The ASR "objectivists tribe" ;) has to read the Keynotes at the AES160th by Lars Risbo

[Sokel]

I wrote: "for two more octaves of range beyond the directivity of the C6Bs". Beyond can be below, too, in this case it is. C6B is directive down to ~1kHz, Orbit is down to ~230Hz.

What's the listening distance?
They seem way far for nearfield monitors.

 

[MattHooper]

While proper room treatment can be useful, it is not for everyone. Just because it is applied in studios or music venues, does not mean it should be mandatory to achieve great sound. For most consumers, room treatment will also be the exception rather than the rule. If I hear some speaker needs a treated room to sound good, am inclined to question which reality the designer lives in.

Agreed.

The issue of room correction and room treatment has really blown up in the past several years in the audiophile world in particular online. You’ve got folks like Darko who seems to have had a “ come to Jesus moment” after employing room treatment in a challenging room, and now preaches to everybody The Room Is The Main Component! You need to get your room sounding right before anything else!

I certainly wouldn’t argue against room, treatment or room correction being useful obviously it can be. I have my own room renovated in a way the employs carefully placed and hidden acoustic treatment and it sounds great.

But this mantra has become repeated over and over in audiophile comment sections, and audiophile reddit etc. I feel to the point of exaggeration or being misleading.

Sure, if you stick a loudspeaker in the corner of a 12’ x 12’ room line entirely with bathroom tile you’re gonna get awful sound.

But as you point out and as Toole often reminds us: most rooms don’t sound like that. A typical room in a house tends to have a decent balance of live versus reflected surfaces with the furnishings and carpets etc.

Plus…audiophiles have long put effort into adjusting speaker and listener position in order to dial-in the best sound they can get in their room. So for audiophiles, there aren’t that many scenarios where loudspeakers are just being carelessly plunked in the worst room possible.

Audiophiles have been managing to set up extremely compelling sonic experiences in all sorts of different rooms long before this shibboleth about room treatment and room correction became the norm. Not that you can’t get better sound of course by treating the speaker room interaction. But it often isn’t required in order to get good sound (even if that sound is not perfectly optimized).

My acoustically renovated listening room sounds marvellous with any number of speakers.

But during the many years before the renaissance I was also getting fantastic sound from many loudspeakers in the same room… when it was just a normal room with a sofa, some conversation chairs, rug, etc.

I would characterize the gains in the renovated room as being refined, but not a revolution.

 

[amirm]

"Early sidewall reflections are a good thing" (or something to that effect) may be the majority position, but it is not a universal conclusion among those with expertise in the subject:

"The earlier and the greater in level the first room reflections are, the worse they are. This aspect of sound perception is controversial. Some believe that all reflections are good because they increase the listeners' feeling of space – they increase the spaciousness of the sound. While it is certainly true that all reflections add to spaciousness, the very early ones (<10 ms.) do so at the sake of imaging and coloration." - Earl Geddes

Earl's expertise is in physics and related mathematics. He has done no research with respect to reflections and ran off with a theory to design his speakers around. That then motivated him to defend that theory with no backing. So I would not quote him for anything in this topic.

Further, no one is saying "all reflections are good." It is side reflections which bring out differential perception in our hearing due to our HRTF. Ceiling and floor present the same to both ears so don't have this effect. Ditto for front and back wall reflections. These need to be managed to some extent as to not have an overly live room.

 

[amirm]

My point being, it is not bad science to prioritize minimizing the early reflections, including the first sidewall reflections.

It *is* bad science because it relies on lay intuition that reflections are echoes and hence, they must be eliminated. This invariably leads to rooms that are super dead. Ask any acoustician what the most common problem they see in rooms that are "treated" and they will tell you this.

Science says this:

1. An empty room is likely to have a very high reverberation time. This can be dealt with using dedicated acoustic products or furnishings. Dedicated listening rooms/theaters opt for the former, everybody else, the latter. For multichannel listening where the spatial aspects are in the content, you want to be around 0.2 to 0.3 RT60/Topt. For general music, 0.3 to .6 (assuming reasonable room size).

2. Sidewalls should be left reflective by default unless you conduct your own research into what you should have. Such reflections provide a more diffused soundstage which better matches realities of what a live concert sounds like. If that is not what you want, you can get a speaker with narrower dispersion or block side walls.

