Bass Trap question

Discussion in 'Home Theater Projects' started by Blaine_M, Feb 13, 2006.

  1. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    I'm looking to build a couple of bass traps this weekend. Most of the DIY sites I've seen always show them round. My question is do they need to be round? Can I make them square instead, or is there a reason they are round?

    Thanks......
     
  2. ThomasW

    ThomasW Cinematographer

    Joined:
    Nov 6, 1999
    Messages:
    2,282
    Likes Received:
    0
  3. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    I found this web site for a company that makes them square.....

    http://www.realtraps.com/products.htm

    I was hoping to be able to make them square and stuff them with fiberglass insulation, similar to the DIY round tubes I've seen, but no hollow space in the middle. Similar to what is at this site, but I won't have the foam...

    http://www.gr-research.com/foam.htm
     
  4. ThomasW

    ThomasW Cinematographer

    Joined:
    Nov 6, 1999
    Messages:
    2,282
    Likes Received:
    0
    Although not as people friendly as foam, fiberglass absorbs low frequencies better. It's all about how deep the traps are for how low the frequencies they absorb, the shape is secondary.
     
  5. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,865
    Likes Received:
    0
    I think the resonator type traps are round because you can buy tubes that are round already, then put stuffing in them or fill them partially with sand or whatever.

    I've seen PVC used for this and sonotubes. Just easier to construct.

    Square traps do the same thing but could be harder to construct to be tight and rigid like you can with a cylinder.

    You don't want there to be air cracks at the seams of the cube shaped traps since that will reduce their effectiveness. You also want to sort of "Pack" fiberglass so it's not loose, and this is easier with a cylinder shape and "wrapping" it with hog wire or twine.

    As far as effectiveness, the shapes do the same thing.

    I would focus on "height", and "width" and I think the general rule is for controlling deeper frequencies... Make it BIGGER.
     
  6. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    I've decided to go ahead with round traps, Unfortunately I'm limited to about a 15 inch diameter and about 4 feet tall..............I'll be starting on them Monday, have today and Monday off.....finishing the fabric on my wall panels today. I'll try and stuff the fiberglass in there fairly tight.
     
  7. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,865
    Likes Received:
    0
    15"D 4 feet high traps should definitely make a noticeable change.

    I made four similar size traps and it reduced the "DIPS" of my room's frequency response by 2db and pretty much altered the "sound" of the bass making it cleaner.

    I believe that Bass Traps really do things that parametric equalizers can not.

    It's no easy work though. [​IMG] Lots of time...
     
  8. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    I made some wall panels and put them on the walls, my wife hates them and keeps threatening to take them down! Oh well, it's a battle hopefully I can win!
     
  9. Chris Tsutsui

    Chris Tsutsui Screenwriter

    Joined:
    Feb 1, 2002
    Messages:
    1,865
    Likes Received:
    0
    Yeah, the WAF or SAF is extremely low for bass traps, HH resonators, and diffusors. [​IMG]

    If we left it up to the significant others to do our shopping we'd all have wall mounted plasmas with little or no component rack, and a well concealed Bose system. heh

    Actually I think my significant other only wants a 27" CRT, cable box, and a VHS/DVD combo player. If she had a choice she'd probably want it in an oak cabinet with cabinet doors to hide the TV.

    Wait a second... she doesn't even watch tv all that much... :/
     
  10. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    Ok, I got my traps done....now what difference should I be noticing?

    [​IMG]
     
  11. ThomasW

    ThomasW Cinematographer

    Joined:
    Nov 6, 1999
    Messages:
    2,282
    Likes Received:
    0
    Tigher bass with better definition/detail, depending on the quality of the sub itself.
     
  12. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    The sound is a tad cleaner, that's about the only way I can describe it with my limited vocabulary......maybe that's the 'tighter bass'......? I have an SVS PB-10 for a sub....
    The traps are 15 inches in diameter by 4 feet tall and I've got one roll of 15inch wide x 8inch thick x 25 feet long fiberglass insulation stuffed in fairly tightly....which didn't seem like very much insulation to me, but that's about all I could get in them.
     
