# Can you overtreat/overdamp a listening/HT room?



## Gregr (Nov 2, 2010)

After reading an article in a popular Audiophile mag, one I try to read most of each month. I felt there was one article that was very different. I again looked over the article and there were a few things that now did stand out as a little light on critique and detail. The article was spread out over a dozen pages or so with a total of 5-7 leaves (verso and/or recto) total dialog. The article title was about a $1M listening room but the article seems more about the trip, buying LP's at a NJ Market, eval of the New Ford Edge and sound system and lots of other critical stuff.

The actual written dialog about the sound room and system, the title topic, consisted of one of two columns on one leaf. The article did mention a few building materials and construction considerations. included were names of the materials and Architects/Engineers and brief mention of "acoustical Engineer" specifically. And there was no real critique as you would expect for such a grand effort. There were some superlatives and even a little emotional stuff about the Wilson Alexandria's but fell way short of a total package critique.... Not like writers to miss an opp to write on and on about all of the details. Like maybe the room was not up to expectation. I don't know but after reading I did come away with a question. 

All of that article seems different but I a have a question that leads to my real question. 
Can you "Over-dampen a room"? And the real question is: 

My speakers sound great (matched pair of B&W DM303's especially) if I am standing 3 ft away from one I cannot tell you which speaker is actually playing what I hear (to a very high degree). If I use 5.1 speakers I can point out the Mission 765's sound track. Will damping improve my speaker invisibility?
If I over-damp will my speakers become obvious or if they are well matched will they disappear even further. I have a sense that all of the speakers flaws will add or multiply. 

Thank You

Greg

Read more: When is room treatment needed - Page 8 - Home Theater Forum and Systems - 
HomeTheaterShack.com


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## eugovector (Sep 4, 2006)

Yes, a dead or anechoic room will not only fail to reproduce 3 dimensional sound that envelopes you, but will also be uncomfortable to be when the movie is off.


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## bpape (Sep 14, 2006)

Yes you can overdamp a room - and you can do it in a variety of different ways. 

That said, I have no idea of your situation and would strongly consider looking at speaker/seating position to start with. Unless the room is very very small, what you hear at a 3' distance isn't really relevant to proper imaging.

Can I assume that the Missions are your surround channels or are they a 2nd set of speakers used for HT duties?

Bryan


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## DanTheMan (Oct 12, 2009)

I'd say this,"it should be harder to over damp an HT with surround sound then one with just stereo." Of course that depends on the program material and how much ambiance the engineer put in there. Many movies I've watched do not have much SS. Fortunately the newer post processing that can be done in modern receivers really helps. I'm shocked at how well it works.

Dan


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## Zeitgeist (Apr 4, 2009)

I was in an anechoic chamber a little while back.. used for automotive testing (Bigger room).

The fact that it is so dead - makes it a little uncomfortable..

Takes a lot of treatment to make a room that dead though..


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## Mark Techer (Jan 17, 2008)

Zeitgeist said:


> I was in an anechoic chamber a little while back..


Whilst I have not been inside an anechoic chamber, I have been inside a THX certified dubbing stage with no sound playing and that was so quiet it was a little unnerving. 

Yes I believe it is possible to over dampen a room. I have a friend and I think he crossed that line a while ago. The room sounds good, I just think that it could sound better if he had more diffusion and less absorption.


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## mtbdudex (Jan 2, 2008)

Zeitgeist said:


> I was in an anechoic chamber a little while back.. used for automotive testing (Bigger room).
> 
> The fact that it is so dead - makes it a little uncomfortable..
> 
> Takes a lot of treatment to make a room that dead though..


We have an anechoic chamber at work, our main NVH lab (I work for auto OE) for isolating vehicle issues.
You can view those pictures and hear about other peoples experiences, but it truly is...eerie being in there.
I've been in there too many times while launching vehicles and reviewing countermeasures for "issues" and their associated pc cost/tlg cost tradeoffs.
-we need $x.x cost for this dampner to reduce this 3rd order harmonic which is causing this ....which will lead to increase JDpower score unless we act now
etc etc

Our audio guys also have a dedicated room for their vehicle audio testing, but it's more a sound controlled room and an acoustic room. 
Sound controlled via keeping unwanted sounds from penetrating into the room while testing. Then, they put different treatments on the inside walls of the room depending on the type of outside environment they want to replicate even while testing inside the vehicle. Its all the vehicle system interaction stuff....
The audio room was built 3 years ago, just as I was building my HT, I enjoyed talking with them while that project was being done, neat stuff.

With that said.....hopefully nobody would just throw treatments around their HT w/o some scientific basis for doing so, that's a recipe for disaster.
Rules of thumb are ok to start as planning, but need to grasp the basis for those before actually doing.


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## Zeitgeist (Apr 4, 2009)

Very interesting Mike..

The chamber I was in - was a little less interesting.... but was at a neat facility -the Center for Automotive Research at The Ohio State University.. Can you say hydrogen fuel cell powered dragster?


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## Gregr (Nov 2, 2010)

Thanks for all of your thoughts and exp. You know I had never considered the effect of an anechoic chamber. I mean I never thought of going that far, but I really wouldn't have too if I put too much damping in, it can have that kind of effect on music frequency segments.

I was thinking of Tx for first order sound reflection and something to optimize wide low frequency effects. 

Hopefully at some point in the future I could ask Bryan to give me a few tips. But right now the REW prog is pretty sophisticated stuff. Ive gotta get a mic and start playin'..., haven't even got REW calibrated yet. 

