Acoustical Treatments Master Thread - Page 352 - AVS Forum
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post #10531 of 10541 Old 11-22-2014, 04:41 PM
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Where can I buy some inexpensive 2" batts? The Home Depot near me has Roxul but only in 3". There's seems to be only one seller online for the Roxul 2" and it's super expensive (costs a ton for shipping).
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post #10532 of 10541 Old 11-22-2014, 06:42 PM
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Quote:
Originally Posted by viperx116 View Post
Where can I buy some inexpensive 2" batts? The Home Depot near me has Roxul but only in 3". There's seems to be only one seller online for the Roxul 2" and it's super expensive (costs a ton for shipping).
I went to Lowes and had them order them for me... 2" R80. They had it delivered to me 2 days later. Now the Roxul R60 3" took a month to get as it had to be ordered out of Canada.

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post #10533 of 10541 Old 11-22-2014, 06:55 PM
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Quote:
Originally Posted by viperx116 View Post
Where can I buy some inexpensive 2" batts? The Home Depot near me has Roxul but only in 3". There's seems to be only one seller online for the Roxul 2" and it's super expensive (costs a ton for shipping).
I'm using 3" Roxul safe n sound which I can get locally. Very similar to 703 from what I read. Saves a bunch on shipping too.
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post #10534 of 10541 Old 11-22-2014, 06:57 PM
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Ill be using it for wall panels as well
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post #10535 of 10541 Old 11-22-2014, 07:28 PM
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Quote:
Originally Posted by ellisr63 View Post
I went to Lowes and had them order them for me... 2" R80. They had it delivered to me 2 days later. Now the Roxul R60 3" took a month to get as it had to be ordered out of Canada.
How much did it cost?

Edit: I'm seeing a R-8, but no R80. Is this the same?
http://www.roxul.com/products/reside...omfortboard+is

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post #10536 of 10541 Old 11-22-2014, 08:48 PM
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Non Acoustic screen treatment

Any one have a rough idea of what frequency would penetrate my Stewart Night Hawk non acoustic projector screen. I am considering some absorption in the 12 inch gap behind the screen but not sure if this makes any sense. Most high frequencies would be reflected but I'm wondering about what frequency range the screen would start to absorb?
Thanks guys.
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post #10537 of 10541 Old 11-22-2014, 09:48 PM
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I have had no luck with EQ and I'd like to correct a FR issue with room treatments.

I'd like to correct the dips in the response in the 180 Hz to 800 Hz range





How would I go about figuring out what treatments are necessary to correct that area of the FR? Or is it even possible to do that?
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post #10538 of 10541 Old 11-23-2014, 01:15 AM
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Quote:
Originally Posted by Gooddoc View Post
How would I go about figuring out what treatments are necessary to correct that area of the FR?
Relative to 10hz to 50hz, your 180 Hz to 800 Hz range should be much easier to deal with.

Start with the simple stuff:
1) See if you have any axial modes in the range. Consider putting absorption along that axis. http://www.bobgolds.com/Mode/RoomModes.htm
2) temporarily put a few 4"x2'x4' uncovered rigid fiberglass/rockwool panels vertically in all four corners, and on the floor under the screen and on the floor along the back wall of the room, Studiotips Corner Absorber style. And re-measure to see if it had an effect.
3) temporarily put 4"x2'x4' uncovered rigid fiberglass/rockwool panels at the first reflection points (side walls, front wall behind speakers, floor in front of primary listening position, and ceiling if you can). And re-measure to see if it had an effect.

(If you can't find 4", 3" is fine.)

An amateur built the Ark. Titanic was built by professionals. Of course Noah took a little advice.

Last edited by BasementBob; 11-23-2014 at 12:28 PM.
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post #10539 of 10541 Old 11-23-2014, 10:28 AM
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Quote:
Originally Posted by viperx116 View Post
How much did it cost?

Edit: I'm seeing a R-8, but no R80. Is this the same?
http://www.roxul.com/products/reside...omfortboard+is
Mine are called Rockboard 60, and Rockboard 80 on labels. I think they were around $60 per bundle. I got a deal on the R60 at $44 a bundle as it arrived damaged so we negotiated the price.

Denon 4520ci, (3) JBL 2360As/EV DHA-1s, (3) 1/4 Pie bass bins, MiniDSP 2x4s, (4) Klipsch HIPs, (2) Klipsch KP3002s, PS3, XBox 360, (3) Intel NUCs, Monoprice Redmere, Monster HTPS7000, 2 SUPER SPUD subs, Panasonic AE8000us SeymourAV 180 (195" diagonal) scope screen, Yamaha P7000s (for the subs), (2) Yamaha P2500s amps for the front (3) bass bins.
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post #10540 of 10541 Old 11-23-2014, 09:20 PM
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Quote:
Originally Posted by BasementBob View Post
Relative to 10hz to 50hz, your 180 Hz to 800 Hz range should be much easier to deal with.

