Absorption only on front wall?

[DanielT]

I think it can look quite nice but taste will vary.
View attachment 275102

View attachment 275103

Nice.

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In the link below, various solutions are tested, measured and evaluated. Okay, it's a classroom, but it can be seen as a bit of general information that TS (and others) might find interesting. Perhaps get inspiration from:

The Abstract and Conclusions in the report explains it all well. Okay, the report is about a classroom with lots of students and speeches. Not music, but still.

The Effect on Room Acoustical Parameters Using a Combination of Absorbers and Diffusers—An Experimental Study in a Classroom

Several room acoustic parameters have to be considered in ordinary public rooms, such as offices and classrooms, in order to present the actual conditions, thus increasing demands on the acoustic treatment. The most common acoustical treatment in ordinary rooms is a suspended absorbent ceiling...

www.mdpi.com

 

[Thomas_A]

1.5 to 2 inches will only absorb high frequencies of which there is not a lot behind your speakers. Whether you need that kind of absorption there depends on how much you have overall. If the room is already dead, you don't want to put more there.

It can be if you have large toe-in.

But I agree damping walls should be designed to work down to approx 100 Hz, eg perforated panels above glass wool. EQ for the remaining peaks. And damping wall behind the speakers make less damage than doing it at the listening position. I find damping there quite unpleasant both for normal conversations and audio. Like being inside a ”box with pillows.” Annoying.

 

[Bjorn]

Nice.

____
In the link below, various solutions are tested, measured and evaluated. Okay, it's a classroom, but it can be seen as a bit of general information that TS (and others) might find interesting. Perhaps get inspiration from:
View attachment 275115

The Abstract and Conclusions in the report explains it all well. Okay, the report is about a classroom with lots of students and speeches. Not music, but still.

The Effect on Room Acoustical Parameters Using a Combination of Absorbers and Diffusers—An Experimental Study in a Classroom

Several room acoustic parameters have to be considered in ordinary public rooms, such as offices and classrooms, in order to present the actual conditions, thus increasing demands on the acoustic treatment. The most common acoustical treatment in ordinary rooms is a suspended absorbent ceiling...

www.mdpi.com

They are measuring with methods that have little or no relevance to small room acoustics. Studies like these are simply misleading. Few understand small room acoustics.

 

[FrankW]

I have not yet chosen the speakers for the room, but smooth off-axis response will be a hard requirement for whatever I choose.

Having read Dr Toole's book, seems all the blind listening test evidence so far, points to this feature being preferred by listeners in living rooms. Is this what guides you also?

I’m remodelling my living room and have the opportunity to treat the wall behind the speakers with 1.5” - 2” of absorption.

I don't recall any blind listening tests showing this to be preferred in living rooms. Perhaps I missed it? One good thing about front wall placement, is that you will always see it when listening. Dr Toole states that's very influential on what one hears.

 

[Bjorn]

Having read Dr Toole's book, seems all the blind listening test evidence so far, points to this feature being preferred by listeners in living rooms. Is this what guides you also?

I don't recall any blind listening tests showing this to be preferred in living rooms. Perhaps I missed it? One good thing about front wall placement, is that you will always see it when listening. Dr Toole states that's very influential on what one hears.

That's dependent on the directivity of the speaker, when the reflections arrive in time and in level, and which again is effected by how to the rear wall is treatet (or not). So pointing to a blind test that doesn't take into account the variables is moot.

 

[FrankW]

So pointing to a blind test that doesn't take into account the variables is moot.

What blind test?? Can you point me to it/them? Thanks

 

[Bjorn]

What blind test?? Can you point me to it/them? Thanks

Your quote: "I don't recall any blind listening tests showing this to be preferred in living rooms"
But that totally depends. Besides what I previously mentioned, the angle of the specular reflections will come into play. Which again is related to the rooms dimension and how it's laid out. Thus, a blind test will never be able to give an universal answer.