Greg


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## Tufelhundin (Jan 25, 2010)

I want to say that the COSI in Columbus Ohio has an area like this, for I remember walking in there and all I could hear was crickets and they were LOUD!!!! Yes...I have tinnitus.:rofl:

Anyway, they would have you clap your hands and the sounds stopped at your hand ....it was crazy.


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## monomer (Dec 3, 2006)

Yes, but you guys are talking about listening to sounds you are generating yourself from within the room. How about sounds that were recorded in another venue and contain all the appropriate ambient cues to that space? Playing that recording back into an acoustically 'dead' room, I would think, should make it sound very much like you were in that space where it was recorded and not in a 'dead' room. I'm NOT referring to 2-channel stuff that requires reflections from behind the listener but rather 7.1 or at least 5.1 where sound is generated from all directions around the listener thereby providing the appropriate delay reflections without need for reflective surfaces at all to impose your room's acoustical signature on top of the recorded ambient cues. If anything, I think that would muddy-up the sound of the source recording.

My theater sounds pretty spooky dead to anyone talking or clapping etc within the room but the moment a movie starts or music begins playing all that eerieness goes away and you are transported into another space where the sounds are clear and imaging can be almost pin-point... in this respect very similar to wearing headphones except there is a front soundstage and the music is in the room instead of just confined to the inside of your head.


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## DanTheMan (Oct 12, 2009)

Excellent point Monomer. This brings up the same problem however--not all recordings have a lot of ambient signals. Movies are typically much better than music in this regard. If it's strictly HT, it would be much harder to over damp it. None the less, if you have SS processing, it should be more than doable even in a 'too dead' room.

You got to love technology,

Dan


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## Mark Techer (Jan 17, 2008)

monomer said:


> Yes, but you guys are talking about listening to sounds you are generating yourself from within the room. How about sounds that were recorded in another venue and contain all the appropriate ambient cues to that space? Playing that recording back into an acoustically 'dead' room, I would think, should make it sound very much like you were in that space where it was recorded and not in a 'dead' room.


The goal is to have control over reverberation so that the room itself does not "change" the sound of the recording. You can have too much of a good thing and speakers pending, you might actually need some refection and diffusion for them to sound their best - AKA Dipoles. 




> My theater sounds pretty spooky dead to anyone talking or clapping etc within the room but the moment a movie starts or music begins playing all that eerieness goes away and you are transported into another space where the sounds are clear and imaging can be almost pin-point... in this respect very similar to wearing headphones except there is a front soundstage and the music is in the room instead of just confined to the inside of your head.


Which is pretty much what I have achieved in my own room. At the screen end, I have no slap echoes and the imaging is amazing. The rear of the room is more live and was needed to get the best from the surrounds.


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## DanTheMan (Oct 12, 2009)

Mark, what you have sounds very much like my ideal room. Do you have no slap echo in the rear as well?

Dan


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## Tufelhundin (Jan 25, 2010)

Mark Techer said:


> The goal is to have control over reverberation so that the room itself does not "change" the sound of the recording. You can have too much of a good thing and speakers pending, you might actually need some refection and diffusion for them to sound their best - AKA Dipoles.
> 
> 
> 
> ...





I'm hoping that in the near future I will be placing an order for Kit #1 and #3 from GIK, for my theater is in a concrete basement with tile floor and it needs all the help it can get. The bold above has me confused for bpape suggest putting the monster traps in the rear of the room. Since my listening area will be 12ft across I was planning on putting them 6" apart center rear with 244 x2 on the out side them with tri's in each corner.

So should I deaden the front wall even more so than the rear? Or could I use some 244's maybe x4 across the front wall? I was planning placing 242 at 1st and 2nd reflection points....

Trying figure out what i would need to best tame this room.....and the bold above made me wonder if I know what in the world I'm doing..


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## Mark Techer (Jan 17, 2008)

DanTheMan said:


> Mark, what you have sounds very much like my ideal room. Do you have no slap echo in the rear as well?
> 
> Dan


Hi Dan,

No, there is a bit in the back of the room and why I have started adding diffusion. I was going to add more absorption, however research suggested that I am better to keep this end of the room "live" and break up any reflections. In the listening seats, these reflections are not offensive, however I did hear them when standing against a wall near the EQ rack when giving a demo once. I like the idea of "clouds" so might make some of them. I noticed that most hang from chains, so thought I could then even angle the panels. 

Overall I am very happy with how the room has turned out (especially considering the low budget I had for this room) so if I am able to make an improvement, all good. If not, then like so many things I do, I remove it and make something else.



Tufelhundin said:


> I'm hoping that in the near future I will be placing an order for Kit #1 and #3 from GIK, for my theater is in a concrete basement with tile floor and it needs all the help it can get. The bold above has me confused for bpape suggest putting the monster traps in the rear of the room. Since my listening area will be 12ft across I was planning on putting them 6" apart center rear with 244 x2 on the out side them with tri's in each corner.
> 
> So should I deaden the front wall even more so than the rear? Or could I use some 244's maybe x4 across the front wall? I was planning placing 242 at 1st and 2nd reflection points....
> 
> Trying figure out what i would need to best tame this room.....and the bold above made me wonder if I know what in the world I'm doing..


I did make the front of my room more dead than the rear.

Attached is a bitmap of what my room looks like.










