Sean Olive on Predicting Loudspeaker Sound Quality and Listener Preference

[hardisj]

For those who might be interested, @Sean Olive was gracious enough to join me for an informal live stream last night where he discussed his research into loudspeaker preference prediction. Some real good nuggets of info in here. I also gave an ASR shoutout and specifically to @pierre for his work in compiling the data and generating scores from mine and Amir’s data (specifically time stamp 48:20).

I gotta say, this was my favorite chat so far. I can’t thank Sean enough for coming on and giving some more context and also taking time to answer viewer questions at the end. A couple key ones:
@1:03:10 - someone asked specifically about directivity wrt wide vs narrow dispersion. I immediately thought of @napilopez and his opinion on this.
@1:05:50 - significance of an Olive score of 5.0 and 6.0

If you want them, you can find the link to his slides in my video description on YouTube.

Also, here is a link to Pierre’s site for those who may not be aware of it:

A collection of loudspeakers measurements

 

[Zensō]

I enjoyed the chat. I was disappointed though, that headphones weren’t discussed. Perhaps for another session sometime?

 

[abdo123]

That Revel Salon in the background gave me a lot of big dick energy.

 

[hardisj]

I enjoyed the chat. I was disappointed though, that headphones weren’t discussed. Perhaps for another session sometime?

He discussed that with Gene @ Audioholics last Friday. We very briefly touched on that but here is the link:

 

[Zensō]

He discussed that with Gene @ Audioholics last Friday. We very briefly touched on that but here is the link:

Thank you!

 

[Zensō]

For those who might be interested, @Sean Olive was gracious enough to join me for an informal live stream last night where he discussed his research into loudspeaker preference prediction. Some real good nuggets of info in here. I also gave an ASR shoutout and specifically to @pierre for his work in compiling the data and generating scores from mine and Amir’s data (specifically time stamp 48:20).

I gotta say, this was my favorite chat so far. I can’t thank Sean enough for coming on and giving some more context and also taking time to answer viewer questions at the end. A couple key ones:
@1:03:10 - someone asked specifically about directivity wrt wide vs narrow dispersion. I immediately thought of @napilopez and his opinion on this.
@1:05:50 - significance of an Olive score of 5.0 and 6.0

If you want them, you can find the link to his slides in my video description on YouTube.

Also, here is a link to Pierre’s site for those who may not be aware of it:

A collection of loudspeakers measurements

@hardisj BTW, I’m seeing this error:

 

[Matias]

Pure gold. Thanks for the interview.

 

[hardisj]

@hardisj BTW, I’m seeing this error:

View attachment 155248

Fixed. Thanks for the heads up. YouTube sometimes defaults to not allowing embedding.

 

[MCH]

I also own an akg k371 like mr. Olive does, and like mr. Olive I also struggle to wear them straight. Second video of him showing the same.

I need to say that even when worn wrong they are super comfortable and i dont realise until my wife makes fun of how i look

What a great headphone and what a stupid adjustment system, i hope Sean Olive has the influence and will to get it improved in future models.

 

[Geert]

Great interview. And a handy reference for everyone that's still convinced that all research on speaker preference is based on Toole and a few friends messing around with a couple of speakers in his garage.

 

[napilopez]

Great stuff @hardisj. Don't know if you saw my comment but indeed I thought the bit on directivity width was interesting! It was nice to see some validation that I wasn't crazy for preferring wider directivity speaker in smaller/narrower rooms rather than larger ones, against common advice (and even my own initial intuition).

(Although it also bears mentioning that there are no real definitions for what constitutes 'narrow' and what constitutes wide. Based on the current market, I'd consider something like a Genelec or Klipsch 'narrow' and most revels and cone/dome speakers 'wide,' but for all i know he could mean giant horns for narrow.)

It was also nice to see Dr Olive. talk a bit about the shortcomings of these papers and how they could be improved, even just using the original data. That'd be very interesting to see.

