I got a few acoustic panels - Where should I put them?

Discussion in 'Sound Science' started by noname2020x, Dec 30, 2017.
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  1. amirm
    Come again? Of course I know he sells diffusion products. A bookstore owner who is republican doesn't become democrat because he also sells books about them! I have also seen that video you posted and hence the reason I know about the flaw in that experiment.

    None of this has anything to do with you characterizing his believes as: "So in fact Ethan Winer does believe in full sounding rooms with reflection, but he believes in achieving that with even dispersion." Quote me where he says that. Or anything close to it.

    I posted a picture of his room which shows no diffusion products at all. He is very proud of the sound he gets in that room and has discussed it many times over the years. That again is how I knew to go and dig up his room.

    Ethan is a prolific posters and it is so simple to read his views across literally thousands of posts. Here is one where were both participating in:

    upload_2018-1-2_14-56-22.png

    There is no suggestion to use diffusion. Or believing in a room full of reflections. He is opposed to letting those reflections be there. If it were up to him, he would block them all. As he should given how his hearing has evolved (trained) to hear their effects and consider them something undesirable.

    Note to bigshot: if Ethan is your hero, see how he is also advocating carpet on the floor as I did.
     
  2. amirm
    No, what you have noticed is that I don't back off when someone makes up stuff like what Ethan believes in, and at any case, has no command of the science in this area. Show me authoritative research that demonstrates what I am saying is wrong and I will most definitely accept it. Just claiming that you are right and I am wrong, doesn't make you right.

    Also, you two keep getting personal. I don't have much patience for people who do that at the expense of sharing real knowledge and data.
     
  3. amirm
    You only worry about floor reflection relative to where you sit so a throw rug solves that problem nicely. There is no need to carpet wall to wall here.
     
  4. bigshot
    His living room is very large. In his video, he recommends diffusers for small rooms... like the one we saw the map of at the beginning of this thread. You kind of have to look at the room before you make suggestions. In a small multipurpose room like this, I'd work on primary reflections and probably leave it at that. And with space at a premium, I'd do it with furniture and bookcases. But heck, that's just me.
     
    Last edited: Jan 2, 2018
  5. amirm
    No on both. Watch it again. He says the opposite in the video:

    "I am NOT a fan of diffusers at reflection points. At least NOT in a smaller room. My living room is 16 feet wide and when I replaced the absorbers with diffusers at the side wall reflection points the sound was noticeably worse than with absorption there. Perhaps in a very wide room diffusion be OK but diffusers would have to be pretty far from you ears. Likewise diffusers on front wall do much unless you have dipole that radiate equally front to back.... All domestic rooms need absorption especially at bass frequencies.... ALL acoustic problems can be solved using only absorption. "

    So no, he is not recommending diffusions. Nor does he consider his room large.

    OP's room by the way is an open floor plan. Volume helps immensely to lower the transition point below which you have a modal response. Therefore, his room is much larger than it seems.

    BTW, by quoting Ethan above I am not at all agreeing with him. I am just pointing out that neither one of you have paid attention to any of Ethan's teachings. To wit, have you even been to this web site? Here is what he writes there: http://realtraps.com/art_basics.htm

    upload_2018-1-2_17-44-48.png

    His position could not be more clear than this. As I said, he has been very consistent over the years. It seems neither one of you arguing left and right have bothered to spend any time reading what he has written.

    Instead of spending time here, please spend a few dollars and purchase Dr. Toole's book,
    Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms (Audio Engineering Society Presents) 3rd Edition
    https://www.amazon.com/Sound-Reprod...coding=UTF8&psc=1&refRID=QV67HZM0J8P6B0HE0NGT

    You will learn more about sound reproduction than spending a million hours online.
     
  6. bigshot
    That isn't a small room.
     
  7. amirm
    In domain of acoustics, even the largest home listening rooms are considered "small." For a space to be large, it has to have a transition frequency below 20 Hz as to not have a modal region. OP's room for example has transition frequencies between 150 and 200 Hz (I am guessing on the height).

