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post #3001 of 9564
Quote:
Originally Posted by kbarnes701 View Post

I do not doubt that in a classroom the teacher's dialogue might be rendered more intelligible if reflections are allowed or even encouraged. But this is because the reflections raise the level of the dialogue. As I said, we don't need to do that in playback rooms because we have the volume control as the means of raising the level. If the dialogue is unintelligible because it's not loud enough, then the volume control represents an easy and universal solution.
You're repling in binary terms: intelligible vs unintelligible. I was asking as a matter of degree: improving intelligibility. (assuming you believe there are varying degrees of intelligibility rather than on/of)

If intelligibility can be improved in a classroom, where there is no volume control to reach for, why do you believe that it is not possible and/or not a good idea to have the same as a starting point for a home theatre?

Gear mentioned in this thread:

post #3002 of 9564
Quote:
Originally Posted by AustinJerry View Post

I'm trying, Jim! rolleyes.gif I'm also trying to avoid false steps that cost money.

I meant, someone elses biggrin.gif
post #3003 of 9564

Need opinions, please.  Would this type of ceiling fan blade reduce/eliminate reflections?

 

http://www.hunterfan.com/Products/Ceiling_Fans/Caribbean_Breeze-21648/

post #3004 of 9564
Quote:
Originally Posted by jevansoh View Post

Decreasing your noise floor and increasing your dynamic range is imperative to good speech intelligibility.
No disagreement there. But once you've done whatever you can to reduce the noise floor and maximize dynamic range, should we stop trying to improve intelligibility (because other tweaks make too little of a difference) or can intelligibility be further improved? Knowing what we do about our how our human hearing works, are there other things we can play with (e.g., decay time, reflections) to make dialogue more intelligible?
post #3005 of 9564
Quote:
Originally Posted by AustinJerry View Post

Need opinions, please.  Would this type of ceiling fan blade reduce/eliminate reflections?

http://www.hunterfan.com/Products/Ceiling_Fans/Caribbean_Breeze-21648/

Perhaps LESS than a wooden blade fan.

I think the best solution is to have the fan moved to somewhere behind the listening spot.

You could try wrapping each fan blade in something that absorbs. May not push air like it did before though.
post #3006 of 9564
I can't imagine that any fan blade would reduce the reflections enough to matter, since there is matter there.
post #3007 of 9564
Quote:
Originally Posted by RickD1225 View Post

I can't imagine that any fan blade would reduce the reflections enough to matter, since there is matter there.

You may be correct, but the current blades are a smooth, hard wood which is highly reflective. The blades on the fan in the link are not smooth, so there is likely to be a certain degree of diffusion, as opposed to pure reflection. Unfortunately, there is no way to know without trying it, and $250 plus the trouble to install it is not trivial.
post #3008 of 9564
Quote:
Originally Posted by sdurani View Post

You're repling in binary terms: intelligible vs unintelligible. I was asking as a matter of degree: improving intelligibility. (assuming you believe there are varying degrees of intelligibility rather than on/of)

If intelligibility can be improved in a classroom, where there is no volume control to reach for, why do you believe that it is not possible and/or not a good idea to have the same as a starting point for a home theatre?
Not Keith, but I would not rule out that acoustics can be altered in homes to improve intelligibility. The classroom situation has two forms of acoustics at play: one being early, hard surface (specular) reflections that reinforce the direct path within a short time so that it fuses and improves the apparent loudness of the source over the background noise; and reflections that occur later in time that in effect add to the background noise. We want more of the former, and less of the latter in the "live human speaker" situation.

At home, I'd argue we're not particularly interested in having either. If a home has excess early reflections, they do not result in a change in S/N because the speaker calibration process will take the reflected energy into account. These reflections may, however, color the sound or alter the imaging in undesirable ways. If so, the user can safely opt to eliminate them with appropriate treatment options without fear of degrading intelligibility, unlike the classroom case.

Later reflections can also add to the calibration noise SPL, but not in ways that improve intelligibility. These are best treated to diminish their contribution. This would also be true for the classroom.
post #3009 of 9564
Quote:
Originally Posted by jevansoh View Post

The most common problem relating to dialog intelligibility in my opinion has less to do with reflections than one may think and a lot more to do with available dynamic range which is hindered in most residential living spaces by a high noise floor.
Noise floor is a huge factor.