3. What you do with floor/ceiling/back and front walls is about #1 above.

My experience is that with studio produced content (rock, pop), you tend to want a less reverberant space. For anything resembling live music, then more reflections add to the enjoyment of content. If you listen to a mix as I do, then you want to go RT60 of around half a second.

There is no defensible position to say that sidewall reflections should be absorbed by default.

 

[amirm]

By the way, there is research that shows even if off-axis response is poor, listeners prefer to have side wall reflections than not.

Research also shows (by McGill University) that people mixing music are able to actually do a better job with side wall reflections!

 

[amirm]

Regardless of this, you still need to consider the acoustics of the room the test was performed in (which you probably don't believe matters), the quantity of listeners, and it would make sense to test several narrow broadband constant directivity speakers before one actually claims anything objective.

Proponents of that should do that kind of research. The research that we do have shows that listeners tend to like side reflections which gives an advantage to wide dispersion speakers. My own preference is such after listening to hundreds of speakers.

As far as I am concerned, a narrower directivity speaker is fine as long as it doesn't make compromises to get that. These are second order effect that are not nearly as important as getting on and off-axis response right.

 

[amirm]

In the Harman room, the rear wall is partially covered with 4" (10 cm) absorption panels. Not a good choice when the reflections arrive so late in time and it will effect spaciousness and development in a negative way.

That room is used for different kinds of studies as it has no speaker shuffler. You can see the front of the room better in this picture I took:

Behind that projection screen there is a rotating column that lets you/them test three different in-wall speakers. The speaker setup is also used for multichannel research of Auto EQ systems in a few papers.

The room was built to be IEC compliant so has a lot of absorption that is not recommended for people to deploy. Its purpose is to have a room whose results can be replicated by others.

 

[kyuu]

Behind that projection screen there is a rotating column that lets you/them test three different in-wall speakers.

Oh that's interesting, I don't remember ever hearing that room had a speaker shuffler for in-walls.

The room was built to be IEC compliant so has a lot of absorption that is not recommended for people to deploy. Its purpose is to have a room whose results can be replicated by others.

Do you happen to know which IEC standard we are talking about? There are an awful lot of them...

 

[Duke]

I see the advantage of “no panels“, but there are some things directivity can't do.
You have to point the speaker somewhere (probably the listening position) and on the wall behind there will be reflection, unless one uses panels. And diffusion is another thing impossible for directivity.

Yes, there are wall interactions that high directivity cannot avoid, but high directivity does allow you to "pick your fights" to some extent. And imo the more "acoustic treatment" you can build into the loudspeaker via radiation pattern control, the less you'd need to do on the walls of the room itself in order to approach optimum conditions (within the room's physical constraints).

Earl's expertise is in physics and related mathematics. He has done no research with respect to reflections and ran off with a theory to design his speakers around. That then motivated him to defend that theory with no backing. So I would not quote him for anything in this topic.

I'm aware of one study Earl did with respect to reflections, but he did not publish as his wife and partner in the project, psychoacoustician Lydia Lee, felt that the data was not strong enough to justify publication. Here is a copy-and-paste of his post on the topic from another forum:

"Dr. Rumsey's comments remind me of an unpublished study that Lidia and I did looking at near wall versus far wall reflections. We asked listeners to define the phantom source locations in the two different configurations. We did not publish because the results were not stable enough for Lidia to agree to publish. (The task was too difficult for the untrained listeners.)

"However, to me, it was clear that a far wall reflection offered a much clearer localization than a near wall reflection. This is critical to understand another rationale for why I toe-in my speakers: to avoid a near wall reflection even though it likely increases the far wall reflection - better imaging."

Edited to add: Earl's resume' is on his website, evidence that his experience and expertise goes well beyond what is implied by the words "physics and related mathematics":

http://www.gedlee.com/downloads/Earl_resume.pdf

My recollection is that Floyd Toole cites Earl Geddes in his book, but I'd have to dig a bit to confirm that recollection.

Further, no one is saying "all reflections are good."

Agreed, probably not.

I think Earl's main point was that all reflections contribute to spaciousness, but the early reflections can be detrimental to imaging..

It is side reflections which bring out differential perception in our hearing due to our HRTF.