    To get to a transition frequency of 20 Hz, you need a volume of roughly 157,000 ft^3 or 4400 m^3. Using random example dimensions, it would be a room that is 75 feet by 60 feet and 35 foot high.
     
  8. bigshot
    OK. Substitute the term "a larger small room" for "large room". It really doesn't matter. The issues in Ethan Winer's beautiful "larger small" living room are probably nothing like the issues the OP faces in a combination kitchen and living room that appears to be about 10 x 15. It's all fine. Try diffusion, absorption, rugs on the floor, side reflection points, ceiling reflection points, etc... The only way the OP is going to find out what works is to understand the basic theory involved and experiment and see what works. There are a whole bunch of wild cards that we just don't know... How high is the ceiling? Is the kitchen tiled? Is the roof wallboard or cottage cheese? Where can he drill into the wall to mount stuff? Is there room to shift the listening position a bit backwards or forwards? We can offer specific suggestions and tell him to do it, but they may or may not work depending on his situation. Every room has problems that can be addressed and compromises that have to be made for livability. Balancing those conflicts is what makes a great room.

    Anyway, the OP appears to be gone now. He just wanted a few simple suggestions and it exploded into an argument and a whole bunch of cut and paste technical crap. There is a way to be helpful when someone asks for suggestions and a way to not be helpful at all. Threads like this illustrate that.
     
    Last edited: Jan 3, 2018
  9. amirm
    Once again disdain for audio science is shown in a subforum dedicated to sound science. If you disagree with the research posted, then please post your own. If you don't' have any, then you have no business calling them "crap." It is unprofessional and unhelpful.

    "Probably?" You think he doesn't have modal issues? I guarantee you that it does as does every domestic listening room.

    On where to put an absorber, again, that has specific answers. While there are differing points of view, what matters is whether that answer can be backed by research and controlled listening test. You know, the stuff you are calling "crap."

    The problem here is really commentary by folks like yourself who are not schooled in this science. I suggest spending some energy learning that, instead of making angry posts here. Start with this video and you will become smarter than everyone in your block. :)

     
  10. amirm
    Once again disdain for audio science is shown in a subforum dedicated to sound science. If you disagree with the research posted, then please post your own. If you don't' have any, then you have no business calling them "crap." It is unprofessional and unhelpful.

    "Probably?" You think he doesn't have modal issues? I guarantee you that it does as does every domestic listening room.

    On where to put an absorber, again, that has specific answers. While there are differing points of view, what matters is whether that answer can be backed by research and controlled listening test. You know, the stuff you are calling "crap."

    The problem here is really commentary by folks like yourself who are not schooled in this science. I suggest spending some energy learning that, instead of making angry posts here. Start with this video and you will become smarter than everyone in your block. :)

     
  11. bigshot
    My Floyd is bigger than your Floyd!

    [​IMG]
    when they blow themselves all up like a big red balloon, I can't resist sticking a pin in it.
     
    Last edited: Jan 3, 2018
  12. gregorio
    1. And what do USB cables have to do with "However, there are ALWAYS two sides to this coin." - When clearly "this coin" is referring to room acoustics?
    2. I wasn't ONLY addressing you. ...
    2a. Yes you did, you stated "that is the opposite of what you want to do on walls." but you don't know (any more than the poster you're contradicting) if treating the side reflection points is appropriate or not in this particular case.
    2b. Yes and I stated that was the best advice given up to that point.
    3. I used an analogy with oxygen, what was it that you didn't understand? Oxygen (like reflections) is not bad, on the contrary it's essential, until there's too much and then it's poisonous! I'm not sure why you sometimes take the argumentative approach of: Quoting scientific research either out of context or misresprented/mis-interpreted and then demand other scientific evidence which disproves the research you've effectively mis-quoted? For example, "Modern psychoacoustic research shows side reflections to be absolutely beneficial." - Either that research is seriously flawed, you've misunderstood it or are quoting it out of context. Side reflections are not "absolutely" beneficial, they are relatively beneficial, depending on the desired purpose and what you've got to start with! I have extensively thought of "voices in movies", in fact cinemas, play houses (theatres) and conference centres for example are typically designed to have much drier acoustics than concert halls because the higher amount of reflections which is beneficial to acoustic musical instruments is harmful to speech intelligibility. This acoustic design approach does not appear to contradict the research you're referencing, just your interpretation of it, because with "drier" we're not talking about reflection elimination but reflection reduction relative to say a concert hall. Side reflections are beneficial but only up to a point and you don't know if this particular room and speakers combination exceeds that point!

