Yes. See: https://speakerdata2034.blogspot.com/2019/02/spinorama-cea-2034-2015-ansi-data-format.htmlIs the a database of the spinorama measurements?
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.
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
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.
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...
It's a trap alright ;-)
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 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.
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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.
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:
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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 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)
I realize you're probably trying to make a joke here, but the socioeconomic conditions that gave birth to the subgenre are anything but...
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.
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..
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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.
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..
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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 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