Yes, the ears being in the horizontal plane gives them the ability to localize sound sources well in that plane. And it also makes them more sensitive to the effects of early reflections in the horizontal plane, the broadening of ASW due to strong early same-side-wall reflections being an example. My understanding is that most listeners prefer to enjoy the image-broadening effects of these early same-side-wall reflections rather than forgo them for other benefits. But some people prefer a different set of tradeoffs.

Ceiling and floor present the same to both ears so don't have this effect. Ditto for front and back wall reflections. These need to be managed to some extent as to not have an overly live room.

Agreed.

 

[NTK]

Do you happen to know which IEC standard we are talking about? There are an awful lot of them...

I believe it is in this one.

IEC TR 60268-13:1998

webstore.iec.ch

 

[kyuu]

I believe it is in this one.

IEC TR 60268-13:1998

webstore.iec.ch

Sound system equipment. Part 13: Listening tests on loudspeakers

Applies to loudspeakers intended for household systems and environments. Although specifically designed for loudspeakers that are separate sound system components, the procedures, with minor changes, are applicable also to other devices such as radio receivers and television sets. Gives recommendations for the setting up, performance and evaluation of listening tests on loudspeakers. Recommendations about the room size, acoustical treatment and measurements, arrangement of loudspeakers and listeners, and environmental conditions are given. Experimental procedures are described, including recommendations on the choice of music and speech programme material and the processing and presentation of the final data. Has the status of a technical report.

Yep, sounds like that's the one. Thanks!

 

[Duke]

It *is* bad science because it relies on lay intuition that reflections are echoes and hence, they must be eliminated. This invariably leads to rooms that are super dead.... There is no defensible position to say that sidewall reflections should be absorbed by default.

Agreed! THAT approach (absorption) to minimizing early same-side-wall reflections IS (imo) bad science.

And THAT has never been what I have advocated (nor Earl). From a post earlier today:

And just for the record, I'm an advocate of loudspeaker directivity control and/or manipulation, rather than absorptive room treatment, as the way to get there.

"there" being, in the context of that post, achieving "a sufficient time gap between the direct sound and the strong onset of reflections." I can get specific about a way to do that without resorting to absorption if you would like, but I would be talking about something I do in my products.

By the way, there is research that shows even if off-axis response is poor, listeners prefer to have side wall reflections than not.

Was this a comparison of having a single sidewall reflection versus having no reflections? Or was it a comparison of absorbing the first sidewall reflections versus not absorbing them? Or something else?

Research also shows (by McGill University) that people mixing music are able to actually do a better job with side wall reflections!

Is that paper available? I'd like to read it. What I've observed in the (admittedly few) studio control rooms I've been in is a main-monitor-setup-and-sidewall geometry that precluded early reflections at the main mix position.

Thank you for conversing with me about this.

 

[bmc0]

It *is* bad science because it relies on lay intuition that reflections are echoes and hence, they must be eliminated. This invariably leads to rooms that are super dead.

Earl's approach is not so different from what you are suggesting; the main "disagreement" is exactly how early the first strong reflections should be. Earl has said that his room is very live (except at low frequencies) in order to preserve the spaciousness that lateral reflections afford. His use of high-DI speakers is to attenuate some of the very earliest reflections without decreasing the later energy much. Only the ipsilateral first sidewall reflections are attenuated with this kind of setup; the contralateral ones are unaffected or even enhanced compared to a typical configuration with wide directivity speakers.

 

[Sal1950]

While proper room treatment can be useful, it is not for everyone. Just because it is applied in studios or music venues, does not mean it should be mandatory to achieve great sound. For most consumers, room treatment will also be the exception rather than the rule.

Nothing is mandatory, it's only icing on the cake for great overall system sound. But then we're not your average consumer but definitely a outlier crowd.

2. Sidewalls should be left reflective by default unless you conduct your own research into what you should have. Such reflections provide a more diffused soundstage which better matches realities of what a live concert sounds like. If that is not what you want, you can get a speaker with narrower dispersion or block side walls.

How many today are trying to "matches realities of what a live concert sounds like" ? Outside of Classical fans and live concert recordings, the vast majority of todays music are total studio creations and "faking" a live concert event isn't quite IMO what the engineers-artists have in mind. Yes they may have the creation of a pin-point imaging soundstage at the rooms front, but I believe that's something quite different. Having a active room adding counterfeit ambiance may be a preference but I don't believe a proper goal for modern 2ch.