So roughly the 1st 1/3rd is fully (walls) treated and the back 2/3rds are half treated. When I stand in front of the screen and clap my hands, the only thing I hear is the clap. It sounds odd. At the back of the room, I can hear both the clap and some slight reverb. It is not offensive. It seems to enhance the surrounds and why I am reluctant to add any more absorption.


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## Tufelhundin (Jan 25, 2010)

Interesting, thanks for your input Mark. I still have time for I put in an order, just trying to figure out the best way to do this. Once again, thanks.


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## bpape (Sep 14, 2006)

The Monsters in the rear will address primarily bottom end issues. They're not fully aborptive all the way up.

Bryan


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## monomer (Dec 3, 2006)

Think about this...

What's the difference between wearing headphones vs listening to your room speakers? The lack of the room's acoustical signature (reflections) because essentially there are no walls inside a pair of headphones and yet I never hear anyone complain that listening to music while wearing a pair of headphones is too dead sounding. To the contrary, I often hear compliments having to do with enhanced clarity and better imaging (except the soundstage is stuck inside your head because you don't have direct sound coming from each speaker reaching both ears with the appropriate delays of course). I'm thinking the room's boundaries actually detract from what is already included in the recording... which is the ambient cues from another space, the space where the recording was made or engineered. 

I think the only real dangers with adding more and more absorption are the likely risk of unbalancing the frequency response and also the need to add substantial power to pull the SPL levels back up to where the music will again sound powerful. I think its very hard to over-treat a room but rather what's far more likely is to unbalance the sound if not done properly and also when you remove reflected sound energy from a space it will need to be replaced with more direct sound energy otherwise it will sound too weak and puny and thus could be perceived as 'too dead'.


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## DanTheMan (Oct 12, 2009)

Monomer, I did a little write up that very much supports your position:
http://dtmblabber.blogspot.com/2011/02/tightening-loudspeaker-recording-and.html

I still haven't addressed the whole issue, but this will give you some supporting evidence. Depending on how things are recorded.... Oye I wish there was a standard. LEDE probably still has an edge b/c it will work well no matter what though not optimally every time all the time.

Dan


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## S_rangeBrew (Dec 28, 2010)

I am so happy to have found this thread. I've been toying with the idea of a SUPER-DAMPED room, and you folks have brought up some things I've been thinking about but didn't know if anyone else had.



monomer said:


> Yes, but you guys are talking about listening to sounds you are generating yourself from within the room. How about sounds that were recorded in another venue and contain all the appropriate ambient cues to that space? Playing that recording back into an acoustically 'dead' room, I would think, should make it sound very much like you were in that space where it was recorded and not in a 'dead' room. I'm NOT referring to 2-channel stuff that requires reflections from behind the listener but rather 7.1 or at least 5.1 where sound is generated from all directions around the listener thereby providing the appropriate delay reflections without need for reflective surfaces at all to impose your room's acoustical signature on top of the recorded ambient cues. If anything, I think that would muddy-up the sound of the source recording.


This makes sense, considering most movies are mastered in pretty dead rooms, from what the professionals posting here say.



> My theater sounds pretty spooky dead to anyone talking or clapping etc within the room but the moment a movie starts or music begins playing all that eerieness goes away and you are transported into another space where the sounds are clear and imaging can be almost pin-point... in this respect very similar to wearing headphones except there is a front soundstage and the music is in the room instead of just confined to the inside of your head.


This sounds ideal to me. I love the sound from my headphones with Dolby Headphone enabled, I'd love to transfer that isolated perfection to my home theater speaker setup.



DanTheMan said:


> Excellent point Monomer. This brings up the same problem however--not all recordings have a lot of ambient signals. Movies are typically much better than music in this regard. If it's strictly HT, it would be much harder to over damp it. None the less, if you have SS processing, it should be more than doable even in a 'too dead' room.
> 
> You got to love technology,
> 
> Dan


YES! My idea is using a "dead" room with Audyssey DSX 11.2 applied to movies AND music. It is supposed to use the extra speakers to create any directional reflections needed. 




Mark Techer said:


> The goal is to have control over reverberation so that the room itself does not "change" the sound of the recording. You can have too much of a good thing and speakers pending, you might actually need some refection and diffusion for them to sound their best - AKA Dipoles.


This jives with the reccomendation from Audyssey to use direct radiating speakers rather than dipoles.



monomer said:


> Think about this...
> 
> What's the difference between wearing headphones vs listening to your room speakers? The lack of the room's acoustical signature (reflections) because essentially there are no walls inside a pair of headphones and yet I never hear anyone complain that listening to music while wearing a pair of headphones is too dead sounding. To the contrary, I often hear compliments having to do with enhanced clarity and better imaging (except the soundstage is stuck inside your head because you don't have direct sound coming from each speaker reaching both ears with the appropriate delays of course). I'm thinking the room's boundaries actually detract from what is already included in the recording... which is the ambient cues from another space, the space where the recording was made or engineered.


You have typed eloquently the thoughts that have been in my head for awhile now. Thank you. I just got a pair of AT-AD900 headphones and paired with a Dolby Headphone amp.... it's amazing. 



> I think the only real dangers with adding more and more absorption are the likely risk of unbalancing the frequency response and also the need to add substantial power to pull the SPL levels back up to where the music will again sound powerful. I think its very hard to over-treat a room but rather what's far more likely is to unbalance the sound if not done properly and also when you remove reflected sound energy from a space it will need to be replaced with more direct sound energy otherwise it will sound too weak and puny and thus could be perceived as 'too dead'.