    I know this isn't your quote but a quote from Ethan but obviously it's not true. There's at least one acoustic problem which obviously cannot be solved by using only absorption, the acoustic problem of a room being too dry/anechoic. Now that's not a problem we're ever going to run into, UNLESS we try to solve all the acoustic problems with absorption! Which is why in commercial music studio control, mix or mastering rooms we tend to use a combination of diffusers and absorption.

    G
     
  13. amirm
    That's like saying we don't know if we put ice cream in front of someone, they will like it! :) Research shows that in controlled experiments, when sidewalls reflections are taken away, there is less preference for sound for vast majority of listeners. In that regard, this is a property of the listener, not the room. So we can make these statements with high confidence that absorbing side reflections will result in worse sound, not better. Based on research of course. Just like we know it is most likely that someone will like ice cream.

    Here is some cut-and-paste "crap" from Dr. Toole's book:

    upload_2018-1-4_10-51-30.png

    Oh, don't jump on the last sentence. If you speak to Dr. Toole in person, he is far, far stronger than that when stating that absorbing side reflections is an error. And exceptions are few and in between.

    Also, there are pages and pages of research in the book. And research from many others which I can fill an entire forum with on this topic. DO NOT go by gut feeling about what reflections do. And certainly don't listen to forum pundits who are just repeating what they have heard on this topic without any research in the field.
     
  14. amirm
    Well then provide the context and research that shows otherwise. For now, as I said, I am happy to provide you with super authoritative research. Yes, it is going to be centered a lot on Dr. Toole and Olive's work dating backing to 1980s but there is work from others too that built on that and augmented it just the same.

    Here is more. From peer reviewed, Journal of AES paper, Loudspeakers and Rooms for Sound Reproduction—A Scientific Review by Dr. Floyd Toole. This is 25 page paper full of research data and listening tests by the author and other researchers. It also has an incredible 75 references to other papers and research. Dr. Toole digs deep into all aspects of room reflections and draws powerful conclusions. Here is one on impact on speech (think of vocals in music and dialog in movies):

    upload_2018-1-4_11-21-15.png

    upload_2018-1-4_11-24-13.png

    Yes, you can have too much reflections. A bare room with hard surfaces everywhere will have too high of an RT60 and needs general absorption to bring that down. Ideal range is between 0.2 and 0.5 seconds (former more for multi-channel, latter for music).

    Side reflections however should not be where you get that absorption based on research. Cover the floor, back wall, side walls elsewhere, etc.
     
  15. gregorio
    1. In a sense.
    2. I'm not advocating that side wall reflections should be "taken away" or that side wall reflections are undesirable, haven't I made that clear? I'm saying that without more information you cannot "safely say" that some reduction in side wall reflections is not beneficial. We know the room is relatively small, has parallel surfaces and is certain to have some issues but we do not know the output of the speakers, the wall materials or the interaction between the two. I agree that in most cases there are places other than the side reflection points which should be given treatment priority but we cannot "safely say" anything without having any idea of the variables at play. Case in point ...
    3. The majority of people probably do like ice cream but you cannot safely say/instruct someone to eat ice cream without being more sure of the variables: Is the person you're giving the ice cream to a diabetic, are they lactose intolerant, does the ice cream contain any nut products, do they have a dental/nerve problem, etc. Your "safely say" could in fact kill someone! You cannot always take specific circumstances/conditions, scientific experiments and apply the results absolutely to all circumstances/conditions.

    G
     
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