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post #6091 of 9543
Quote:
Originally Posted by AustinJerry View Post
 
Quote:
Originally Posted by kbarnes701 View Post
 

 

J - how accurate are these Skopus-style traps wrt to the frequency they target? If you look at my current waterfall, the problem I have seems to span 45-55Hz-ish. Would the 50Hz trap you mention above be the right one to target that issue? I would love to improve that region and adding the latest round of additional gubbins didn't do it for me. Sanjay tells me this is a length mode (with suggestions I test for it, which I will) - if he is correct then I could use the targeted traps in the window space as described before couldn't I - even though there will be closed drapes in front of them?  I am thinking that if they are hidden in this way I might be able to DIY them using your design.

 

 

 

Keith, re the Scopus traps, I posted a small graph that showed the target frequencies and Q for each trap.  GIK will build custom traps for whatever frequency you want to target, at no additional charge.  Each order is a custom build anyway, and changing the target frequency is a simple as varying the dimensions of the components, IIUC.

 

Thanks Jerry. I missed that post you refer to. My AVS email notifications have gone patchy again...

 

Do you know how 'tight' the target frequency is?  My issue seems to be 45-55hz - would a Skopus trap targeting 50Hz do the job?  I may go this route - but I will wait until I have the benefit of your pioneering experience I think - this is a totally new area for me. I might even build them as they will be hidden (if J says they will work in the one and only place I can locate them).

Gear mentioned in this thread:

post #6092 of 9543
Quote:
Originally Posted by jkasanic View Post
 

Thanks for the detail on your trap design.  I wish I had the expertise, time and patience to do a guide as Jerry requested.  I'm guessing if you could take a few pics of your upcoming trap build then throwing them in a guide wouldn't be so painful?  Perhaps we could just add this info to the guide Keith mentioned he would throw together for his latest treatments?!  Not sure what your PM inbox contents are but if it's anything like the one I sent you then perhaps spending a little time on this would relieve that burden somewhat?  Just a thought...selfish as it may be! :cool:

 

I don't want to volunteer for a treatments guide as I am not all that savvy on the subject, but I am thinking of making the Donut Guide an editable Wiki-style document, hosted in my DropBox folder. If people want to download it and add stuff to it, they are more than happy to do so and then send the modded doc back to me and I will repost it. It's a bit clumsy but the best I can think of. And first I will need to do the Donut Guide - RSN, promise.

post #6093 of 9543
Quote:
Originally Posted by kbarnes701 View Post

Thanks Jerry. I missed that post you refer to. My AVS email notifications have gone patchy again...

Do you know how 'tight' the target frequency is?  My issue seems to be 45-55hz - would a Skopus trap targeting 50Hz do the job?  I may go this route - but I will wait until I have the benefit of your pioneering experience I think - this is a totally new area for me. I might even build them as they will be hidden (if J says they will work in the one and only place I can locate them).

Here is the post. As far as whether the 50Hz trap will do the job, your guess is as good as mine.

http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/5840_20#post_23888097
post #6094 of 9543
Quote:
Originally Posted by sdrucker View Post
 
 
FWIW, you're never done unless you stop reading, or turn off your computer haha....I can't tell you how many times Keith has said something like "I've made my room as good as it can be". I think the first time was when he spent two weeks diagnosing a phase issue with his subs and the Pro kit. And that was BEFORE his Seaton woofage and treatments, as well as REW. And even Jerry was on temporary measurement break at one point recently IIRC.
 

 

Haha. Ain't that the truth! I sorted that phase issue, then I got the Submersives and started all over again. Then I said "I'm done now". Then I added treatments. Then I said "I'm done now". Then I relocated the speakers and subs. Then I said "I'm done now". Then I added more treatments. Then I said "I'm done now". Then I bought a PJ. Then I said "I'm done now". Then I bought an expensive screen. Then I said "I'm done now". Now I am waiting for a new PJ to be delivered. And I painted the room black and gray. Then I said "I'm done now".  And fitted new carpets and curtains. Then I said "I'm done now". Then I made some bass traps and added a load of additional absorption to the existing traps. Then I said "I'm done now". Somewhere along the way I repositioned the seating a little closer to the screen. Then I said "I'm done now". And moved the Height speakers. Then I said "I'm done now". And raised the height of the surround speakers. Then I said "I'm done now". Now I have a little issue at 45-55Hz which may require a venture into tuned membrane traps. But then I think I will be done LOL.

post #6095 of 9543
Quote:
Originally Posted by AustinJerry View Post
 
Quote:
Originally Posted by kbarnes701 View Post

Thanks Jerry. I missed that post you refer to. My AVS email notifications have gone patchy again...