Yes, this is my worry. If I do this, I'm planning on using the sound absorbtion values listed http://www.bobgolds.com/AbsorptionCoefficients.htm to pick treatments that will do the job. Right now thats looking like 9"+ thick standard fiberglass batts or 6" thick rigid fiberglass boards, unfaced. On all walls and the ceiling (every square inch) and then add huge bass traps in every corner possible. Then use acoustically transparent cloth to cover it all. This should take care of everything except sub-bass below 100Hz (although it should smooth that out, also) and I will count on Audyssey subwoofer EQ to take care of that.



DanTheMan said:


> Monomer, I did a little write up that very much supports your position:
> http://dtmblabber.blogspot.com/2011/02/tightening-loudspeaker-recording-and.html
> 
> I still haven't addressed the whole issue, but this will give you some supporting evidence. Depending on how things are recorded.... Oye I wish there was a standard. LEDE probably still has an edge b/c it will work well no matter what though not optimally every time all the time.
> ...


Good stuff, thanks everyone. I am really leaning towards the "DEAD ROOM w/Audyssey 11.2 used to provided ambience" idea rather than the traditional "LIVE ROOM + TREATMENTS and EQ used to control reflections" method... which is what I currently use.


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## Gregr (Nov 2, 2010)

I have a few gut responses to your post and some questions as well. Mostly the questions are for me but I welcome any thoughts and response. But first I hope you realize that if you go to the Home Theater Shack "Home Page" or look at the top of almost any page you will see GIK Acoustics add. This company makes some great suggestions and there is at least one employee who has posted some very helpful info. 

I believe the the headphone analogy is a mute point when compared to room Tx considering headphones contain 2 to 6+ driver arrays and are great for music and are immersive for HT but lack a visceral head turning impact. I can get the same headphone experience with a speaker on each shoulder when the pair are playing a 7.1 program I can get a believable sound experience that is very involving. But now the task is ultimately how do I scale that experience to fill a 12'-14' -16' X 12'-14' 16' room? 

First, the head phone sounds great if the program provides information required. The more info on track the greater the experience but there is always something lacking when you use a headphone especially for Home Theater sound reproduction. Not only the visceral ques but also the sense of space..., right. Yeah, with headphones I can pinpoint the location of a door opening into a room. I can imagine any door I choose in my head and given ques I know what to see "in my head" but how far does the door open into your space when you have on a pair of headphones. I don't think I'm very far off here. With a speaker on each shoulder I can feel air vibes and I am a little more involved with a little more realistic sense of involvement..., there is a real sense of presence and I am always oriented. With headphones if my head is turned the wrong way or I am watching a movie laying down I loose very important information..., or worse still the info is skewed. With headphones the experience is always anemic or contrived. It works and sounds great but it is never enough it is never fully satisfying it is too much work for not enough payoff. Not unlike the American exoerience thesedays and here again most people will never complain in fact many believe it all sounds great.

Now, in a room with speakers strategically placed and a sound program designed for such a space and here I am the center of this universe the recipient of a constellation of fully applicable sounds existing in not just time but space. This type of info and ques are designated in Dolby sound formats and the like. What does dolby say about room Tx. If you speak with GIK sales or sound engineers or sound techs you will hear there is a potential for over-damping a Home Theater. 

I believe theaters have gotten this one wrong more often than right. 

I do wonder about sound programs. I have painted myself into that corner where I am dependent on science and its uniform application. I think there is allot of science out there but how much is every manufacturer cooperating. :rant: :scratch: :blink::yikes:

Greg


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## S_rangeBrew (Dec 28, 2010)

I'm going to reply to you, Gregr, but please forgive me if I misunderstood you, some of your phrasing is strange to me.



Gregr said:


> I believe the the headphone analogy is a mute point when compared to room Tx considering headphones contain 2 to 6+ driver arrays and are great for music and are immersive for HT but lack a visceral head turning impact.


Yes, regular speakers provide much more impact, I was not saying headphones could equal them, I was just agreeing that headphones do a good job simulating a acoustically "DEAD" room.



> With headphones the experience is always anemic or contrived. It works and sounds great but it is never enough it is never fully satisfying it is too much work for not enough payoff.


Have you used Dolby Headphone? I've been using it the past few weeks with my MixAmp, and it really makes the headphones seem more like a room full of speakers. The smart folks a Dolby figured out the process of the headphone sound passing through your flesh and bone made things sound a lot different than regular speakers. (just like what you pointed out with the speaker on each shoulder example) So they did some experiments and came up with Dolby Headphone which basically compensates for your boney, fleshy head. I find it to work wonderfully, and listen to all my movies and music with it turned on. 


> Now, in a room with speakers strategically placed and a sound program designed for such a space and here I am the center of this universe the recipient of a constellation of fully applicable sounds existing in not just time but space. This type of info and ques are designated in Dolby sound formats and the like. What does dolby say about room Tx. If you speak with GIK sales or sound engineers or sound techs you will hear there is a potential for over-damping a Home Theater.


I don't know about Dolby, but THX specs for real movie theaters call for as much sound damping as possible. 




> I believe theaters have gotten this one wrong more often than right.
> 
> I do wonder about sound programs. I have painted myself into that corner where I am dependent on science and its uniform application. I think there is allot of science out there but how much is every manufacturer cooperating. :rant: :scratch: :blink::yikes:
> 
> Greg


I very much enjoy THX theaters. In all their glorious "overdamping". And I think I want the same thing in my home. :dontknow:
Yes, there are a lot of people saying a lot of things. I enjoy reading it all and messing around with it as I can afford it. There is always something new out there, and I really think a lot of it is good stuff and not snake oil.


