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Sean Olive on Predicting Loudspeaker Sound Quality and Listener Preference

BenB

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...

Ultimately, perhaps we should consider having multiple setups--"horses for courses" and all that, haha.

Young-Ho

One of the things I'd like to see is variable dispersion speakers at a reasonable cost. I think this is within our grasp using some constant directivity drivers in a multi-directional set-up, with potentiometers, or more likely using separate amplification for each direction. I performed a rather flawed proof-of-concept for the idea for very cheap, and found potential in the results. Details here: https://www.audiosciencereview.com/...ctivity-experiment-wall-splasher-2-way.25558/

If a follow-up project that's more true to the concept and less flawed is to take shape, it will have to be a convincing idea to justify the cost. Also, to quote my wife "we don't need another pair of speakers." Still, I do think about how to pull it off from time to time.
 

amirm

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One challenge for us using the scoring is that our objective measurements did not lead to the same scores. It seems our measurements are higher resolution than what was used during the study but that is just a guess. FYI I also bough the Bose speakers that were used in the study. I will see if I can test them.
 

ernestcarl

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

I like to have the ability to quickly switch between the effect of narrow directivity for very “critical” listening and a more spacious sound similar to what you get from wider directivity speakers for added ambience. The way I (and many others) do this is through multichannel upmixing. Careful placement is important… but it is not critical to have the exact same speakers for the surrounds as long as you can match the overall tonal balance close enough — measurements should be compared plus listening tests performed by re-routing or switching channels back and forth — also this is to check that one does not inadvertently make the surrounds stand out too much — with the help of DSP, of course.

Though, the market seems to be focused on stereo as it is simply far easier to set up.
 

ernestcarl

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I'm thinking optimal dispersion width will be much wider in mono than it will be for 11 channels.

That makes sense.

I’m thinking also in a mch listening space with multiple seating, the choice of optimal directivity is dependent in the arrangement. For instance, one might not exactly want certain kinds of “very narrow” directivity surrounds that do not adequately cover the other seats, say, esp. in the mid and HF — though, maybe more so if one has fewer surrounds (e.g. two) instead of many.
 

JRS

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Which is why I was asking @preload originally about it. I wanted to know how much the smaller sample size affected things. He's good with stats, but he didn't really believe me about the .99 correlation thing(understandably so). I'm especially interested in how well the model can predict monopole speaker comparisons where bass extension is of little importance(ie using subs), and I know he's really good at that kinda stuff.

13 samples for 4 variables does seem quite small, but it's important to point out that it's not 13 comparisons, but 13 speakers that are all compared against each other many times with many different combinations.

It may be that the sample size of the first study doesn't need to be as large, since it's much more controlled, both in terms of bass extension and the type of speaker(only monopole(except 1?)). The larger study does bring in a larger sample size, but it also introduces a couple extra really important variables, namely widely different bass extensions and speakers of completely different types(panels, open baffles dipoles, etc.)

While the sample size of the larger study is nice, I have a hunch that it's a mistake to try to come up with a single model to predict preferences for all types of speakers. My hunch is that trying to do so is lowering the correlation, and it might be easier and/or better to try separate models for separate speaker types.
I heard him say that too--that they were all tested against each other which is quite a number of trials-it would be 1 vs 2-13 (12) 2 vs 3-13 (11) 3 vs 4-13 (10) and so forth, i.e. sum of 1-12= 12(13)/2= 78. And that's per listener of course. I believe the points you make are sound, and also what Erin said about listening at different levels seems extremely pertinent. One would think that one would want something of an inverse Fletcher-Munson FR at what he'd say 80dB--in other words exaggerated bass would help. By 90dB things start to get very flat, at 100 very flat. Ultimately, while helpful, this is just scratching the surface of the topic and likely applies more to Joe Bloe than Joe Audioho.
 

JRS

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I like to have the ability to quickly switch between the effect of narrow directivity for very “critical” listening and a more spacious sound similar to what you get from wider directivity speakers for added ambience. The way I (and many others) do this is through multichannel upmixing. Careful placement is important… but it is not critical to have the exact same speakers for the surrounds as long as you can match the overall tonal balance close enough — measurements should be compared plus listening tests performed by re-routing or switching channels back and forth — also this is to check that one does not inadvertently make the surrounds stand out too much — with the help of DSP, of course.