 

[FrankW]

Your quote: "I don't recall any blind listening tests showing this to be preferred in living rooms"
But that totally depends. Besides what I previously mentioned, the angle of the specular reflections will come into play. Which again is related to the rooms dimension and how it's laid out. Thus, a blind test will never be able to give an universal answer.

My quote was very specific to front wall treatment

I’m remodelling my living room and have the opportunity to treat the wall behind the speakers with 1.5” - 2” of absorption.

I see now you sell acoustic treatment. Can you please link the blind listening tests that show what that totally depends on, specular reflection angles, layout etc, etc, etc.
I'm simply asking you to link the double blind listening tests that support you contention, much like smooth speaker off axis. That's all.

 

[Dal1as]

Small room acoustics need to be treated differently than larger auditoriums and such.

Front wall treatment would mainly be for SBIR from your LCR. Distance from the front baffle to the wall, the speaker, etc, all matter but 5 inch bass absorption panels would be needed at the least.

What's your goal and budget for this room. A lot of different routes you can go if it's not built yet.

Diagram of the room?

 

[Bjorn]

My quote was very specific to front wall treatment

I see now you sell acoustic treatment. Can you please link the blind listening tests that show what that totally depends on, specular reflection angles, layout etc, etc, etc.
I'm simply asking you to link the double blind listening tests that support you contention, much like smooth speaker off axis. That's all.

You don't seem to understand the point and you may want to read it again. And what you're asking about blind tests about is actual well documented inn who you are referring to (Toole/Harman) in blind tests.

 

[FrankW]

You don't seem to understand the point and you may want to read it again. And what you're asking about blind tests about is actual well documented inn who you are referring to (Toole/Harman) in blind tests.

Ok, so you can't link any such tests. Thanks and apologies, I thought as someone who sold treatments you would have a great many at your finger tips.

 

[DanielT]

They are measuring with methods that have little or no relevance to small room acoustics. Studies like these are simply misleading. Few understand small room acoustics.

I agree, you can't draw straight parallels. Different conditions and challenges. But what is used, or can be used as diffusers and absorbents for example, is the same (aside from physical size and shape).

Home HiFi advantage of being able to use EQ. Disadvantage compared to live, of course, nowhere near the dynamics of the music. And so on.

Edit:
Having said that. I will admit that the study done in classrooms, #21 was pretty much OT.

 

[subframe]

What's your goal and budget for this room. A lot of different routes you can go if it's not built yet.

Diagram of the room?

The goal is to end up with a system and room that allows for enjoying music casually - with friends over, during dinner, relaxing in the evening, but which also sounds *good enough* that if something good comes on and I want to focus and really listen, I can do so. Ultimate fidelity is not the goal - I have another dedicated listening room where I can pursue that goal should I wish. Budget is flexible - whatever I do will not be a significant portion of the remodel budget, trust me lol. However, aesthetics do matter - it's our living room and it cost a lot of money to get it done the way we want, so I'm not going to want to stick 4" absorbers or corner traps everywhere willy nilly.

I've attached a diagram of the room. Circled in green are the only available places for treatment other than the front wall. Everything else is either glass or kitchen cabinets. Red circles are where the speakers will go, of course.

 

[subframe]

Having read Dr Toole's book, seems all the blind listening test evidence so far, points to this feature being preferred by listeners in living rooms. Is this what guides you also?

I don't come to this from Toole, but from years of experience in studios, lots of which were imperfect rooms. For the curious, those rooms lead to an interest in acoustics, which leads to an understanding that good off-axis behavior can help ameliorate problems in the studio, and with a little further thinking, in domestic rooms too. Same science as Toole, but arrived at from a different direction.

I don't recall any blind listening tests showing this to be preferred in living rooms. Perhaps I missed it? One good thing about front wall placement, is that you will always see it when listening. Dr Toole states that's very influential on what one hears.