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## Gregr (Nov 2, 2010)

I admit I am not up on all of the tech as each would play out in my home. I just felt I had to throw out some of the questions I had. My biggest question being..., the science is available but is/are manufacturers paying attention. Each time Dolby offers a new configuration it offers added dimensional sound, meaning more speakers and increased damping and now dolby is recomending whole room damping. 
Is that . The greatest question, "what happened to music? I guess music is lost in an HT".

Next, I would love to read a discussion with you and I think his name is Barry.

I apologize if I make no sense, I need to write earlier in the day.

Thanks for your response. I hope your happy with the final result. I am a little anxious to hear..., it does seem like a long way to go for a Home Theater. But if that is what Dolby recommends. :spend::heehee:

Greg


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## S_rangeBrew (Dec 28, 2010)

Gregr said:


> The greatest question, "what happened to music? I guess music is lost in an HT".


I honestly don't believe there needs to be a compromise with movies and music these days. With truly acoustically transparent screens, incredible electronic room EQ like Audyssey, and incredibly musical subwoofers, I feel all sources, music and movie can be replicated with NO compromise. Add to that the much greater understanding of room acoustics these days, and it gets even better.

The days of snake oil are being replaced by the days of hard science in the world of home audio/video. If you are willing to do a little bit of reading. For example, I bought a 32ft. HDMI cable online for $12. The cheapest any store had it for was $100. The internet saved me $88. Go internet. :clap:



> Thanks for your response. I hope your happy with the final result. I am a little anxious to hear..., it does seem like a long way to go for a Home Theater. But if that is what Dolby recommends. :spend::heehee:
> 
> Greg


Yeah, I won't know for quite awhile. I currently have a wonderful home theater with a 92" 1080P screen, 7.1 Ascend Acoustics speakers, and 4" thick GIK-style (rigid fiberglass covered in cloth) acoustic treatments at all first reflection points and the rear wall. To be better than this my next home theater will have to be INCREDIBLE, and will take a LOT of time, research and money. It will be new construction, which is why a fully acoustically damped (DEAD) room will be possible. I'll also be able to incorporate an acoustically transparent screen and infinite baffle subwoofers. I won't just be going off of what Dolby or THX reccomends. Especially their reccomendations for Home Theater... they seem to treat it as a bastard stepchild vs. real theaters. But it's a good place to start.


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## DanTheMan (Oct 12, 2009)

If new construction is in the works, I would look for CLD or some sort of diaphragmatic damped walls. Combine that with more typical porous absorbers in traditional places and you should really have something incredible.

Dan


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## Gregr (Nov 2, 2010)

I have a feeling we are not talking about curtains, floor to ceiling and not single layering of damping material either. We're not just going to slow down first order reflections we are going to capture that energy. 

I get the idea of diaphragm, and expansion/contraction..., I think. the idea of room resonance below audible. Could you elaborate. I am curious about front wall and ceiling mostly. Does the idea of the money seat expand out to envelope the theater? Is the entire theater the critical listening seat. 

I guess the front wall needs to pass the slap test. I see there are three speaker boxes along the front wall so there is much audible info filling the room from the front first of all and at any given time. I would assume many things, e.g. corner Tx etc... . but Why..., and How?

Where did you find some of your best info outside of the university. Don't get me wrong, I believe..., "If you have a question - college is the answer", but I'll bet there are hundreds of ready made theories about speaker placement and wall/sound Tx. Where is that discussion going on. 

Greg :huh: :dontknow: :yikes: :nerd: :blink:


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## DanTheMan (Oct 12, 2009)

Books and control room acoustic papers mostly. Look at the list on the bottom here: http://dtmblabber.blogspot.com/
http://www.gedlee.com/downloads/Chapter 4.pdf
http://books.google.com/books?id=sG...&resnum=5&ved=0CEIQ6AEwBA#v=onepage&q&f=false

etc...

Dan


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## bpape (Sep 14, 2006)

2 channel music and mutlichannel music/HT have very very different design goals in terms of room acoustics. Yes - you can come up with a solution that will be a very good compromise and perform well for both, but it's still going to need to lean toward one or the other. 

A completely dead space isn't the proper solution for either - especially not 2 channel.

Bryan


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## Gregr (Nov 2, 2010)

Hello,

I'm surprised..., nothing outrageous has been said or let alone done. I would love for this conversation to continue. I know enough about room Tx to get myself in trouble..., that has become obvious to me. But you rangebrew have enough info to ask intelligent, though partially informed questions. These guys have a plan that can tweak what you have but most of all and the conversation I would love to be privileged to read about is your future HT. I love Music and electronics and room Tx is very interesting but I don't have a clue where to begin with my room/sound Tx so I just read. I think I am getting closer to having a question. 

Greg


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## Gregr (Nov 2, 2010)

Once I get started..., I had another thought about the Headphone vs. HT 

Very simply the headphone is equal to an HT with speakers 360% or very nearly 180% left and 180% right. there is a small seperation at the headphone however two good front speakers will compensate nicely.