 

[abdo123]

Great stuff @hardisj. Don't know if you saw my comment but indeed I thought the bit on directivity width was interesting! It was nice to see some validation that I wasn't crazy for preferring wider directivity speaker in smaller/narrower rooms rather than larger ones, against common advice (and even my own initial intuition).

(Although it also bears mentioning that there are no real definitions for what constitutes 'narrow' and what constitutes wide. Based on the current market, I'd consider something like a Genelec or Klipsch 'narrow' and most revels and cone/dome speakers 'wide,' but for all i know he could mean giant horns for narrow.)

It was also nice to see Dr Olive. talk a bit about the shortcomings of these papers and how they could be improved, even just using the original data. That'd be very interesting to see.

I’m pretty sure the argument for narrow directivity in small rooms is in the context of accuracy not enjoyment.

 

[napilopez]

I’m pretty sure the argument for narrow directivity in small rooms is in the context of accuracy not enjoyment.

This is usually the same thing, also per toole/olive research

Edit: By the above, I'm interpreting 'accuracy' as 'perceived realism.'

But in any case, I think I've usually seen the recommendation for narrower speakers in narrower rooms as kind of a blanket factoid recommendation.

 

[ferrellms]

I’m pretty sure the argument for narrow directivity in small rooms is in the context of accuracy not enjoyment.

Yes, why is listener preference more important than accuracy? How many of these listeners have actually heard an accurate system? Until really modern loudspeakers and proper rooms are used in comparison, all this listener preference stuff is not so useful.

By proper speakers and rooms, I mean - high ratio of direct to reflected sound, few early (<20ms) reflections, time correct (phase linear), digitally EQed carefully for the listening position, diffuse reverberation.

I would wager that this environment is not available in the "listener preference" tests. And why would it be? Harman makes products for the home entertainment market, not products that fit the specifications for true accuracy, as do Genelec (along with proper room treatment), Dutch&Dutch, and Kii. Much of this technology did not even exist when Toole was hacking around in the anechoic chamber.

Certainly, the JBL line contains some superb pro gear, but is this listened to in the proper environment (room treatment) for true accuracy?

 

[richard12511]

@preload Dr. Olive discusses the 13 speaker test with .99 correlation that I was talking about and looking for(but couldn't find) in the other thread.

At 14m28s he talks about the differences between the 13 speaker test(with .99 correlation) and the 70 speaker test(with .86 correlation). The main difference being that the 13 speaker test was more carefully controlled, whereas the larger test had speakers of all different sizes with large differences in bass extension.

At 45m36 you can see the r value and predicted vs measured preference graph of the 13 speaker test.

14m28s
45m36s

I was pretty sure I was remembering what I read correctly. I just couldn't remember where it was that I read it, and couldn't figure out what to google in order to find the study.

 

[richard12511]

Great stuff @hardisj. Don't know if you saw my comment but indeed I thought the bit on directivity width was interesting! It was nice to see some validation that I wasn't crazy for preferring wider directivity speaker in smaller/narrower rooms rather than larger ones, against common advice (and even my own initial intuition).

I wish I could find where it was on AVS forums where Dr. Toole also talks about the importance of wider dispersion. It's somewhere in one of those 2-3 hundred page forum threads on AVS. I read through the M2 vs Salon2 shootout thread entirely again(looking for it specifically), and it wasn't in there.

For the quote I'm thinking of, he basically lists wider dispersion as either the second or third(memory is leaning more towards second) most important factor for predicting listener preference. He also uses that as the reason why he predicted the the Salon2 to beat the M2 prior to the shootout.

That said, if there is an optimal(meaning most preferred on average) dispersion width, I have a hunch that it's going to depend on the number of channels. I'm thinking optimal dispersion width will be much wider in mono than it will be for 11 channels. If that's true, you almost have to test with the configuration you're trying to predict for, at least with speakers that excellent otherwise. That's problematic though, given how much less discriminating we are as the number of channels increases. I guess you'd just need a much larger sample size? Otherwise, you risk getting an answer that doesn't match for the configuration you're trying to predict. Does that make sense?: Three speakers - A, B, C - that are equally flat on-axis, equally smooth off(lack of resonances), but with different dispersion widths. Speaker A (160°)wins the mono test, B(110°) wins the stereo test, and C(80°) wins the 11 channel test.