Do you know how 'tight' the target frequency is?  My issue seems to be 45-55hz - would a Skopus trap targeting 50Hz do the job?  I may go this route - but I will wait until I have the benefit of your pioneering experience I think - this is a totally new area for me. I might even build them as they will be hidden (if J says they will work in the one and only place I can locate them).

Here is the post. As far as whether the 50Hz trap will do the job, your guess is as good as mine.

http://www.avsforum.com/t/1449924/simplified-rew-setup-and-use-usb-mic-hdmi-connection-including-measurement-techniques-and-how-to-interpret-graphs/5840_20#post_23888097

 

Thanks Jerry.  I am guessing that if the the T-40's tuned to 40Hz have an  range of 30-55Hz, something tuned to about 50Hz would suit me. I think, once we have the results in from your experiments, I will email my waterfall to Bryan Pape and see what he recommends.

post #6096 of 9543
Sounds good. I should have results this time next week. I just received the notification that my traps have shipped. I am going to spend the rest of the day setting up my new iPad Air. biggrin.gif
post #6097 of 9543
BTW, to everyone. I recently created a thread with a description of my system, measurements, etc. Keith made a comment that it is useful to have all this stuff in one place. He and I have discussed on several occasions how difficult it is providing assistance to thread participants when we can't remember critical information about the participant's listening room, equipment, etc.

Personally, I think we should encourage everyone to create a "My Set-Up" thread so that we can refresh our memories WRT pertinent information as we are working through issues. Whaddya think?
post #6098 of 9543
Quote:
Originally Posted by artur9 View Post

I'm going through the Acoustical Treatments Master Thread trying to find an answer to a question. Hard to believe that thread has been going for 10 years. Then again, gabfest! smile.gif

So far, I found that making a tube trap that is also a fake column would work and help with the WAF. But what I want to know is whether putting a triangular (or square) bass trap into the drop ceiling along the corners works. Anyone know? I'm planning to put more sound insulation up there anyway so hoping to address both issues at once.
Are you talking about bass traps hidden above a drop ceiling or soffits? Soffit traps work. There's no question about it. If the drop ceiling uses the typical sort of tiles, then those are more or less transparent to bass frequencies too, so they will work as well. Yes, you can fill all the wall-ceiling intersections with square (or triangular) soffit bass traps.


Max
post #6099 of 9543
Quote:
Originally Posted by AustinJerry View Post

BTW, to everyone. I recently created a thread with a description of my system, measurements, etc. Keith made a comment that it is useful to have all this stuff in one place. He and I have discussed on several occasions how difficult it is providing assistance to thread participants when we can't remember critical information about the participant's listening room, equipment, etc.

Personally, I think we should encourage everyone to create a "My Set-Up" thread so that we can refresh our memories WRT pertinent information as we are working through issues. Whaddya think?

 

I think it's an excellent idea, Jerry. I seem to have no more to do right now in the HT, or nothing that is pressing anyway, so next week I will do the Donut Guide to how I made my DIY bass trap, complete with blurry phone photos <g> and see if I can co-ordinate the required info to emulate your 'my setup' thread. I say 'next week' as I like to spend less time on this stuff over the weekend so that I can devote more of my time to Mrs K.

post #6100 of 9543
Quote:
Originally Posted by kbarnes701 View Post

Quote:
Originally Posted by AustinJerry View Post

 
Quote:
Originally Posted by kbarnes701 View Post

 

J - how accurate are these Skopus-style traps wrt to the frequency they target? If you look at my current waterfall, the problem I have seems to span 45-55Hz-ish. Would the 50Hz trap you mention above be the right one to target that issue? I would love to improve that region and adding the latest round of additional gubbins didn't do it for me. Sanjay tells me this is a length mode (with suggestions I test for it, which I will) - if he is correct then I could use the targeted traps in the window space as described before couldn't I - even though there will be closed drapes in front of them?  I am thinking that if they are hidden in this way I might be able to DIY them using your design.




Keith, re the Scopus traps, I posted a small graph that showed the target frequencies and Q for each trap.  GIK will build custom traps for whatever frequency you want to target, at no additional charge.  Each order is a custom build anyway, and changing the target frequency is a simple as varying the dimensions of the components, IIUC.

Thanks Jerry. I missed that post you refer to. My AVS email notifications have gone patchy again...

Do you know how 'tight' the target frequency is?  My issue seems to be 45-55hz - would a Skopus trap targeting 50Hz do the job?  I may go this route - but I will wait until I have the benefit of your pioneering experience I think - this is a totally new area for me. I might even build them as they will be hidden (if J says they will work in the one and only place I can locate them).