One other issue that we do not discuss much around here is poor frequency response of the center speaker (maybe we optimistically assume REW will find it and help us fix it wink.gif).

Even a really nice speaker positioned on top of a big TV or, even worse, inside a cabinet, can goose the mid-bass or add strong resonances, and this really hurts intelligibility. The higher bass may fool the SPL meter, causing the mid/treble to be set too low. Or it may sound muddy and inarticulate regardless of how loud it is. These are simple problems to create, but not so simple to fix unless willing to make physical changes.
post #3010 of 9564
Quote:
Originally Posted by Roger Dressler View Post

Not Keith, but I would not rule out that acoustics can be altered in homes to improve intelligibility. The classroom situation has two forms of acoustics at play: one being early, hard surface (specular) reflections that reinforce the direct path within a short time so that it fuses and improves the apparent loudness of the source over the background noise; and reflections that occur later in time that in effect add to the background noise. We want more of the former, and less of the latter in the "live human speaker" situation.

Please define "short time".
post #3011 of 9564
Quote:
Originally Posted by sdurani View Post

Quote:
Originally Posted by kbarnes701 View Post

I do not doubt that in a classroom the teacher's dialogue might be rendered more intelligible if reflections are allowed or even encouraged. But this is because the reflections raise the level of the dialogue. As I said, we don't need to do that in playback rooms because we have the volume control as the means of raising the level. If the dialogue is unintelligible because it's not loud enough, then the volume control represents an easy and universal solution.
You're repling in binary terms: intelligible vs unintelligible. I was asking as a matter of degree: improving intelligibility. (assuming you believe there are varying degrees of intelligibility rather than on/of)

If intelligibility can be improved in a classroom, where there is no volume control to reach for, why do you believe that it is not possible and/or not a good idea to have the same as a starting point for a home theatre?

 

You make, as always, good points there Sanjay, but you did not address the other points I raised in my earlier post. 

 

I agree that it is not black and white and that it is possible that speech intelligibility may be ameliorated by the acoustic environment, even in a HT. My issue is with those who say that such acoustic manipulation via reflections is required for speech intelligibility and that the elimination of reflections must therefore, of necessity, reduce dialogue intelligibility. My headphones example gives lie to this.

 

I also question the comparison between a classroom and a HT. One is a sound creation space and the other is a sound reproduction space and I believe they are two very different things. In a classroom there are likely to be no acoustic treatments at all and there is certainly no 'volume control' with which to raise the SPL of the speaker. This is totally different from the environment of a HT room and I am always wary when someone tries to conflate the two.

 

I would also say that if "improving intelligibility" is the aim, then, by definition, intelligibility is not as good as it should be. Why? In a treated room, with careful and salient speaker positioning, system setup etc, why are people finding dialogue difficult to understand?  I have no such issues at all. Jason has reported he has no such issues at all. Of course, I do agree that some people have dialogue intelligibility issues -- what I am saying is that they need to address the 'why' first and then treat the root cause. I have tried to eliminate as many reflections from my HT room as I can (movies only remember), for reasons we all know, and I have to say that I have zero issues with dialogue intelligibility. This would tell me that the solution to dialogue intelligibility, or to improving it if it is lacking, is not just added reflections ('good' or 'bad') in my case. Similarly, those listening with headphones will also be listening in an environment that is 100% lacking in reflections of any type and I have not heard people say that they cannot understand dialogue when listening with headphones - in fact they usually say the opposite IME. 

post #3012 of 9564
Quote:
Originally Posted by sdurani View Post

Quote:
Originally Posted by jevansoh View Post

Decreasing your noise floor and increasing your dynamic range is imperative to good speech intelligibility.
No disagreement there. But once you've done whatever you can to reduce the noise floor and maximize dynamic range, should we stop trying to improve intelligibility (because other tweaks make too little of a difference) or can intelligibility be further improved? Knowing what we do about our how our human hearing works, are there other things we can play with (e.g., decay time, reflections) to make dialogue more intelligible?