Start with the simple stuff:
1) See if you have any axial modes in the range. Consider putting absorption along that axis. http://www.bobgolds.com/Mode/RoomModes.htm
2) temporarily put a few 4"x2'x4' uncovered rigid fiberglass/rockwool panels vertically in all four corners, and on the floor under the screen and on the floor along the back wall of the room, Studiotips Corner Absorber style. And re-measure to see if it had an effect.
3) temporarily put 4"x2'x4' uncovered rigid fiberglass/rockwool panels at the first reflection points (side walls, front wall behind speakers, floor in front of primary listening position, and ceiling if you can). And re-measure to see if it had an effect.

(If you can't find 4", 3" is fine.)
Thanks for the input. The calculator only went up to 180 Hz. but gave some great room information. Particularly that the Schroeder frequency is only about 100 Hz. It does give me a good idea where to start with treatments for the 50-70 Hz area


I have GIK 3.5" treatments at the 2nd reflection points and floor to ceiling GIK bass traps in all four corners. 1st reflection points are a challenge and I haven't bothered with them yet. There is some thought out there that suggests I might not even want to bother with them.


Still pretty much have no idea how to fix that 180 - 800 Hz area, any other suggestions with the additional information?

Thanks a whole lot!
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post #10541 of 10541 Old 11-23-2014, 11:11 PM
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Gooddoc:

Some more ideas for you to consider.

Apologies about the room mode calculator not working above 200hz. Actually that's probably a practical limit for modes anyway -- so I shouldn't have mentioned 'a room modes calculator' for 200-800hz it at all.. If you want to see the numbers higher anyway, you can go back to http://www.bobgolds.com/Mode/RoomModes.htm , push the SHOW OPTIONS button, and enter a hz value after "show frequencies less than".


Quote:
Originally Posted by Gooddoc View Post
I have GIK 3.5" treatments at the 2nd reflection points and floor to ceiling GIK bass traps in all four corners. 1st reflection points are a challenge and I haven't bothered with them yet.

Cool that you already have absorbers.
Temporarily move all the 2nd reflection point absorbers to the 1st reflection point (in front of that door for example) and the floor wall locations (4 sides) and see what happens. If you don't have enough or they are rather permanently mounted, make a trip to home depot for some rigid rockwool panels. You will take these out of the bags.


If you have a front/back axial mode and you haven't seen your spouse raise an eyebrow lately, get 14 bags of fluffy fiberglass pink insulation, do not take them out of the bags, then stack them 7 wide and 8' tall across the back wall, and then give the room a listen.


Quote:
Originally Posted by Gooddoc View Post
There is some thought out there that suggests I might not even want to bother with them.
Yes, there is a school of thought that says that there's a richness of sound field gain from first reflection point (indeed bipolar speakers go out of their way at this), and another school of thought that says that first reflections should be dropped by 12 to 20dB at all frequencies. Too little reflected energy and the room is cold and dead, too much and the room echoes, has strong directional impressions, false stereo imaging, poor sound clarity, and a narrow soundstage.


Be curious. Experiment with the Simple. See if you like the sound, both by ear and by measurement. Language clarity (anything in a language you barely speak, my mother being fluent in english her entire life would suggest anything from the United Kingdom would foot the bill), imaging (Star Wars Pod Race, Mission To Mars rotation scene, etc). Presumably there's something you have been listening to that you are confident isn't sounding right -- use that too.


Alternatively, you could try diagnosis, followed by treatment. [This will go faster if you get the feedback of someone who can do this for you (or hire someone competent, probably with a degree in Acoustics, but at least does it routinely possibly with an AVS customer appreciation).]
- verify background noise
- initial speaker placement (L/R 3 feet from walls, etc)
- check speaker and cable integrity, check speaker time delay, and sound level balance
- test each speaker individually for reflections, and ensure the high frequency reflections are 12dB quieter than direct sound. Measure the ITDG (all peaks within 25-30mSec should be 12dB below the direct sound level)
- deal with room modes via subwoofer positioning and a RTA.
- set the subwoofer crossover frequency for a room reason rather than a speaker reason.
- verify a lack of vibration via a slow sweep 11hz to 400hz.


(Do you have a multi-channel digital equalizer? I don't have one, but I hear they're the cat's meow. Just a thought.)
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Last edited by BasementBob; 11-23-2014 at 11:18 PM.
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