Re: My room's frequency response graph
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Joined: Mar 2003
Posts: 320
devotee
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OP
devotee
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Posts: 320 |
Hmmm, a few inches of fuzzy stuff? Would a cat work? (I am just kidding) But that idea would probably go over almost as well as asking if I can tack up some sheepskins or something. Oh well.
I'll play with a few things this weekend, and see if anything else helps. If I can direct that null to another part of the room, that might suffice.
And thanks again for your assistance.
Rich
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Re: My room's frequency response graph
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Joined: Aug 2004
Posts: 6,379 Likes: 7
axiomite
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axiomite
Joined: Aug 2004
Posts: 6,379 Likes: 7 |
Here's some interesting reading :
http://www.ethanwiner.com/acoustics.html
Owens-Corning 703 rigid fiberglass seems to be pretty absorbent at 250 Hz; might be the best option. Comes in 2'x4' panels, 1" thick...
Last edited by bridgman; 01/26/06 05:15 AM.
M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39 M5HP, M40ti, Sierra-1 LFR1100 active, ADA1500-4 and -8
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Re: My room's frequency response graph
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Joined: May 2002
Posts: 10,654
shareholder in the making
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shareholder in the making
Joined: May 2002
Posts: 10,654 |
John, there seems to be a break in the action at the moment, so I'll again raise a point about room size and power requirements. There seems to be an exaggerated concern about "filling the room" whenever it's bigger than average, and thoughts go to 500 watt amps. Room size and listener distance are certainly both factors, but sometimes the inverse square law is misapplied and a 6dB drop per doubling of distance is applied as if it was the only determinant. As has been pointed out before, the reverberent field becomes equal to the direct sound field at a relatively short distance(3-4')in typical-sized listening rooms(see the discussion and especially fig. 10.4.1 here , with the result that the drop in total sound pressure level with distance is far less than the 6dB per doubling figure. Linkwitz also has a very interesting discussion on room acoustics (especially scroll down to reverberation distance and amplifier power sections)which indicates why, as a practical matter, the more ordinary power levels that we use are fine for doing the job.
-----------------------------------
Enjoy the music, not the equipment.
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Re: My room's frequency response graph
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Joined: Mar 2003
Posts: 320
devotee
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OP
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Joined: Mar 2003
Posts: 320 |
JohnK & Bridgman--
How about the almost as large dip at 2.5Khz? Is that because it is a multiple of the 250Hz drop? But wouldn't I then expect to see drops @ 500Hz, 750Hz, and at lesser & lesser impacts as I get further away from the fundamental wave?
Doing the math at that frequency (1130ft / 2500) says the wave is ~.45 ft, or around 5.5 inches. So am I looking at multiples of the 1/2 or 1/4 of that? And since I'm right around crossover point (I think! I'm working from memory) it could be either tweeter or woofer, right? (Though the centers of both are aligned).
Any additional insights (& predictions! ) would again be appreciated.
Thanks,
Rich
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Re: My room's frequency response graph
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Joined: Mar 2003
Posts: 320
devotee
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OP
devotee
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Re: My room's frequency response graph
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Joined: Oct 2005
Posts: 853
aficionado
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aficionado
Joined: Oct 2005
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Good to see you are reading up. Here are several more for you to review with lots of info on DIY treatments .
http://www.audioholics.com/techtips/roomacoustics/roomacoustictreatments.php
http://www.audioholics.com/techtips/roomacoustics/DIYabsorbersacoustics.php
http://avsforum.com/avs-vb/showthread.php?t=255432
John
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Re: My room's frequency response graph
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Joined: Apr 2005
Posts: 2,339
connoisseur
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connoisseur
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Re: My room's frequency response graph
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Joined: Jun 2003
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axiomite
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axiomite
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Rick
"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud
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Re: My room's frequency response graph
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Joined: Jun 2003
Posts: 6,833
axiomite
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axiomite
Joined: Jun 2003
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Ya beat me to it, you type to fast
Rick
"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud
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Re: My room's frequency response graph
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Joined: Oct 2005
Posts: 853
aficionado
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aficionado
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Good linking guys. I was wondering why they don't link automatically like at other sites after cutting and pasting the links.
John
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