 

Sanjay, you have repeated twice in recent posts that you feel there is a need to "improve intelligibility" or to "make dialogue more intelligible". This would suggest that dialogue is lacking in intelligibility to start with (or it clearly couldn't be improved'). But what about those of us who do not find that dialogue intelligibility requires any improvement at all? If I can clearly hear every word that is spoken, what need for improvement is there?  And given that I have no assistance from 'good' reflections, what is the explanation for this dialogue intelligibility that I have?

 

I am all for using any and every tool in the box in order to get the best sound possible, and it may well be that using 'good' reflections can aid in dialogue intelligibility, along with many other measures. Where I take exception is when someone (not you) keeps pushing the concept that these 'good' reflections are an integral/essential part of clear dialogue. And especially when they use hilarious mumbo-jumbo in an attempt to support the view.

post #3013 of 9564
Quote:
Originally Posted by kbarnes701 View Post

Sanjay, you have repeated twice in recent posts that you feel there is a need to "improve intelligibility" or to "make dialogue more intelligible". This would suggest that dialogue is lacking in intelligibility to start with (or it clearly couldn't be improved'). But what about those of us who do not find that dialogue intelligibility requires any improvement at all? If I can clearly hear every word that is spoken, what need for improvement is there?  And given that I have no assistance from 'good' reflections, what is the explanation for this dialogue intelligibility that I have?

I am all for using any and every tool in the box in order to get the best sound possible, and it may well be that using 'good' reflections can aid in dialogue intelligibility, along with many other measures. Where I take exception is when someone (not you) keeps pushing the concept that these 'good' reflections are an integral/essential part of clear dialogue. And especially when they use hilarious mumbo-jumbo in an attempt to support the view.

Interesting topic.

What I seem to be getting from this conversation is this.

The improved intelligibility caused by early reflections seems to be so mainly because of the gain given to them and the brain fusing the direct and early reflections together. As has been pointed out already, in a amplified speaker system, improved gain isnt necessary given provided amplification. Some seem to claim that early reflections gain you improved intelligibility in an amplified system, but omitting the context that these findings were derived from.

In an home audio system, I cant see how fused early reflections from the room can be an improvement in hearing the recording over hearing the recording without these room reflections. In my experience, the more I remove the room from the first 20ms of the time domain, the better it sounds.

So I have basically some of the same questions as you.
post #3014 of 9564
Quote:
Originally Posted by jim19611961 View Post

Quote:
Originally Posted by kbarnes701 View Post

Sanjay, you have repeated twice in recent posts that you feel there is a need to "improve intelligibility" or to "make dialogue more intelligible". This would suggest that dialogue is lacking in intelligibility to start with (or it clearly couldn't be improved'). But what about those of us who do not find that dialogue intelligibility requires any improvement at all? If I can clearly hear every word that is spoken, what need for improvement is there?  And given that I have no assistance from 'good' reflections, what is the explanation for this dialogue intelligibility that I have?

I am all for using any and every tool in the box in order to get the best sound possible, and it may well be that using 'good' reflections can aid in dialogue intelligibility, along with many other measures. Where I take exception is when someone (not you) keeps pushing the concept that these 'good' reflections are an integral/essential part of clear dialogue. And especially when they use hilarious mumbo-jumbo in an attempt to support the view.

Interesting topic.

What I seem to be getting from this conversation is this.

The improved intelligibility caused by early reflections seems to be so mainly because of the gain given to them and the brain fusing the direct and early reflections together. As has been pointed out already, in a amplified speaker system, improved gain isnt necessary given provided amplification. Some seem to claim that early reflections gain you improved intelligibility in an amplified system, but omitting the context that these findings were derived from.

 

A succinct summary of what I have been trying to convey, Jim. Roger also put it very well too IMO, and with great authority.

 

Quote:
In an home audio system, I cant see how fused early reflections from the room can be an improvement in hearing the recording over hearing the recording without these room reflections. In my experience, the more I remove the room from the first 20ms of the time domain, the better it sounds.

So I have basically some of the same questions as you.

 

That has been exactly my own experience too. When my room was untreated, I did sometimes struggle with dialogue intelligibility. I read somewhere on AVS that some people, whose judgement I respect, sometimes attributed the lack of clarity of dialogue to reflected sound 'interfering' with the direct sound from the speaker. I had already decided to treat my room at some point, but this was a catalyst for me so I set about trying to learn what treatments I would need. I took advice from Bryan Pape at GIK Acoustics and from F. Alton Everest's book, 'The Master handbook of Acoustics' and, of course, from anyone on these threads who would help me (which was many).  