 

[kyuu]

Only the ipsilateral first sidewall reflections are attenuated with this kind of setup; the contralateral ones are unaffected or even enhanced compared to a typical configuration with wide directivity speakers.

I've only seen ipsilateral/contralateral used in an anatomical context, e.g. my left leg is ipsilateral to my left arm but contralateral to my right leg. Am I correct in assuming that, in this context, ipsilateral reflections would mean left wall reflections for the left speaker (and vice versa for the right speaker), while contralateral would mean right wall reflections for the left speaker (and vice versa for the right speaker)?

 

[amirm]

Is that paper available?

It is an AES paper:
The Practical Effects of Lateral Energy in Critical
Listening Environments

"2.3 Subjects’ Preference
After the experiment each subject was asked which
acoustic treatment created the best listening condition for
mixing. Eight subjects decided it is Diffusion, seven decided
Absorption, and eleven decided Reflection. We decided to
test subjects’ level preference and variance performance
based on that information (Fig. 11)."

 

[amirm]

How many today are trying to "matches realities of what a live concert sounds like" ? Outside of Classical fans and live concert recordings, the vast majority of todays music are total studio creations and "faking" a live concert event isn't quite IMO what the engineers-artists have in mind.

If you listen to a band playing, it lacks pinpoint imaging. Instead, you hear a diffused soundstage where everyone is playing. This is what I meant by what live sound. Huge amount of studio recordings have this aspect as evidenced by a ton of studio recorded tracks used in audio show demos.

 

[Oddball]

It is an AES paper:
The Practical Effects of Lateral Energy in Critical
Listening Environments

"2.3 Subjects’ Preference
After the experiment each subject was asked which
acoustic treatment created the best listening condition for
mixing. Eight subjects decided it is Diffusion, seven decided
Absorption, and eleven decided Reflection. We decided to
test subjects’ level preference and variance performance
based on that information (Fig. 11)."

View attachment 537132

Based on statistics, completely irrelevant. Sample is way too small to draw any conclusions. I already pointed out this before - you can't use statistics as a separate branch of science to verify ill funded research where sample rate is so low that it becomes inconsequential.

Are these better than having nothing at all? Well IMO not really. They are just random occurrences that support nothing at all. Sample rate is what is killing audio research as it requires a sample that is not commensurate with the funding that is available to the industry.

Nothing to do with Amir - he is just fighting the way through these arguments.

 

[Sal1950]

If you listen to a band playing, it lacks pinpoint imaging. Instead, you hear a diffused soundstage where everyone is playing. This is what I meant by what live sound. Huge amount of studio recordings have this aspect as evidenced by a ton of studio recorded tracks used in audio show demos.

In my experience, which are 90% modern studio multi-track recordings, having overly live "point of first reflection" side walls only serves to blur and lose image focus of the front soundstage. From what I've seen of studio photos, the environment the mixing rooms used to create the mix are quite dead also?

 

[amirm]

Based on statistics, completely irrelevant. Sample is way too small to draw any conclusions. I already pointed out this before - you can't use statistics as a separate branch of science to verify ill funded research where sample rate is so low that it becomes inconsequential.

I don't know what you are talking about. International audio standards have been established with testing using just a handful of trained listeners. The context here was that professionals would not at all like reflections. The data sharply shows that assumption is wrong. It does this powerfully and highly convincingly. For people who claim professional like dead rooms, the stats would have had to be completely on their side.

Are these better than having nothing at all? Well IMO not really. They are just random occurrences that support nothing at all. Sample rate is what is killing audio research as it requires a sample that is not commensurate with the funding that is available to the industry.

This is the participants:

"1.3 Subject Pool
The subject pool was composed of professional recording
and mixing engineers from the Montr´eal area, editors
and producers, recording educators, and students of McGill
University’s graduate program in Sound Recording. The
subject pool consisted of 26 individuals ranging in age
from 24 to 63 and included both males and females. The
subjects averaged over 10 years of formal musical training
and approximately 10 years of production experience
(Fig. 6). Subjects were evenly split between those whowork
primarily on classical or jazz and those who work primarily
on pop and rock productions."

This is a very large study for this domain.