Keith, the GIK page for Scopus traps has their coefficient vs frequency graph of the 3 standard tune traps at 40Hz, 70Hz and 100Hz.

http://gikacoustics.com/product/gik-acoustics-scopus-tuned-bass-trap-t100/#!lightbox/3/

As you can see, the Scopus traps are effective out to 10Hz on either side of the tune (and have an effect out to almost 20Hz). If you have them build you 50Hz tuned traps they should definitely help the 45-55Hz problem region if placed in optimal spots.


Have you measured your possible placement positions to see if they lie in a peak region at the problem frequencies? You wouldn't even really need to setup all the equipment. Just setup a tone generator at that frequency range and then use the SPL meter and move slowly along the walls (small room so it won't take long) to see where the SPLs peak for those particular frequencies. Unless the only placement position is in a null (where SPLs at those frequencies are lowest), they will have some effect. The greatest attenuation though, will result from placing them where the SPL meter reads highest for the tuned frequency of the membrane trap.


Max

P.S. if it's possible to do so and there's enough room, you can actually place membrane traps behind higher frequency panels.
Edited by djbluemax1 - 11/1/13 at 2:36pm
post #6101 of 9543
Quote:
Originally Posted by kbarnes701 View Post

Haha. Ain't that the truth! I sorted that phase issue, then I got the Submersives and started all over again. Then I said "I'm done now". Then I added treatments. Then I said "I'm done now". Then I relocated the speakers and subs. Then I said "I'm done now". Then I added more treatments. Then I said "I'm done now". Then I bought a PJ. Then I said "I'm done now". Then I bought an expensive screen. Then I said "I'm done now". Now I am waiting for a new PJ to be delivered. And I painted the room black and gray. Then I said "I'm done now".  And fitted new carpets and curtains. Then I said "I'm done now". Then I made some bass traps and added a load of additional absorption to the existing traps. Then I said "I'm done now". Somewhere along the way I repositioned the seating a little closer to the screen. Then I said "I'm done now". And moved the Height speakers. Then I said "I'm done now". And raised the height of the surround speakers. Then I said "I'm done now". Now I have a little issue at 45-55Hz which may require a venture into tuned membrane traps. But then I think I will be done LOL.

Hi, my name is Keith and I struggle with... smile.gif

Quote:
Originally Posted by AustinJerry View Post

Sounds good. I should have results this time next week. I just received the notification that my traps have shipped. I am going to spend the rest of the day setting up my new iPad Air. biggrin.gif

Very nice Jerry! I have the iPad 4 so no upgrade for me. I got my Mac mini in March that I am loving. Quad core i7 processor, 16gb ram, 1TB hard drive.
Quote:
Originally Posted by AustinJerry View Post

BTW, to everyone. I recently created a thread with a description of my system, measurements, etc. Keith made a comment that it is useful to have all this stuff in one place. He and I have discussed on several occasions how difficult it is providing assistance to thread participants when we can't remember critical information about the participant's listening room, equipment, etc.

Personally, I think we should encourage everyone to create a "My Set-Up" thread so that we can refresh our memories WRT pertinent information as we are working through issues. Whaddya think?

I think that is a great idea. I'm in. Where do we create these threads? I have that link to my HT gear but I like the thread where I can constantly modify my information
post #6102 of 9543
Quote:
Originally Posted by AustinJerry View Post

BTW, to everyone. I recently created a thread with a description of my system, measurements, etc. Keith made a comment that it is useful to have all this stuff in one place. He and I have discussed on several occasions how difficult it is providing assistance to thread participants when we can't remember critical information about the participant's listening room, equipment, etc.

Personally, I think we should encourage everyone to create a "My Set-Up" thread so that we can refresh our memories WRT pertinent information as we are working through issues. Whaddya think?

I have made this comment also. I have one already at GS that I started back in March or else I would join you. Its quite handy sometimes to look back at early work and measurements and you also attract comments and suggestions that pertain directly to your own project.

Quite a boon id say.
post #6103 of 9543
Also I am all in and creating the DIY treatment section. I am certainly not the most qualified but I feel I can gather the necessary information to provide for anybody that's in need. I can do this with collaborating with you guys and J. Also I have found very good information over on gearslutz. I can also provide information on how to use the porus calculator thing that J link that allows us to compare insulation and thicknesses and their effectiveness at what HZ. I can also provide a very detailed pictures of my entire build process as well as collect others from other members here.

My question is do I create a thread for this and then simply we create a link? I could probably get it together and all the necessary information over the next 3 to 4 weeks.