 

Along with learning to use REW, I eventually added significant treatments to the room and guess what? Just as you say, the more I removed the room from the first 20ms of the time domain, the better it sounded. I also noted that whereas my typical (close to reference) listening level on the MV had been -9dB, it was now typically -6dB. A full 3dB of energy had been removed from the room - all of it unwanted (by me at least). I now have a room that some might describe as 'dead' but which I prefer to describe as 'inert' and the sound is fabulous. And, to the point, dialogue intelligibility is just never an issue. 

 

Of course, I only use my HT for movies, as I have mentioned often, and I may well feel differently if I wanted a dual-purpose movie/music room. But, IMO, all the ambience and spaciousness etc is already recorded into the soundtracks and is capably reproduced by my 5.1/7.1 system. I am transported fully to the environment the sound mixer intended, whether it be a vast open outdoor space, a large, echoey indoor space, a 70's discoteque, an intimate interior space or whatever. It is truly wonderful to hear all of these different environments, often in the same movie, in my physically small room. I have made the walls disappear and I am hearing much more of the speakers themselves.

 

I fully accept that this may not be what everyone wants, but it is what I want and I have become convinced that a NE room is just the ticket for me. It may be a hangover from the numerous hours I have spent in small editing suites when finalising the soundtracks for the radio and cinema commercials I used to produce as part of my work - I was always transfixed by the sound the guys in those suites enjoyed, and the one characteristic they all shared was a more or less complete lack of reflections. It is also worth considering that in commercials, the dialogue is often (usually) the most important single element in the whole soundtrack, so dialogue intelligibility was of paramount importance to us - yet we achieved this absolutely without the aid of any reflections in the editing environment. 

post #3015 of 9564
Quote:
Originally Posted by kbarnes701 View Post

A succinct summary of what I have been trying to convey, Jim. Roger also put it very well too IMO, and with great authority.


That has been exactly my own experience too. When my room was untreated, I did sometimes struggle with dialogue intelligibility. I read somewhere on AVS that some people, whose judgement I respect, sometimes attributed the lack of clarity of dialogue to reflected sound 'interfering' with the direct sound from the speaker. I had already decided to treat my room at some point, but this was a catalyst for me so I set about trying to learn what treatments I would need. I took advice from Bryan Pape at GIK Acoustics and from F. Alton Everest's book, 'The Master handbook of Acoustics' and, of course, from anyone on these threads who would help me (which was many).  

Along with learning to use REW, I eventually added significant treatments to the room and guess what? Just as you say, the more I removed the room from the first 20ms of the time domain, the better it sounded. I also noted that whereas my typical (close to reference) listening level on the MV had been -9dB, it was now typically -6dB. A full 3dB of energy had been removed from the room - all of it unwanted (by me at least). I now have a room that some might describe as 'dead' but which I prefer to describe as 'inert' and the sound is fabulous. And, to the point, dialogue intelligibility is just never an issue. 

Of course, I only use my HT for movies, as I have mentioned often, and I may well feel differently if I wanted a dual-purpose movie/music room. But, IMO, all the ambience and spaciousness etc is already recorded into the soundtracks and is capably reproduced by my 5.1/7.1 system. I am transported fully to the environment the sound mixer intended, whether it be a vast open outdoor space, a large, echoey indoor space, a 70's discoteque, an intimate interior space or whatever. It is truly wonderful to hear all of these different environments, often in the same movie, in my physically small room. I have made the walls disappear and I am hearing much more of the speakers themselves.

I fully accept that this may not be what everyone wants, but it is what I want and I have become convinced that a NE room is just the ticket for me. It may be a hangover from the numerous hours I have spent in small editing suites when finalising the soundtracks for the radio and cinema commercials I used to produce as part of my work - I was always transfixed by the sound the guys in those suites enjoyed, and the one characteristic they all shared was a more or less complete lack of reflections. It is also worth considering that in commercials, the dialogue is often (usually) the most important single element in the whole soundtrack, so dialogue intelligibility was of paramount importance to us - yet we achieved this absolutely without the aid of any reflections in the editing environment. 

