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Room treatment

Discussion in 'TAG McLaren Audio Owners' Forum' started by Thunder, Jun 11, 2004.

  1. Thunder

    Thunder
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    Ok, I know this isnt strictly a TMA related question but I know that most of the guys on here are extremely knowledgeable. Here goes; My room is a dedicated AV room, it measures roughly 5m long by just over 3m wide. The front/back and left walls are plastered brickwork. The ceiling and right walls are plasterboard. I had the room TMREQ'd by Ian Heaton and Barry, and although a massive improvement in the bass department I still want to improve it as I find it quite harsh sounding at times, this is probably due to all the bare walls. I have been looking at the Auralex range of studio room treatments that can be found at www.dolphinmusic.co.uk. When Ian originally calibrated my system he told me that the biggest problem was the length modes caused by the solid front and back walls. I was wondering if the application of Auralex foam wedges as mentioned above would help improve the room acoustics? If so, should I apply them to the front or back walls or both? Should I apply them to the entire wall or just the upper half? :confused: I dont mind the way it looks as its a dedicated room and SQ comes first :lesson:
     
  2. deckard

    deckard
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    I use Auralex DST and LENRD bass traps in my room to excellent effect.

    However, to fully tame an axial modal resonance of 68Hz (the predictied 1st modal resonance for your 5m length) you will need to use Venus bass traps placed in the middle of your front and rear walls, probably two panels on each wall. Just bear in mind that these are 12" in thickness, anything less thick simply wont absorb any frequencies at the range your problems lie.
     
  3. Thunder

    Thunder
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    Your prediction of one of my rooms length modes frequency is impressively accurate deckard! But I was also after reigning in some of the harshness in the upper frequencies and I thought an all over wall treatment using the wedges would have accomplished this best? As for bass traps TMREQ has done a pretty good job at eliminating this problem although I will have a look at the product you have recommended out of interest.
     
  4. deckard

    deckard
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    Oh I see! In that case go for it, the wedges/pyramids/DST panels work a treat at mid/high frequencies in terms of taming harshness and improving imaging by means of removing sonic reflections. You need to be slightly careful in applying the treatment all over, as a completely 'dead' acoustic room isn't entirely desirable. Drop an e-mail to Gavin Haverstick at Auralex or fill in one of their online information forms, they're very helpful and they have a new range of domestically appealing panels coming soon too.
     
  5. jolaca

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    Hi, I am also interested on this product. I will like to know if any of you have experience with the difussion products they offer. I want to improve the 3D imaging of my home theater room using some difussion panels at the front stage, but I do not know wich difussor to use. On their web they have 6 different difusion products...Wich one do you recommend and why??

    Thanks in advance.

    Jorge.

    PS: My room is already treated with some absorption material but I will also like some difussion.
     
  6. Martin_M

    Martin_M
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    There is a lot of reading about acoustic room optimalization here.

    Martin
     
  7. deckard

    deckard
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    Most authorities would say a big NO to diffusion on the front stage, you want to absorb those reflections coming of the front wall. To increase spaciousness you may try some diffusion behind the listening position, but not normally directly behind as you want to absorb anything coming back directly behind. What products are you using already Jorge?
     
  8. jolaca

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    Hi Deckiard, thanks for your answer, it makes a lot of sense. However, I have seen some hig-end audio shops and some photos of audio studios that actually had some difussion at the front stage and on the front side walls... it seems that the idea is to combine some difuse reflection with some absorption to make the room seem bigger. But I have also read some comments like yours against this kind of difussion at the front. Any comments any of you experts...Graham, Dr Udo, ...anyone??

    My room features right now:

    - Its dimenssions are not multiples between them, to minimize resonance modes.
    - Wood floor
    - Some absorption panels at the ceiling. Not all, do not want to be too dead.
    - Thin carpet (moqueta in Spanish, sorry my english is so bad) at the walls. Black at the front stage and dark blue at the side and back walls (to optimize projection viewing).

    Maybe I could post a photo to show it to you.

    Thanks again in advance for your answers.
     