Plus I am sure J and other qualified people would chime in on the thread as well

It could become kind of like a sister thread to this one and we could in general keep the information in each respective thread jumping back-and-forth. That way in the DIY treatment thread we won't feel off-topic by posting anything or any pictures or descriptions of builds
post #6104 of 9543
Quote:
Originally Posted by jim19611961 View Post

I have made this comment also. I have one already at GS that I started back in March or else I would join you. Its quite handy sometimes to look back at early work and measurements and you also attract comments and suggestions that pertain directly to your own project.

Quite a boon id say.

We love those boon's Jim smile.gif
post #6105 of 9543
Quote:
Originally Posted by jlpowell84 View Post

Hi, my name is Keith and I struggle with... smile.gif
Very nice Jerry! I have the iPad 4 so no upgrade for me. I got my Mac mini in March that I am loving. Quad core i7 processor, 16gb ram, 1TB hard drive.
I think that is a great idea. I'm in. Where do we create these threads? I have that link to my HT gear but I like the thread where I can constantly modify my information

Works for me. Let me see what I can compile myself next week...

By the way, I was searching bass traps and stumbled into this product. Anybody ever hear of the "Spatial Computer Black Hole Anti-Wave generator"? It looks like a weird mod/replacement for a subwoofer....possibly (maybe probably) advanced quackery, but considering that an odd product like the Darblet produces out of the envelope results for some users, it's not completely bizzare:

http://www.spatialcomputer.com/page9/page10/page10.html

Edit: ...and apparently it no longer exists if you click on the "Order" link. Which tells you something LOL...
Edited by sdrucker - 11/1/13 at 3:21pm
post #6106 of 9543
Quote:
Originally Posted by djbluemax1 View Post
 
Quote:
Originally Posted by kbarnes701 View Post
 
Quote:
Originally Posted by AustinJerry View Post

 
Quote:
Originally Posted by kbarnes701 View Post

 

J - how accurate are these Skopus-style traps wrt to the frequency they target? If you look at my current waterfall, the problem I have seems to span 45-55Hz-ish. Would the 50Hz trap you mention above be the right one to target that issue? I would love to improve that region and adding the latest round of additional gubbins didn't do it for me. Sanjay tells me this is a length mode (with suggestions I test for it, which I will) - if he is correct then I could use the targeted traps in the window space as described before couldn't I - even though there will be closed drapes in front of them?  I am thinking that if they are hidden in this way I might be able to DIY them using your design.



Keith, re the Scopus traps, I posted a small graph that showed the target frequencies and Q for each trap.  GIK will build custom traps for whatever frequency you want to target, at no additional charge.  Each order is a custom build anyway, and changing the target frequency is a simple as varying the dimensions of the components, IIUC.

Thanks Jerry. I missed that post you refer to. My AVS email notifications have gone patchy again...

Do you know how 'tight' the target frequency is?  My issue seems to be 45-55hz - would a Skopus trap targeting 50Hz do the job?  I may go this route - but I will wait until I have the benefit of your pioneering experience I think - this is a totally new area for me. I might even build them as they will be hidden (if J says they will work in the one and only place I can locate them).

Keith, the GIK page for Scopus traps has their coefficient vs frequency graph of the 3 standard tune traps at 40Hz, 70Hz and 100Hz.

http://gikacoustics.com/product/gik-acoustics-scopus-tuned-bass-trap-t100/#!lightbox/3/

As you can see, the Scopus traps are effective out to 10Hz on either side of the tune (and have an effect out to almost 20Hz). If you have them build you 50Hz tuned traps they should definitely help the 45-55Hz problem region if placed in optimal spots.


Have you measured your possible placement positions to see if they lie in a peak region at the problem frequencies? You wouldn't even really need to setup all the equipment. Just setup a tone generator at that frequency range and then use the SPL meter and move slowly along the walls (small room so it won't take long) to see where the SPLs peak for those particular frequencies. Unless the only placement position is in a null (where SPLs at those frequencies are lowest), they will have some effect. The greatest attenuation though, will result from placing them where the SPL meter reads highest for the tuned frequency of the membrane trap.


Max

P.S. if it's possible to do so and there's enough room, you can actually place membrane traps behind higher frequency panels.

 

Great stuff - thanks Max. Yes I intend to use REW to measure for effective placement. Once more into the rabbit hole....

post #6107 of 9543
Quote:
Originally Posted by AustinJerry View Post







ULF=50 looks better, which is coincidently how I have my subs set.

