hangers

T

Tonio

New member
Ok folks lets talk bass hangers. How much is a minimum space needed to say kill 120 hz? Is 6" depth too small to do any good? 1'?
Where's Rick ?
 
If you're trying to do this with absorption, good luck; the 1/4 wavelength of 120 hZ is just over 28 inches; meaning, if you want absorption optimised at that freq. you'll need it to be 28-30 inches away from a solid boundary, and if your 120 hz problem happens in more than one axis the trap would need to be located in a common corner in order to do much.

Do you have an actual problem at that freq, or is this a theoretical question aimed at improving general knowledge of acoustics?

It might help if you were to describe your space, maybe even post a simple drawing or pic, or both; if you give dimensions, I can run a FULL modal analysis to see if you actually have a problem; sometimes there are enough tangential and oblique modes in between axials to smooth out what may have looked like a problem to a simple axial mode calculator... Steve
 
knightfly said:
If you're trying to do this with absorption, good luck; the 1/4 wavelength of 120 hZ is just over 28 inches; meaning, if you want absorption optimised at that freq. you'll need it to be 28-30 inches away from a solid boundary, and if your 120 hz problem happens in more than one axis the trap would need to be located in a common corner in order to do much.

Do you have an actual problem at that freq, or is this a theoretical question aimed at improving general knowledge of acoustics?

Steve
Click to expand...
Steve,
Been doing some reworking .....
Actually I do have a problem @ 100-140 or so, not to mention others. But I also am trying to improve general knowledge of of acoustics. I was afraid that bass hangers would not work in my case:
17X11.3X9. The ceiling also has Ultra touch R13 in the rafters covered with
fabric, and a 2X4 cloud above mix position, a 4X4 cloud in the rear. Also a 4X4 absorber on rear wall.
Let me know it it would be easier to actually register over at Jons' forum. Appreciate your help.

T


 
I'd need details on speaker and mic location (and type) before those would mean much - only thing I see that might cause such a response is height; if your woofers are between 4 and 5 feet off the floor, you might be getting a second harmonic peak based on your 9 foot room height. Using all three types of modes though, the room doesn't seem that bad. I'm thinking it's more positioning than modes.

If you want to see just the room's response, try putting ONE speaker in the bottom front left corner of the room and an OMNI mic at the top rear right corner.

HTH... Steve
 
woofers are @ 33" from floor. 53" triangle(centered to room width)or 41.5" from side walls , 27" from front wall-mix position approx.75" from front wall. I think I'm good for the 38% rule ect.
I used a TR40 omni @ mix position, though there wasn't much change either in the center of the room or in the rear. Maybe some expected peak towards the rear.
Funny thing is that I had the 2 front wall corner BB absorbers( 703-1")covered with peg board and burlap. due to some opinions, I took off the peg board and added 2"more 703 the low end got worse.:eek:
BTW its a dual use room, so I'm trying not to get it too dead. I'll give your suggestion a try.
Thank you for taking your time to help me out.

:D

T
 
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