create directionality as you wished within reason. You wouldn't have speakers that beam mostly and then at some low frequency become more dipolar as most panel speakers are. So it might be possible to make a panel that also follows a design goal of one similar to comparable to what Harman does.

I've also thought it would be possible to create a backstop for moderate sized panels that are shaped to splay reflections from the rear at frequencies that beam toward the front to fill in and give a less beamy frontal presentation. Something like Klipsch did with corner horns. Probably need the panel to not go too deep and some research in to how this works over a couple octaves that transition from beaming to not beaming.
 

jhaider

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#88
B&Ws are a fixture in Harman studies. It is often disguised as speaker "B." Indeed it was among the pool of speakers when I participated in the blind tests:

View attachment 29538

It is the one to the left.

I scored the JBL the highest (on the right), then B&W and finally Martin Logan in the center.
In that group I'm not too surprised, though the new MartinLogans sound with digitally corrected (ARC) cardioid bass sound a lot better than the old ones when calibrated. I suspect those would win in the blind because the bass would be so much cleaner.

A couple years ago the Harman store in NYC had those JBLs and Salon2s in the basement. It was a sighted listen, but I was struck most of all by the difference in soundstage width between them. The Salon2 was much better in that regard.
 

jhaider

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#89
In order to assess the impact of controlled directivity, it would be interesting to have a repeat of the Harman blind test but including speakers design (or should i say marketed) with different chief design approaches and at least share very good on-axis response, for example:

Controlled directivity as chief design trait
- Revel Salon 2
- KEF reference 5 (uni drivers)
Add NHT:
1563333744294.png


1563333785803.png


and Bryston:
1563333833262.png

1563333808974.png



I would love to do Spinoramas. I took full Spinorama-style horizontal and vertical measurements for an upcoming speaker review in case I could figure out how to generate a Spinorama from them. Alas, I'm not computer-adept enough to derive and plot early reflections, sound power, and the two DI's. I had an email exchange with somebody else who does Spinoramas in Excel, and it was clear it was above my capabilities when he mentioned converting dB values to scalars and then converting them again.
 

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napilopez

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#91
Spinoramas are certainly a clean and concise way of representing a speaker, but I do personally prefer being able to see the specific responses at different angles a-la soundstage network's NRC measurements.

Also, I thought there was a dipole that did perform well in one of these blind tests? I can't remember which though.
 
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#92
In my opinion, the manufacturers of hi-fi loudspeakers are more concentrated with the appearance than the sound quality. To create a speaker with CD (Controlled, Constant Directivity) characteristics, the appearance must be designed in a certain direction.

First, there must be a waveguide around the unit. The wave guide should be carefully designed. Second, the edge of the speaker enclosure should not be too sharp like 90 degrees. Diffraction can occur.

I think these two things have a big impact on speaker design. It is certainly far from the linear modern design which I prefer. Obviously, Dieter Rams or Bauhaus designers will not have good performance if they design speakers. :D

Studio monitors have liberty in that aspect. I think the whole form, including the JBL M2's waveguide in use, is so beautiful. But most people do not think.

Most of the speakers selected in the market are looks good. Speakers are furniture. If consumers have good ears and focus on performance rather than speaker design, the stream will change.
 

Krunok

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#93
In my opinion, the manufacturers of hi-fi loudspeakers are more concentrated with the appearance than the sound quality. To create a speaker with CD (Controlled, Constant Directivity) characteristics, the appearance must be designed in a certain direction.

First, there must be a waveguide around the unit. The wave guide should be carefully designed. Second, the edge of the speaker enclosure should not be too sharp like 90 degrees. Diffraction can occur.

I think these two things have a big impact on speaker design. It is certainly far from the linear modern design which I prefer. Obviously, Dieter Rams or Bauhaus designers will not have good performance if they design speakers. :D

Studio monitors have liberty in that aspect. I think the whole form, including the JBL M2's waveguide in use, is so beautiful. But most people do not think.

Most of the speakers selected in the market are looks good. Speakers are furniture. If consumers have good ears and focus on performance rather than speaker design, the stream will change.
Taste is of course a very personal thing, but these Revel F208 speakers not only have good directivity but also look very nice to me. And to my wife.. :D

F208.jpg
 
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#94
Taste is of course a very personal thing, but these Revel F208 speakers not only have good directivity but also look very nice to me. And to my wife.. :D

View attachment 29584
I agree

I actually heard it when I met Dr. Sean Olive.
He owns both JBL M2 and REVEL ULTIMA SALON 2, But SALON 2 is mainly used because WAF(wife acceptance factor) is higher than M2. :facepalm:
 

617

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#96
Taste is of course a very personal thing, but these Revel F208 speakers not only have good directivity but also look very nice to me. And to my wife.. :D

View attachment 29584

The irony of this research, to me, is that it supports the idea that a very conventional 3 way bass reflex speaker with a smallish midrange and a tweeter in a demi waveguide produces the best viable sound in a living space. You can design a pretty good speaker similar to this one by accident.
 

Krunok

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#97
The irony of this research, to me, is that it supports the idea that a very conventional 3 way bass reflex speaker with a smallish midrange and a tweeter in a demi waveguide produces the best viable sound in a living space. You can design a pretty good speaker similar to this one by accident.
You could, indeed. And I'm pretty sure that happened. But let's not forget that there's some serious technology in those drivers as well.
 

napilopez

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#98
Agreed that design goals likely sometimes compromise sound, but I also think there's enough room to maneuver with varying designs despite some obvious physical attributes being necessary for a given design. Take the Kii Three and Dutch & Dutch 8C; theyre both flattish on axis with cardioid dispersion, but they achieve that pattern in totally different manners, and of course with totally different aesthetics.
 

Krunok

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You guys don't notice the value of DI now - F208 represent a very low DI (directivity index9 but D&D and Kii aim for much higher DI (narrower red area in spinorama).

More data of dispersion here by Princeton 3D lab https://www.princeton.edu/3D3A/Directivity.html
What exactly do you mean? Here is spinorama for F208:

F208 Spin.jpg


Let me also add this for folks less familiar with spinorama:

HARMAN Spin-o-rama Explanation

On-axis Response - This represents the direct sound heard by a single listener sitting on the design axis of the loudspeaker. A flat frequency response is an absolute requirement for all electronic devices. Therefore, it is not surprising that loudspeakers with a flat on-axis frequency response have a higher probability of being preferred in double-blind listening tests.

Listening Window - The well-designed loudspeaker should deliver good sound to a group of listeners -- not just the person sitting on-axis. The listening window is the average frequency response measured for listeners sitting on and slightly off the reference axis of the loudspeaker. Loudspeakers that receive high sound quality ratings in double-blind listening tests tend to have listening windows with a flat frequency response.

First, or Early Reflections -- Most of the sound we hear is reflected in rooms. The second loudest sound (after the direct sound) is the first reflected sound produced from the loudspeaker. Therefore, it is paramount that the sounds radiated by the loudspeaker in the off-axis directions generate early reflections that sound good. The shape of this curve should not differ greatly from the on-axis response curve.

Sound Power Response -This is a measure of the total sound radiated by the loudspeaker without regard to the direction in which it is radiated. The shape should be smooth and slightly downward tilting.

Sound Power and First Reflection Directivity Indices - These directivity indices tell us how the directivity of the loudspeaker changes as a function of frequency. At low frequencies most loudspeakers radiate sound omni-directionally (DI = 0 dB), where wavelengths are long. In forward-firing, 2-way and 3-way loudspeakers, as wavelengths get shorter, frequencies get higher, and more of the sound is radiated towards the front. The goal is to have this trend develop smoothly and gradually.
 
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