If I was a movie only guy and had a 5.1/7.1/xx.1 system, I would be tempted to remove all the reflections period (up to 20ms and well beyond) because as you say, the movie tracks themselves provide the ambiance needed so the room doesnt need to provide them.

Being an 2 channel audio only guy though, except perhaps in live recordings, a dead room sounds very dead indeed. And so you have to get creative in order to reintroduce reflections back into the listening experience in the 20-30ms range.
post #3016 of 9564
Quote:
Originally Posted by jim19611961 View Post

If I was a movie only guy and had a 5.1/7.1/xx.1 system, I would be tempted to remove all the reflections period (up to 20ms and well beyond) because as you say, the movie tracks themselves provide the ambiance needed so the room doesnt need to provide them.

Being an 2 channel audio only guy though, except perhaps in live recordings, a dead room sounds very dead indeed. And so you have to get creative in order to reintroduce reflections back into the listening experience in the 20-30ms range.

 

Fully agreed. I am also a 2-channel audio guy and have my stereo setup in a different room. If I used my HT for both music and movies, as many do, I would probably take a very different view. I’d be happy to remove all reflections, period. I am not quite there yet :)

post #3017 of 9564
Quote:
Originally Posted by kbarnes701 View Post

Fully agreed. I am also a 2-channel audio guy and have my stereo setup in a different room. If I used my HT for both music and movies, as many do, I would probably take a very different view. I’d be happy to remove all reflections, period. I am not quite there yet smile.gif

How do you address reflections in your 2 ch audio setup?
post #3018 of 9564
Quote:
Originally Posted by jevansoh View Post

RT60 is used in Large Acoustical Spaces and does not apply to our types of rooms as we don't have a reverberant field.
Actually they do. The whole thread on GS and the one on AVS was to settle that argument. Please take the time to read it. The misconceptions here was created by misreading of a pargraph or two in Davis' and Toole's books. So that we don't repeat it all here, start at the beginning of the thread and move forward: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb.html. Small rooms have reverberant fields. It simply is the case that the starting frequency where that occurs is higher than larger rooms. The math says that. Countless references that I provided in that post say the same thing. Take a look at the partial differential equation for wave propegation and show me where there is a "small" or "big room" discontinuity in there. You won't find any because it does not exist. Reverberant field comes into existence due to modal overlap which is both frequency and volume dependent. If volume is small, the frequency simply goes up for the equiv. level of overlap and hence randomness. I compute all of these parameters in the above post and show how it works just the same in small rooms. Extensive references are provided a the end of the post so I am not just expressing an opinion here.

If you want a reader's digest of the thread, here are some key posts:
http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb.html#post8849404
http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-3.html#post8850544
On misreading Davis' text: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-5.html#post8854266
See quote inn red where Davis' uses RT60 himself: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-8.html#post8858079
One of the claims made to back this misstatement is that small rooms have no "critical distance." See this post from research paper showing critical distance: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-8.html#post8858277
More on actual critical distance measurements form published reports: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-9.html#post8860493
Me measuring critical distance for my room: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-10.html#post8863326
Zooming into where this misconceptions started: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-10.html#post8863901
Addressing both Dr. Toole's and Davis' often quoted lines: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-11.html#post8865993

And of course the final link I provided which comprehensively dealt with this point: http://www.gearslutz.com/board/studio-building-acoustics/821073-can-small-rooms-have-real-reverb-14.html#post8887203
Quote:
Not everyone speaks in a monotonous tone all at the same SPL. I cannot believe that anyone would believe that human speech is 60db at 1 meter. This makes no sense.
Nothing about what I said had to do with everyone speaking at the same level. The 60 dB number is an average that is often used for the level of human speech. An average does not have to be the same as every value used to compute it! The point is not material anyway. The reference to speech as 60 dB is used to find an explanation for why Sabine went after measuring 60 dB decline in reverberation level. As I explained to Roger, this may have been a justification after the fact. There is no other explanation as to why 60 was the magic number. It matters not anyway. We can pick any other number and indeed, we do in listening spaces, with values as low as 20 dB and extrapolating to 60.
Quote:
So much of this information is wrong and contested by individuals with much higher and more specific credentials than myself, but how exactly does any of this "mis" information apply to anyone's question here or help them in any way??