As stated, my front wall is the only significant and, as far as I understand, effective place to put treatment. Given that, I'm considering doing so, and curious if it would be beneficial. I'm not starting from blind-test preferences and working from that, I'm starting from the physical reality of my room and working toward a good, effective solution, whatever that may be.

 

[Bjorn]

That rear corner is worth doing something about. Treatment on the other side may be a waste though.
Treating the front wall is definetly better than nothing. It will reduce flutter echo, effect later arriving reflections, and possible also early ones depending on the directivity of the speakers and type of treatment.

 

[FrankW]

Same science as Toole, but arrived at from a different direction.

Interesting, Toole's research and the hundreds of studies he cites in his books are based on double blind listening tests. Many of the ones specifically for loudspeakers off axis were done by him starting at the NRC, then continued under his guidance at Harman. There was also some parallel research in Europe as well Archimedes project (?) IIRC from book. You are saying there were alternate double blind tests done by studios that arrived at the same conclusions? Was this data published and can you cite it? Would love to read, thanks. There are links on this site to some studio type research, but it was actually prompted by studio types reaction to Tooles findings. Some fascinating results.

I'm not starting from blind-test preferences and working from that, I'm starting from the physical reality of my room and working toward a good, effective solution, whatever that may be.

Not quite sure what you mean here. The double blind listening tests for example, speakers on/off axis above, are very much based in physical reality, not sighted, subconscious biases etc imaginary. I was simply asking if there was such physical reality data for front wall treatment. If not, no big deal, it's your room and that type of placement will be very visible when listening, which may be all that is needed.

 

[FrankW]

Treating the front wall is definetly better than nothing. It will reduce flutter echo, effect later arriving reflections, and possible also early ones depending on the directivity of the speakers and type of treatment.

But no DBT listening test data for listener preferences of this assertion

 

[subframe]

@FrankW I'm not going to reply to you after this, but I will just say this: Toole's research is great and invaluable, but he was not the first to discover that sound waves propagate in rooms and interact with room boundaries. That basic knowledge has led many people to do lots of research, and so to arrive at the same conclusion even if Dr Toole was not involved: 'generally but especially in rooms where reflections cannot be or are not managed, smooth off-axis response is beneficial'.

 

[FrankW]

@FrankW I'm not going to reply to you after this, but I will just say this: Toole's research is great and invaluable, but he was not the first to discover that sound waves propagate in rooms and interact with room boundaries.

Sorry if you're offended, but that's a complete red herring/strawman. The discussion was specifically smooth off axis speakers and front wall treatment.

That basic knowledge has led many people to do lots of research, and so to arrive at the same conclusion even if Dr Toole was not involved

Maybe, just not anything you can cite whatsoever. It's ok, have fun building your room, sorry for the tough, uncomfortable audio science questions.

 

[youngho]

@FrankW I'm not going to reply to you after this, but I will just say this: Toole's research is great and invaluable, but he was not the first to discover that sound waves propagate in rooms and interact with room boundaries. That basic knowledge has led many people to do lots of research, and so to arrive at the same conclusion even if Dr Toole was not involved: 'generally but especially in rooms where reflections cannot be or are not managed, smooth off-axis response is beneficial'.

Hi, in the third edition of Sound Reproduction, Toole references Ando, Y. (1977). “Subjective Preference in Relation to Objective Parameters of Music
Sound Fields with a Single Echo,” J. Acoust. Soc. Am., 62, pp. 1436–1441, writing "Adding absorption to the front wall, behind the loudspeakers, reportedly improved image localization and reduced coloration" and "Memo for Listening room recommendations: add sound absorbing material to front wall."

Definitely consider some sort of scatter plate in front of the 2" of absorption, perhaps something like the RPG BAD panel. Looking at your diagram, the total amount of absorption seems likely to be relatively low, anyway. No offense intended, but the constraints you've shown will significantly limit the performance of your reproduction system. Of course, you should consider speakers specifically designed for on- or near-wall positioning.