  9. Gordon @ Convergent AV

    Gordon @ Convergent AV
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    Joel

    More likely is that they have absorbtion at areas of first reflection on front and rear walls and diffusion at back sides.

    Foam for dealing with bass frequencies have to be very deep due to the wavelengths involved. Generally the best way to deal with uneven bass in a room is to look at moving the sub or your seating rather than sticking something on the wall

    Gordon
     
  10. deckard

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  11. Matt192

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    If you want good bass response then look at a membrance absorber tuned to your problem frequency. It takes up less space and is much more effective than a tube trap or thick foam.

    If you want a bigger soundstage, absorb the reflections off the front wall partially diffuse the first reflection off the side wall to alter the arrival time to between 50 and 110ms and diffuse the back wall with a broadband diffusor. This works well in my experience.

    If you have a low ceiling and a hard floor then these surfaces will also require attention.

    I know some will argue for diffusion on the front wall and I would agree, but at additional cost as diffusors are more expensive than absorbers.
     
  12. jolaca

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    Matt a bigger soundstage is exactly what I want. I do not have problems with bass. Thank you for your advice, that was eaxctly what I was thinking about..to reduce the first reflections in order to defocus the scene a bit to get a 'more open space'. I will investigate over this. Thanks for your answer.
     
  13. lowrider

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    I had a problem around 47hz, placed my player on good supports and no more audible bass problems, I guess acoustical feedback plays a larger role than we give it credit for, try for instance Audioprism Isobearings or Ceraballs or Stillpoints (more expensive)... :lesson:
     
  14. GrahamMG

    GrahamMG
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    Or squash balls cut in half :rotfl: :rotfl: :rotfl: :lesson:
     
  15. lowrider

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    Why not if it works... :p
     
  16. avanzato

    avanzato
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    Sounds like you are describing the 'Early Sound Scattering' technique. A very diffuse front wall with the rest of the room absorbant and heavy bass trapping on the rear wall. I've no idea how well it would work for HT and I've not got the patience or money to make that many diffusers to try out myself. Anyone else want a go?

    On another point RPG say diffusion is not a nearfield solution ie. diffusers should be at around 10ft/3m or further away from the listeners to be effective. In a small room absorbtion works better.
     
  17. Thunder

    Thunder
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    I have now installed some Auralex products in my room and just thought I would let you guys know the results :) The main problem in my room as stated earlier was a harshness to the sound. This meant that at times the volume would have to be reduced because the upper frequencies would make me cringe a little during loud passages in movies and some CD's. Bass control in my room isnt an issue as TMREQ takes care of that side of things and I believe if possible, its better to attenuate the offending modes at source rather than try to absorb them afterwards. Anyway I filled in an Auralex room assesment sheet and diagram (available on their web site) and sent it off. I recieved a prompt and detailed response via e-mail. They recommended multiple foam panels at roughly ear height all around the room as well as on the ceiling and two bass traps in every corner. Because my room is dedicated SQ takes presidence over decor but I still didint want my room looking like a hedgehog. This coupled with the fact that I was skeptical as to the level of benifit the treatment would make, I decided to implement some if not all of the recommended treatment. I concentrated on the screen and rear walls as well as the side walls immediately around the speakers, trying to be inventive in the application of the wedges. They were easy to apply and cut to shape using a sharp carving knife and spraymount glue. Asthetically they actually look quite good, now for the important part: the sound. Well I was very supprised to find the treatment had changed the sound quite a lot. Everything was much less "in your face" and much more neutral sounding, this was especially noticable with CD's. Discs that I had considered top end heavy now sounded really quite good, movies also benefited especially during action sequences. Everything just much more coeherent, with the hole frequency range seeming to gel much better :thumbsup: Its much closer to the type of sound I had heard when visiting the TMA AV room. Anyway I cant recommend these products enough for anyone with similar acoustic prolems they really do make a difference. As a semi-skeptic, I have been turned :clap:
     
  18. Thunder

    Thunder
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    Must appologise for the above spelling and punctuation, but it was done in a hurry.
     

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