--J
Well, they all voiced their opinion on Gearslutz and ultimately the dust settled with everyone backing off when I post that final one above. If you think they didn't make an argument that you would, by all means create a new thread and I will address it. But I am pretty sure no stone was left unturned.

Answering your good question, it is simple. It would be great to know whether any room is too little or too much absorption. We are talking about overall levels here and not specific targeted use of absorption (e.g. for dealing with reflections). When have you made your room too dead or left it too live? That question can be answered using an experienced ear (or even your eyes if you know what to look for). If you don't have one, and I suspect many do not, or want a quantitative answer, then you use RT60 measurement using filtering at 500 to 1000 Hz. The "good range" is between 0.2 to 0.5 or so. Don't worry about too much accuracy there and chasing precise numbers. We are looking at gross values here. If you are at 0.1 or smaller for example, you have a dead room. And if it is 1.0, it is very live. Live rooms can be enjoyable but may be harder to understand speech in them. Dead rooms are good for speech but won't sound as enjoyable. Since our rooms are for mixed use content, the stated range was developed as a good rule of thumb. You don't need to understand any of the math and theory to understand how to use this simple test that is readily available in REW.
post #3019 of 9564
Quote:
Originally Posted by jim19611961 View Post

Quote:
Originally Posted by kbarnes701 View Post

Fully agreed. I am also a 2-channel audio guy and have my stereo setup in a different room. If I used my HT for both music and movies, as many do, I would probably take a very different view. I’d be happy to remove all reflections, period. I am not quite there yet smile.gif

How do you address reflections in your 2 ch audio setup?

 

I was hoping you wouldn't ask that smile.gif.

 

My 2-ch room is my living room. In it I am using equipment I have had for many years. My speakers, for example, and my Class A two channel amp are at least 20 years old. My CD player is a Naim Audio unit that must be approaching that age too. The room is furnished 'well', by which I mean there are thick drapes over the two windows which dominate the end walls (the drapes more or less over the entire walls, width-wise and floor to ceiling), plus two very large sofas plus a thick carpet which also has a large, thick area rug over about one third of the floor space. The walls are dryrock sheeting over concrete blocks and there is a gap of about 2 inches between the dryrock and the concrete blocks. There is then a cavity of about 4 inches and the outside of the house is red brick. This is pretty normal UK-style house construction for relatively new homes (ours is 16 years old). There are no dedicated acoustic treatments as neither myself nor Mrs Keith want them in the main living space. 

 

My musical tastes are fairly catholic, but I tend to favour fairly small jazz combos from the 1953 to 1966 era, plus Blues from 1930 or so onwards, with some 60's soul music for good measure, a fair bit of jazz fusion from the 70s and 80s and the occasional rock and punk bands. I don't really go in for much classical music or for big band jazz, although I have some of both in my collection. I am currently listening to, and enjoying opera sopranos though, although only in excerpts -- I doubt if I could do a whole opera. 

 

I believe that I know the content and the equipment so well that I may have learned to 'listen through' the room, but that is speculation. If I had a dedicated 'music room' I would wish to go down the road of learning how best to treat it to optimise it for music. I made the decision to keep the HT for movies only simply because when listening to music I prefer to relax in a regular domestic environment rather than listen in a room that has really been set up for movies (eg a huge screen on the wall facing the reclining cinema seats and acoustic panels everywhere). The HT room has been designed to be used in the dark, for obvious reasons, so I am not at all concerned with how it looks - but that most definitely does not apply to the rooms in the rest of the house, which are all very 'designed' (my background is partially in the design world). 

 

Whenever I comment here on AVS, I am always referring to HT rooms used for movies unless I specifically say otherwise, as in this post. I perhaps ought to add that caveat to my signature to avoid any potential confusion.

post #3020 of 9564
Quote:
Originally Posted by kbarnes701 View Post

I was hoping you wouldn't ask that smile.gif
.

