Newbie help anyone?
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Allbaldo
- Posts: 7
- Joined: Wed Oct 20, 2004 10:42 pm
- Location: Tulsa, Oklahoma. USA
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Newbie help anyone?
My room is 14.5 wide, 18.5 long, and 12 tall, and made of sheetrock. It's way too live and bouncy, so being broke, I made some 2x4 covered absorbers out of rockwool sheets with stiff backing, and cloth over them. I staggered them around the upper half of the room where I could hear the most crap floating around. This seems to have had the disturbing effect of making the room dead-er, but uncovering a very specific standing wave. Does this sound possible? Any suggestions...for a broke acoustics novice?
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knightfly
- Senior Member
- Posts: 6976
- Joined: Sun Mar 16, 2003 11:11 am
- Location: West Coast, USA
Yes, it's possible; but I'm not seeing any modal problems with those dimensions, so it may be positioning of speakers or you, a wall/floor/ceiling resonance, or??!?
Can you give more details, such as the frequency of the problem, what speakers, exact positioning in all three axes within the room, whether the problem is audible no matter where in the room you are, what OTHER medium to large-sized items there may be in the room...
Generally, one of the first treatments we advise for a room (if possible) is to place absorbers similar to yours across all four vertical corners of a room - but WITHOUT backing. Just 4" rockwool slabs, preferably 3' wide, diagonally floor to ceiling in the corners. More of these (still NOT backed) 4-6" away from the wall BEHIND the speakers, large enough so you can see a foot or more of the absorber sticking out past either speaker on both sides and above - next, same thing on side walls where placing a mirror would show you (from listening position) either speaker (these are called first reflection points) - same thing for ceiling -
Placing a hard backing on absorbent isn't advised in most cases; by leaving that out and spacing the absorbent approximately its own thickness away from the wall, you get absorption to about 1 full octave lower than just placing the material directly on the wall. (If you're dealing with a lady in residence, you may need to get creative in how you make this look
)
Finally, across the back wall - if the room is still too live by this time, more of the 4" unbacked panels, further off the wall if there's room. If it's getting too dead in there, (can be dependent on wall/ceiling/floor construction) then replace the rear absorbers with a few tall bookshelves, with randomly placed (not neat, even faced out books) objects on the shelves (nothing that rattles)
If there is STILL too much "boom", the diagonal treatment can be extended to the wall/ceiling corners for more modal absorption. Corners are where all modes terminate, so this is a good place to "catch" them...
Small patches won't do much of anything in almost all cases, and you may find that up to 25% of your total surface is treated before you are happy - depends on all the above factors plus your own idea of what is "too dead"... Steve
Can you give more details, such as the frequency of the problem, what speakers, exact positioning in all three axes within the room, whether the problem is audible no matter where in the room you are, what OTHER medium to large-sized items there may be in the room...
Generally, one of the first treatments we advise for a room (if possible) is to place absorbers similar to yours across all four vertical corners of a room - but WITHOUT backing. Just 4" rockwool slabs, preferably 3' wide, diagonally floor to ceiling in the corners. More of these (still NOT backed) 4-6" away from the wall BEHIND the speakers, large enough so you can see a foot or more of the absorber sticking out past either speaker on both sides and above - next, same thing on side walls where placing a mirror would show you (from listening position) either speaker (these are called first reflection points) - same thing for ceiling -
Placing a hard backing on absorbent isn't advised in most cases; by leaving that out and spacing the absorbent approximately its own thickness away from the wall, you get absorption to about 1 full octave lower than just placing the material directly on the wall. (If you're dealing with a lady in residence, you may need to get creative in how you make this look
)Finally, across the back wall - if the room is still too live by this time, more of the 4" unbacked panels, further off the wall if there's room. If it's getting too dead in there, (can be dependent on wall/ceiling/floor construction) then replace the rear absorbers with a few tall bookshelves, with randomly placed (not neat, even faced out books) objects on the shelves (nothing that rattles)
If there is STILL too much "boom", the diagonal treatment can be extended to the wall/ceiling corners for more modal absorption. Corners are where all modes terminate, so this is a good place to "catch" them...
Small patches won't do much of anything in almost all cases, and you may find that up to 25% of your total surface is treated before you are happy - depends on all the above factors plus your own idea of what is "too dead"... Steve
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...