  13. Vaughan Odendaal

    Vaughan Odendaal Second Unit

    Joined:
    Aug 4, 2003
    Messages:
    403
    Likes Received:
    0
    Blaine, perhaps you should measure your rooms response and find out what effect your bass traps had on overall response ?

    Just a thought. It would be interesting to find out how much your traps reduced modal ringing and if the nulls were significantly affected.

    Oh, btw, if you can, place the traps straddling the room corners. Also, if possible, leave a slight air gap (don't place the panels right against the wall). That should absorb even better.

    Let us know what happens.

    Cheers !

    --Sincerely,
     
  14. Vaughan Odendaal

    Vaughan Odendaal Second Unit

    Joined:
    Aug 4, 2003
    Messages:
    403
    Likes Received:
    0
    Thomas, I looked at that website, great info in there. However, I stumbled on this bit of information:

    "NOTE: using too many of this type of trap can lead to a room that's acoustically quite 'dead'."

    How can using too many bass traps lead to an acoustically dead room ?

    --Sincerely,
     
  15. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    Vaughan,

    What do you mean by 'straddling' the corners? They have a slight gap now between the trap and the walls, how much of a gap should there be. For the wall pannels it's hard to see in that picture, but they are about 1/2 inch or so off of the wall, not sure if it should be more than that or not.

    Blaine
     
  16. Vaughan Odendaal

    Vaughan Odendaal Second Unit

    Joined:
    Aug 4, 2003
    Messages:
    403
    Likes Received:
    0
    What I mean't is, try placing the panels across the intersecting corners at an angle so that you can leave an air gap.

    So where the the corners meet, just place the trap down at an angle covering it. Or, if possible, hang it straddling the corners higher up. BTW, how many traps do you have ?

    --Sincerely,
     
  17. Vaughan Odendaal

    Vaughan Odendaal Second Unit

    Joined:
    Aug 4, 2003
    Messages:
    403
    Likes Received:
    0
    The greater the gap, the better. So if you have 4-5" from the walls, I think that would work great ! Obviously, that might not be feasable in your situation, but if you can, try placing panels with the greatest air gap that you can manage.

    Cheers !

    --Sincerely,
     
  18. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    I have 2 traps and a limited amount of space, I can't bring my stuff out from the wall any farther than it already is. So I should put the traps out 4-5 inches from the wall then?

    PIC OF TRAPS
     
  19. Vaughan Odendaal

    Vaughan Odendaal Second Unit

    Joined:
    Aug 4, 2003
    Messages:
    403
    Likes Received:
    0
    It is just a suggestion Blaine. If it were my traps, I would try to mount them at least 2-3" from the walls. 4-5" would be ideal, in my opinion.

    The greater the air gap, the better the absorption. I would guess that modal ringing would be reduced even further. You should notice better decay times too.

    Just remember that apart from the frequency response, ringing is just as important if not more. In my room, my PB10 can sound "thick". Or boomy. But there is a significant amount of ringing in my room.

    Unfortunately, there is nothing I can do about it until funds permit.

    Heh. [​IMG]

    --Sincerely,
     
  20. Blaine_M

    Blaine_M Second Unit

    Joined:
    Mar 11, 2004
    Messages:
    400
    Likes Received:
    0
    Ok, I got them out away from the wall 4 inches (the traps that is) from both walls. Didn't get a chance to really sit down and evaluate the sound though. Sometime when I'm home sick for the day from work maybe I'll pull them out and try charting the response with and without them.......but that will be a while, the one behind the sub was not much fun getting back there : ) I'll try and get the wall pannels out a little farther as well. I won't be able to get them to much more than 2 inches however, should be able to get an extra inch over the 1 inch they are at now....
     

Share This Page