Though, the market seems to be focused on stereo as it is simply far easier to set up.
Perhaps. Just as soon as I save enough money Sanders 10E's a couple of kW of power, and some of that BAACH magic--to me that renders many of these discussions moot. That Doc Chouieri from Princeton may be that guy who turns audio inside out, and the high Q speakers will be all the rage. Link to Part 1 of 3 here:
There is also a thread on this site if you haven't seen it. This may be the ga-ga realism factor we have all been waiting for--and best thing we don't have to buy all our music over again.
 

ernestcarl

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Perhaps. Just as soon as I save enough money Sanders 10E's a couple of kW of power, and some of that BAACH magic--to me that renders many of these discussions moot. That Doc Chouieri from Princeton may be that guy who turns audio inside out, and the high Q speakers will be all the rage. Link to Part 1 of 3 here:
There is also a thread on this site if you haven't seen it. This may be the ga-ga realism factor we have all been waiting for--and best thing we don't have to buy all our music over again.

Yep, seen this one... problem there is you still need a proper setup for BAACH -- and there is the added expense. I'm not really striving for the ultimate realistic system, but something that is just "good enough" for me -- a happy medium that can be applied to the current setup and gear I already have.
 

Zzzzz...

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Watching this made me realize how much I wish Sean would do more research in this area.
 

Frgirard

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Earl Geddes are not a fan of a wider directivity.

Its importance in loudspeaker design for small rooms will be noted. The idea of an “ideal” directivity will be examined and it will be shown that CD alone is not enough, in a small room one needs a narrow directivity that is also CD.


The Summa has a particularly high directivity, which is desirable in a small room (another topic altogether). There are also other aspects of a design that were not touched on here that play unimportant role in sonic perception, most notably dynamics. But the fact remains that without getting the polar aspects right, the system will always be sub-optimal. So do other speakers on the market compare to the Summa? I don’t know, no one else publishes dat

 

MZKM

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SoundStage does something similar but I think they test at 76 and 86dB. Usually, I find the differences to be more noticeable when you get to the 96dB region and definitely so when you get to 102dB.
76dB & 96dB
09F433F8-CE0F-43A4-B80E-818D28A58A07.jpeg
 

abdo123

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One challenge for us using the scoring is that our objective measurements did not lead to the same scores. It seems our measurements are higher resolution than what was used during the study but that is just a guess. FYI I also bough the Bose speakers that were used in the study. I will see if I can test them.

there is no way the same speakers would score the same way, because in the study people scored the speakers and now we're using the model. Sure the model is off the data of people but it would never be the same number as asking people to score it in blind conditions.

Sean Olive said the model was 'discarded' and the research discontinued, have there been any speakers measured by Harman and they used the model to predict preference? Are you referring to speakers that were never blind tested?
 

abdo123

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all this listener preference stuff is not so useful.

Unless you're masochist I'm pretty sure people buy speakers to enjoy them, I don't understand why listener preference is not important?

The model was created to predict listener preference without blind listening and drive more profits cheaper with future designs, unfortunately as Dr. Olive explained the model was dropped and wasn't really used the way it was intended.
 
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JRS

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I hear you. Last couple of years audio was dead last on my priority list. Now that I may be soon re-employed, I've started to get the hankering--and the hankering is bad in this case. I just listened with in ear phones to those demo tracks, and thought--I get why VR guys aren't so hung up about measurements when they are looking at game changing technologies. It will be a loooong time before I can afford 20K/pr loudspeakers, but at 65 I think I have one solid assault on the dream system b4 I'm dead or deaf. All the drivers in my current system are wide dispersion, and I've always had a bit of an aversion to

So within next 12 months I plan to have a BAACH system up and running.. I'll report extensively when I do.
 

JRS

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an aversion to... most horn loaded speakers. Not sure where my thoughts went :facepalm:--off to DuckDuckGo land to look at alternative high q tech (google is your enemy!).
 

sgent

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Unless you're masochist I'm pretty sure people buy speakers to enjoy them, I don't understand why listener preference is not important?

The model was created to predict listener preference without blind listening and drive more profits cheaper with future designs, unfortunately as Dr. Olive explained the model was dropped and wasn't really used the way it was intended.


It was created to create a better model than what Consumer Reports was using at the time -- which it massively did. Harman and Olive thought the best way of getting it in front of CR was to publish it, so they did. This is one of the problems having basic research done by speaker companies -- they usually don't publish their results. I got the impression that for similar pay and lab, Olive would gladly take a job as a Professor.
 

synthetic

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I find it interesting that anechoic bass quality is big part of the model. In a room it seems like, to a point at least, the deviation in the anechoic bass response doesn't really have much of a bearing on the final result. Especially when you have things like floor SBIR from different driver heights.
 
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