But even with the room circumaurally active, like the headphone, there is going to be program info lacking. First of all if we want a realistic reproduction we still need to fill the vertical axis with speakers as well and each speaker needs programming specific to that speaker placement so lets see..., how many amplified channels? But wait, walls of speakers from floor to ceiling is only equal to a headphone. There is no program available that comes anywhere near filling that space requirement. Another reason why headphones are so unsatisfying for theater experience. The mind wants closure and so immediately creates sound placement that a headphone driver only needs to approximate sound placement for, but this is very real work and potentially tiring and/or distracting.

Headphones can take a 2 dimensional stage and develop very realistic depth and pinpoint imaging of instruments not necessarily in the order of stage appearance or any recording venue. Then there is the holographic imaging aspect of open air speakers especially that can add real sound stage depth. I imagine sound emanating from the middle of the room and moving L or R and/or F to B is somewhat controlled in the recording studio where there is a lack of vertical control. 

I believe the headphone is a flat plane and with the drivers so close to the ear the effect is 360' degrees of sound. No HT even comes close.

I'm going to end this because I'm tired and I'm having a hard time explaining to myself what I am trying to say. No proof read, no!

Greglddude:


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## S_rangeBrew (Dec 28, 2010)

bpape said:


> 2 channel music and mutlichannel music/HT have very very different design goals in terms of room acoustics. Yes - you can come up with a solution that will be a very good compromise and perform well for both, but it's still going to need to lean toward one or the other.
> 
> A completely dead space isn't the proper solution for either - especially not 2 channel.
> 
> Bryan


I hear you, and I know that is the general consensus. I'm just throwing out some ideas based on what I've learned to get some discussion going. Could you point to some specific places for information on music vs. home theater? From my listening experience with surround processing modes, I'm leaning towards them improving a stereo signal in some cases. I know the "purists" will have nothing to do with this idea..... it's a "compromise". To each their own.


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## Zeitgeist (Apr 4, 2009)

Maybe I'm misunderstanding the end objective.... but music of any kind isn't recorded in an overdamped room nor are movies mixed in dubbing stages that are acoustically dead.

I'm not trying to be a purist or question your plans... just trying to understand what you want to achieve?

An acoustically dead room isn't going to make your speakers more invisible.. it's just going to make you feel like you're the only object in the room. An anechoic chamber is an uncomfortable place to be - if that's the direction you're heading towards.


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## bpape (Sep 14, 2006)

The major difference to consider is that with 2 channel listening, you have 2 sources of sound and you count on their dispersion characteristics and the room acoustics to assist in generating a 3 (or 4 if you count time) dimensional soundstage.

With any multi-channel music or home theater, you have discrete channels to help generate the field. The front would be the same as 2 channel where you want a pure, untarnished, 3 dimensional soundstage but locked to a screen image. You damp the front to stop reflections from the surrounds from contaminating the front soundstage.

In 2 channel, you may or may not damp the front depending on the type of speaker. 

There are a lot of other things - that's just an obvious one to consider.

Bryan


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## S_rangeBrew (Dec 28, 2010)

Zeitgeist said:


> Maybe I'm misunderstanding the end objective.... but music of any kind isn't recorded in an overdamped room nor are movies mixed in dubbing stages that are acoustically dead.
> 
> I'm not trying to be a purist or question your plans... just trying to understand what you want to achieve?
> 
> An acoustically dead room isn't going to make your speakers more invisible.. it's just going to make you feel like you're the only object in the room. An anechoic chamber is an uncomfortable place to be - if that's the direction you're heading towards.


Agreed that an anechoic chamber is a wierd place to be.... but... but... but. Music is recorded in a specific environment. Could be a studio with massive damping. Could be a concert hall with strange and wonderful acoustics. Whatever it is... it gets put on the tape/CD and we listen to it on our home systems. The question is... do you want to hear what they put on the CD? Or what they heard in the music hall? Or do you want to hear what they heard in the studio when mastering it? (Not always the same thing) or do you want to hear something your room/electronic EQ has created in your room from this source?  Are any of them the "right"? Are any of them "wrong"? I posit that we are being a little arrogant if we say what someone prefers is not "right". Music is as a subjective thing as can exist.

What do I want to achieve? Something that sounds wonderful. To ME. My current room is regarded as some kind of luxury overkill by most of my friends (Im sure some of you have been there)..... but it's just a 92" screen with 7.1 surround sound and basic room treatments... yet I want to try more. You know what I mean? 



bpape said:


> The major difference to consider is that with 2 channel listening, you have 2 sources of sound and you count on their dispersion characteristics and the room acoustics to assist in generating a 3 (or 4 if you count time) dimensional soundstage.
> 
> With any multi-channel music or home theater, you have discrete channels to help generate the field. The front would be the same as 2 channel where you want a pure, untarnished, 3 dimensional soundstage but locked to a screen image. You damp the front to stop reflections from the surrounds from contaminating the front soundstage.
> 
> ...


This is where I am wondering if the something like the Audyssey 11.2 system can remove any need for "dispersion characteristics" of the room. It can emulate them. I guess I'm think of trying the "exact" science of Audyssey vs. the "inexact" science of passive "dispersion". I'm talking about takeing a "dead" room and using 11.2 DSX to give it "life". That obvioiusly means in the case of music, taking a "pure" stereo signal and processing it into a 11.2 sound. 

Thoughts?


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## bpape (Sep 14, 2006)

I'd rather make my space more conducive to allowing a more spacious sound than to apply massive amounts of processing trying to derive an 11.2 signal, the additional cost, etc. If you want to fully treat a room's surfaces, go with moderate bass control and do the rest in diffusion rather than absorption.