Last paragraph is pure speculation on my part, but I'd love to be proven wrong or right with further research. First hard part is finding speakers that have equally flat direct sound and lack of resonances, but very different dispersion widths. Perhaps something like the Beolab90? Second hard part is dealing with the fact that we get much less accurate with our ratings as the number of channels increase. Maybe with a large enough sample size, the wisdom of crowds might prevail?

 

[napilopez]

Yes, why is listener preference more important than accuracy? How many of these listeners have actually heard an accurate system? Until really modern loudspeakers and proper rooms are used in comparison, all this listener preference stuff is not so useful.

By proper speakers and rooms, I mean - high ratio of direct to reflected sound, few early (<20ms) reflections, time correct (phase linear), digitally EQed carefully for the listening position, diffuse reverberation.

I would wager that this environment is not available in the "listener preference" tests. And why would it be? Harman makes products for the home entertainment market, not products that fit the specifications for true accuracy, as do Genelec (along with proper room treatment), Dutch&Dutch, and Kii. Much of this technology did not even exist when Toole was hacking around in the anechoic chamber.

Certainly, the JBL line contains some superb pro gear, but is this listened to in the proper environment (room treatment) for true accuracy?

Because there is no such thing as true 'accuracy' in traditional stereo speakers. You just can't fully recreate a 3D soundfield with two speakers, and unless your setup is identica to the recording engineer's, you won't replicate that sound either. The best we can do is a convincing illusion. And in listening tests, the speakers that are the most preferred are the ones that create the greatest impression of realism and accuracy.

The D&D's designer has explicitly said the 8C was inspired by the ideas in Dr Toole's book. Genelec and Kii speakers follow the same principles too. In fact, all the best studio monitors are doing precisely what is suggested by the Harman Listening tests: flattish on-axis and smoothish directivity. The principles for perceived accuracy are mostly the same at home and in the studio. Harman also has a whole pro line of studio speakers which are not at all intended for the home market. So I'm not sure your reasoning holds water.

The only difference is in some studio situations people prefer to have lesser room reflections so they're only listening to the sound of the speakers. But take that to the extreme and you've basically just got an anechoic chamber or headphones.

 

[richard12511]

Yes, why is listener preference more important than accuracy?

Might be a matter of use case. As someone listening recreationally, purely for pleasure, I'm looking for what sounds best, not what is most accurate. I do tend to gravitate towards accurate speakers, but only because I believe that's what gives me the best chance at maximizing sonic pleasure.

If I was mixing music, I might have a different stance, or maybe not.

 

[PierreV]

@preload
At 14m28s he talks about the differences between the 13 speaker test(with .99 correlation) and the 70 speaker test(with .86 correlation). The main difference being that the 13 speaker test was more carefully controlled, whereas the larger test had speakers of all different sizes with large differences in bass extension.

While Dr Olive makes good points about the speakers being different and the controls not being equivalent between studies, a .99 correlation on a sample size of 13, with 5 parameters screams overfitting.

Overfitting Regression Models: Problems, Detection, and Avoidance

Overfitting regression models produces misleading coefficients, R-squared, and p-values. Learn how to detect and avoid overfit models.

statisticsbyjim.com

 

[More Dynamics Please]

I wish I could find where it was on AVS forums where Dr. Toole also talks about the importance of wider dispersion.

Try going to the AVS forum's advanced search and enter Floyd Toole under Posted by and "wide dispersion" (in quotation marks) under Keywords. That will give you 24 posts in which Dr. Toole mentions the term wide dispersion. The post you're looking for should be one of those 24.