My 2-ch room is my living room. In it I am using equipment I have had for many years. My speakers, for example, and my Class A two channel amp are at least 20 years old. My CD player is a Naim Audio unit that must be approaching that age too. The room is furnished 'well', by which I mean there are thick drapes over the two windows which dominate the end walls (the drapes more or less over the entire walls, width-wise and floor to ceiling), plus two very large sofas plus a thick carpet which also has a large, thick area rug over about one third of the floor space. The walls are dryrock sheeting over concrete blocks and there is a gap of about 2 inches between the dryrock and the concrete blocks. There is then a cavity of about 4 inches and the outside of the house is red brick. This is pretty normal UK-style house construction for relatively new homes (ours is 16 years old). There are no dedicated acoustic treatments as neither myself nor Mrs Keith want them in the main living space. 

My musical tastes are fairly catholic, but I tend to favour fairly small jazz combos from the 1953 to 1966 era, plus Blues from 1930 or so onwards, with some 60's soul music for good measure, a fair bit of jazz fusion from the 70s and 80s and the occasional rock and punk bands. I don't really go in for much classical music or for big band jazz, although I have some of both in my collection. I am currently listening to, and enjoying opera sopranos though, although only in excerpts -- I doubt if I could do a whole opera. 

I believe that I know the content and the equipment so well that I may have learned to 'listen through' the room, but that is speculation. If I had a dedicated 'music room' I would wish to go down the road of learning how best to treat it to optimise it for music. I made the decision to keep the HT for movies only simply because when listening to music I prefer to relax in a regular domestic environment rather than listen in a room that has really been set up for movies (eg a huge screen on the wall facing the reclining cinema seats and acoustic panels everywhere). The HT room has been designed to be used in the dark, for obvious reasons, so I am not at all concerned with how it looks - but that most definitely does not apply to the rooms in the rest of the house, which are all very 'designed' (my background is partially in the design world). 

Whenever I comment here on AVS, I am always referring to HT rooms used for movies unless I specifically say otherwise, as in this post. I perhaps ought to add that caveat to my signature to avoid any potential confusion.

No scorn for having a basically untreated audio room. Based on your apparent knowledge though, you could make it a lot better sounds like smile.gif
post #3021 of 9564
Quote:
Originally Posted by markus767 View Post

Please define "short time".
~30 ms or less.
post #3022 of 9564
Quote:
Originally Posted by amirm View Post


Answering your good question, it is simple. It would be great to know whether any room is too little or too much absorption. We are talking about overall levels here and not specific targeted use of absorption (e.g. for dealing with reflections). When have you made your room too dead or left it too live? That question can be answered using an experienced ear (or even your eyes if you know what to look for). If you don't have one, and I suspect many do not, or want a quantitative answer, then you use RT60 measurement using filtering at 500 to 1000 Hz. The "good range" is between 0.2 to 0.5 or so. Don't worry about too much accuracy there and chasing precise numbers. We are looking at gross values here. If you are at 0.1 or smaller for example, you have a dead room. And if it is 1.0, it is very live. Live rooms can be enjoyable but may be harder to understand speech in them. Dead rooms are good for speech but won't sound as enjoyable. Since our rooms are for mixed use content, the stated range was developed as a good rule of thumb. You don't need to understand any of the math and theory to understand how to use this simple test that is readily available in REW.

 

Amir,

 

This thread is intended to give entry-level REW users instruction.  It would be helpful if you assumed the majority of your audience fell into the beginner category and if you provided some instructions on how to generate the REW graphs you reference.  Unfortunately, the REW Help file is rarely useful, at least not for me.

 

So, please help me interpret the REW R60 graph below.  What should we be looking at, TOPT, EDT, T20 or T30?  What settings should be checked in the Control window?  Is the proper filtering applied?  Do I fall in the 0.2 to 0.5 range?

 

 

 

 

Thanks.

post #3023 of 9564
Quote:
Originally Posted by AustinJerry View Post

Amir,

This thread is intended to give entry-level REW users instruction.  It would be helpful if you assumed the majority of your audience fell into the beginner category and if you provided some instructions on how to generate the REW graphs you reference.  Unfortunately, the REW Help file is rarely useful, at least not for me.

So, please help me interpret the REW R60 graph below.  What should we be looking at, TOPT, EDT, T20 or T30?  What settings should be checked in the Control window?  Is the proper filtering applied?  Do I fall in the 0.2 to 0.5 range?






Thanks.

Why only showing 500hz-1K Jerry?
post #3024 of 9564
Quote:
Originally Posted by jim19611961 View Post

Why only showing 500hz-1K Jerry?