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## DanTheMan (Oct 12, 2009)

It certainly does come down to what you want. Processing should make for far more options, but how well t pulls that off depends on a lot of things. Changing room treatments around is far more tedious and time consuming that pushing buttons on a remote. Currently I love processing and the EQ options offered by modern receivers, but my better treated room with better speakers and no processing is still my favorite listening environment. It just images like crazy and I enjoy that effect and I use it to mix recordings. 

My experience--backed by a lot of research looks like this: 

A well damped front wall leads to better imaging, but reduced source width. In blind studies, a larger source width is preferred and that's understandable. It sounds immediately impressive--larger than life. 

Undamped side walls d/t binaural hearing and decorrelation will lead to more envelopment and a sense of space. Well damped side walls will reduce that effect, and it's been shown to be preferred in blind conditions. Crossfiring the speakers in front of the listener will increase this effect. 

The rear wall is generally less critical, but can be used to help kill the bass end of the spectrum or add a little more sense of space or even both if cleverly devised.

With HT, the rear wall can be similar to the front, but to a lesser degree b/c of our directional hearing acuity of sounds from the rear--which is actually pretty good though--and the recording method. Some recordings don't make a rear image, but more of a rear spacial effect. The post processing will effect this as well.

Many, many channel audio may still benefit from this source broadening effect so that the spacial holes will be filled in. Same can be said for stereo.

In HT, the ventriloquist effect will dominate the front image anyway. 

My 2 cents,

Dan


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## bpape (Sep 14, 2006)

And I'm exactly the opposite. The more I can do to avoid modifying the signal, the more I like it. If the speakers, source, processor, and amp are good, you shouldn't have to EQ to get it to sound like what's on the disk. That leaves the room.

IMO, EQ is a crutch to be used only when something is left that can't be dealt with any other way - or - when the user deliberately wants something that is not true to the original signal (house curve anyone???)


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## DanTheMan (Oct 12, 2009)

I don't think that makes you the opposite by any means. Still, I've never heard a room that didn't require some EQ in the modal region.

Dan


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## Gregr (Nov 2, 2010)

Math and science are a very linear derivative of and a sound experience is very dynamic occurrence. The sound reproduction world is a blend at best. In any one instant in time a sound bite is recreate-able but in the next instant sound repro requires a whole new set of dimensional, electrical, material and time requirements (to name a few) to reproduce a sound experience. Each sound instant is definable using math or other scientific to help us understand or experience/re-experience what was a unique sound occurrence. 

I like the idea of rangebrew programming a sound experience and removing the room acoustics from the equation, that all sounds logical (no pun intended..., kinda) and possibly the next step in sound reproduction. I believe where rengebrew is headed can be a very interesting stage for sound experiences and reproduction but filling a room with source components, speakers and such even with using the most sophisticated sound repro program available today is hardly enough to recreate a 1-2 hr program of live sound exp. 

what makes a movie' sound program believable or helps is that much of what is on stage is a unique sound experience and we are actually being told what to see hear feel and think about the experience/program. The easiest thing in the world to do is simply believe what is occurring and without too much thought the sound program in the movie now becomes the default experience expected the next time we are in a situation where there is an explosion and the walls collapse (I watched "Expendables" last night) the repro program just needs to come close. Actually, the next time we are in that situation we may be surprised to hear what an explosion of that size and direction and with objects reflecting and directing the sound actually sounds like. 
Hopefully/Fortunately we will never have that exact experience and in fact each and every sound occurrence is pretty much unique and our default is not to ask..., was that real???- this helps simplify sound repro so pretty much what is required is the db factor and directional q's. 

The fact that you are using a two channel system is not a deterrent to exp realistic sound repro with all its unique q's, direction, db etc. it is just that 5.1 or 7.1 is that much more involving. The added speakers and program could relieve the mind of the responsibility of creating a believable exp. so the overall effect is more satisfying or less fatiguing. 

I don't know how much misinformation the mind needs before you will wake into consciousness to say to yourself..., nah, that's not right. This will never happen with music. With music I either like it a little or I like it allot. Each new added dimension is simply a plus it makes my exp richer, easier on the ears so to speak.
I do not believe we are or sci is at a place where we can remove room acoustics from the equation and in its place put speakers with each speaker filled with sound program relevant to that time and space for purposes of repro sound programming/experience. I don't believe 11.2 programming is at that stage. I am sure we will get there because I don't believe rangebrew is the only one trying to imagine what that would be like. I'll bet that will be incredible to experience. 

I do believe sound repro science and technology is at a time and place where we understand how to best use the room limits to our advantage in producing a/the sound exp.. To add more speakers than 7.1 or 7.2 could add to the experience but also could confuse the listener in another instance. The same is probably true for room Tx (treatment). Having a dead space is like preparing a space for sound programs but not filling that space with sound program other than dead space could just catapult the listener out of the movie or sound experience and into the awareness of..., "hey, that's not right". So to speak.

Of course this is all my opinion but I do not believe you will find much difference if you were to conduct a survey of people who think about such things. I love it. But I still don't know what to do with my room and system. :rofl2:

I am going to sell my MIT speaker cables and try Kimber Kable 8VS w/Furutech Rhodium on copper Banana's. I was going to try Furutech PCOCC cable next but I can't resist this opportunity (its cheaper).
I have a 10' pair of MIT EXP 1's I have had for about a year or less and through all of my upgrades/changes they have never failed to reflect the improvements. :unbelievable:

Greg


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## Gregr (Nov 2, 2010)

Oh, I forgot to say thanks. Dan and Bryan I have to say also..., there are many educated and inspiring people here at HTS but I cannot think of any other people I appreciate more than the two of you recently. I feel the need to say thanks for doing your homework, one and two, thanks for the way you bring it to HTS. 

I apologize if I put you on the spot, if this makes you uncomfortable, I don't know what to say..., get over it. Anyway, Dan..., thanks for taking the big book of sound science and breaking that down for those of us who don't have the time, patience and other abilities to wrestle with that amount of information in order to explain our daily experience. You make it sound easy. Bryan without your experience and understanding of sound and science and the listening environment and your willingness to make all of that available to HTS folks is remarkable. 

Great work Men! Thanks

Someday I will try more than improving sound quality and I definitely know who has answers, but today I don't even know what questions to ask. 

By the way I am selling the MIT speaker cables.

Greg


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## S_rangeBrew (Dec 28, 2010)

bpape said:


> And I'm exactly the opposite. The more I can do to avoid modifying the signal, the more I like it. If the speakers, source, processor, and amp are good, you shouldn't have to EQ to get it to sound like what's on the disk. That leaves the room.


I LOVE that idea. But here is my problem. I've read... and read... and read.... and cannot find any definitive texts on how to set up a small room to sound great with an unproccessed signal. As far as I can tell, it's just a matter of doing some basics with absorbing first reflections and slap echos (as I have done) then using diffusers as you suggest. And then moving stuff around with trial and error.



> IMO, EQ is a crutch to be used only when something is left that can't be dealt with any other way - or - when the user deliberately wants something that is not true to the original signal (house curve anyone???)


That's kind of interesting, because people constantly complain about what Audyssey EQ does to their listening experience, and the Audyssey guys claim they are just trying to recreate the movie mastering studio... which is usually an acoustically "dead" room. However, after listening for a while, people often find the Audyssey EQ'ed listening experience to be ultimately superior. Subjective stuff, to be sure. I personally find the idea of taming the almost uncontrollable sub-bass the most intriguing part of electronic EQ.


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## bpape (Sep 14, 2006)

The smaller the space, the harder it is to deal with. The biggest thing is to get the seating, speakers, and sub set up in the right places for the smoothest response, minimal modal interaction, etc. Sure, you may need to add 1 band of EQ but a lot of subs provide that functionality already. I personally would never use EQ on anything but the sub. Not putting extra electronics and processing on my main channels.


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## DanTheMan (Oct 12, 2009)

You're welcome Greg. Thank you for the compliment!

One thing about processing is for sure, it's no substitute for treatment. Personally if I were to design an audio system from scratch in any prebuilt room, I'd start with the speakers(and source components based on needs), then placement, then treatment, and processing last to minimize what can't reasonably fixed otherwise. 

Dan


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## Gregr (Nov 2, 2010)

I'm in agreement with both of you. I heard somebody say a long time ago that to achieve the best possible sound reproduction there should be minimal electronics interfering with the sound and signal path. I have found this to be so true in every instance. 

Lately I've noticed that in the digital realm my computer sound card sounds best perfectly flat on most days. But there are times when I feel I need to tweak the EQ. Maybe its just the equipment has sat idle longer than usual and the speaker cables need to build an internal charge or the system needs to re-acclimate and hours later I am back to return the EQ to flat. But when I do tweak the EQ it is always the lower treble (maybe its just me). Anyway what I want to say about the digital EQ is this digital adjustment do not alter sound quality as making adjustments using an analogue EQ (from the past) did. I'm sure you can see why this might be true (no resistance tweaking etc). 

So now when rangebrew writes about 11.2 processing and Dan refers to EQ adjustments I'm more curious about the result these days.

But I do have a question. Dan, Bryan when you refer to "modal domain" ..., which domain and what modes are you referring to. When you use the term it sounds specific but to me it sounds like a general 
term. Could you give me a reference for the term in the way you are using it.


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## bpape (Sep 14, 2006)

Not sure what you're asking but I think what was referred to was the area in the frequency range where the fundamentals and first couple harmonics of the axial, tangential, and oblique modes exist.


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## DanTheMan (Oct 12, 2009)

The modal region to me is essentially the frequency range where the room modes are so sparse that they dominate the frequency response and essentially act as part of the source and largely effect perceived frequency response. In most rooms this is under 200Hz, but it's not a definite line in the sand. The number of modes actually increase with frequency and they become so populous as to not be problematic at some point called the Schroeder frequency. This is also the region where the ear's integration time and pitch detection time is long, but frequency resolution is very good. That's why I say it's the region you can use and EQ to help--an EQ does nothing for the time domain(in a sense though reducing a peak will reduce the amount of measured ringing b/c rooms and speakers are largely linear devices), but operates in the frequency domain. Our integration time in the bass range is longer than the measurement duration we take. That's not to say that bass decay is unimportant. Tight bass can improve the clarity of everything above it b/c ringing can mask other signals to some degree depending on how big of problem it is. It will also effect the perceived frequency balance. EQing the bass by killing the peaks will tighten the bass and reduce masking.

Other problems with not positioning and treating your room for bass have to do with seat to seat variation and definitely dips and nulls. Boosting nulls can be a very bad thing d/t power consumption and stressing the speaker. Positioning and treating is the only good option and is the start os the ultimate solution.

Dan


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