As I admitted in my original post, Jim, I have no idea what I am doing with this graph. But if you read Amir's post, he recommends filtering 500-1000Hz, doesn't he? If you are familiar with the REW RT60 graph, can you provide step-by-step instructions for us?
post #3025 of 9564
Quote:
Originally Posted by AustinJerry View Post

Amir,This thread is intended to give entry-level REW users instruction.  It would be helpful if you assumed the majority of your audience fell into the beginner category and if you provided some instructions on how to generate the REW graphs you reference.  Unfortunately, the REW Help file is rarely useful, at least not for me.
Agreed smile.gif.
Quote:
So, please help me interpret the REW R60 graph below.  What should we be looking at, TOPT, EDT, T20 or T30?  What settings should be checked in the Control window?  Is the proper filtering applied?  Do I fall in the 0.2 to 0.5 range?

For a quick answer, ignore everything but Topt. Uncheck all the others so that you are only seeing that one line. Then either zoom into 500 to 1000 as you did, or just look at the column that corresponds do that range of frequencies. Assuming the green in your graph is Topt, then you are in good shape at around 0.55.

Another bonus from this measurement is that it tells you how much headroom you have in adding more absorption (my terminology). Say you thought you should add two more panels to your room for whatever reason. Since you are pretty far from 0.2, you could do that even without doing the math, knowing that your room will not be "dead." If on the other hand you were down at 0.15, I would caution in you adding more absorption. Would suggest removing some others before adding the targeted ones.
post #3026 of 9564
So the cookbook answer is:

1. Click on the "RT60" Tab in REW.
2. Uncheck all boxes at the bottom except for Topt (which should be the first box in green).
3. Eyeball the 500 to 1000 Hz range of frequencies on the bottom and read the value on the graph. You want to aim for 0.2 to 0.5 there.
post #3027 of 9564
Quote:
Originally Posted by AustinJerry View Post

As I admitted in my original post, Jim, I have no idea what I am doing with this graph. But if you read Amir's post, he recommends filtering 500-1000Hz, doesn't he? If you are familiar with the REW RT60 graph, can you provide step-by-step instructions for us?




RT60 isnt one of those graphs I use much. My feeling is everything you need to know can be derived from FR, ETC, Decay and Waterfalls. But the above is how I usually see other people display their RT60 when I see them, which is fairly often.
Edited by jim19611961 - 5/27/13 at 2:36pm
post #3028 of 9564
And to contrast with Jerry's room, he is the measurements for out very large, and very hard surfaces living room (almost very little absorption);

i-qszb9dm-L.png

In this room, we have a hard time understanding each other if not talking within a few feet. And listening to speech on TV is challenging. We have to turn up the level to uncomfortable levels. Plan to add more "absorption" in the form of furnishings once my wife decides what she wants in the room smile.gif.
post #3029 of 9564
Quote:
Originally Posted by jim19611961 View Post

No scorn for having a basically untreated audio room. Based on your apparent knowledge though, you could make it a lot better sounds like smile.gif

 

I could probably do that, but there is no real incentive for me ATM. All my energies have been concentrated on the HT room. Movies have always been a huge passion of mine, going back to when I was 5 or 6 years old and my mother used to take me to the movies (she was a passionate movie fan too). I started down the audio road just so I could see and hear movies the way their creators intended - HT as such was never meant to be a hobby in itself, but it has sort of evolved that way.  As I have gotten older, my interest has switched from music to movies and the latter take up most of the time I am prepared to dedicate to my hobbies. These days, music plays a part in my life but it has more or a 'background role' IYKWIM. Having said all that, I enjoy learning more about acoustics and enjoy the time I spend on AVS - it has developed into an additional worthwhile hobby in its own right.

post #3030 of 9564
Quote:
Originally Posted by AustinJerry View Post

Quote:
Originally Posted by jim19611961 View Post

Why only showing 500hz-1K Jerry?

As I admitted in my original post, Jim, I have no idea what I am doing with this graph. But if you read Amir's post, he recommends filtering 500-1000Hz, doesn't he? If you are familiar with the REW RT60 graph, can you provide step-by-step instructions for us?

 

+1. I'd love that too.

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