Maybe it's just me, but I find the spectrogram considerably easier to interpret than the waterfall, as it tells us about the overall picture WRT the speed of decay without the need for multiple charts at different ms time windows. At least if that's the primary purpose of assessment for these two chart types.

Time to play with my ULS trims over the weekend....and hash out what I want the ULS to do vs. the Audyssey Pro Curve Editor, and see how either/both help me out on the bass decay, if at all, if I get a satisfactory target curve. BTW I'm going to do some SPL measurement against my walls (well, the width one and the very limited short wall I have as a "length" wall on the right side of our room; the left side is mostly open space onto the hallway and dining room) to see where I might go with a tuned membrane trap based on your experience. Lots of pieces to leverage...and exactly why changing the room, even inadvertedly, opens up Pandora's box of "how do I do it better"...
Edited by sdrucker - 11/1/13 at 4:12pm
post #6108 of 9543
Quote:
Originally Posted by jlpowell84 View Post


I think that is a great idea. I'm in. Where do we create these threads? I have that link to my HT gear but I like the thread where I can constantly modify my information

Here is where I set mine up. It really doesn't matter where you capture the information, even on a different forum, as long as you have a link in your sig.

AVS › AVS Forum › Home Entertainment & Theater Builder › General Home Theater & Media/Game Rooms ›
post #6109 of 9543
Jim1961, if I remember right you linked a site that that specked the flow resistivity of all types of insulation. Would you be so kind as to do so again? smile.gif
post #6110 of 9543
Quote:
Originally Posted by jlpowell84 View Post

Jim1961, if I remember right you linked a site that that specked the flow resistivity of all types of insulation. Would you be so kind as to do so again? smile.gif

http://www.bobgolds.com/AbsorptionCoefficients.htm
post #6111 of 9543
Thanks Jim I really needed it. Bookmarked now!
post #6112 of 9543
Perhaps you could help me Jim. I had my insulation delivered today and I think it may be the wrong stuff. I talked with the sales guy so an exchange is available. I ordered Roxul AFB and what the label says is Roxul RHT 80. So with that link Jim how can I find the flow resistivity number to put into the porous absorber calculator? I see numbers but not like 5000 for pink fluffy or 27000 for AFB.

Also can you give any insight if what I have is AFB (perhaps a diff name?) or is RHT 80 something else?


post #6113 of 9543
Quote:
Originally Posted by jim19611961 View Post

Quote:
Originally Posted by jlpowell84 View Post

Jim1961, if I remember right you linked a site that that specked the flow resistivity of all types of insulation. Would you be so kind as to do so again? smile.gif
http://www.bobgolds.com/AbsorptionCoefficients.htm
Jason had earlier linked to an old GearSlutz thread where gas flow resistivity values were listed (and argued about) for many popular acoustic materials, but is there a way to reliably convert those absorption coefficients and/or density figures from the Bob Golds chart to gas flow resistivity numbers?.
post #6114 of 9543
Quote:
Originally Posted by jlpowell84 View Post

Perhaps you could help me Jim. I had my insulation delivered today and I think it may be the wrong stuff. I talked with the sales guy so an exchange is available. I ordered Roxul AFB and what the label says is Roxul RHT 80. So with that link Jim how can I find the flow resistivity number to put into the porous absorber calculator? I see numbers but not like 5000 for pink fluffy or 27000 for AFB.

Also can you give any insight if what I have is AFB (perhaps a diff name?) or is RHT 80 something else?



Matching it up with a material that has a similar density and thickness will get you close. RHT 80 (94 kg/m3) looks like over twice the density of AFB (40 kg/m3). Not close. Personally, I would make them exchange it. I find the less dense materials do a better job when thick enough.
Edited by jim19611961 - 11/1/13 at 7:42pm
post #6115 of 9543
Quote:
Originally Posted by jim19611961 View Post

Matching it up with a material that has a similar density and thickness will get you close. RHT 80 (94 kg/m3) looks like over twice the density of AFB (40 kg/m3). Not close. Personally, I would make them exchange it. I find the less dense materials do a better job when thick enough.

Ok, do we know the gas flow resistivity number like Sanjay mentioned above? Twice as dense mean it will go from the AFB number of 27000 to 54000?

It is pretty heavy stuff
post #6116 of 9543
Quote:
Originally Posted by jlpowell84 View Post

Ok, do we know the gas flow resistivity number like Sanjay mentioned above? Twice as dense mean it will go from the AFB number of 27000 to 54000?

It is pretty heavy stuff

The RHT 80 models about like Owens Corning 705 (27000). AFB models like OC 703 (16000). Look at the density of your materials, they compare with the 703 and 705. The modeling wont be exact, but ballpark.

I have seen OC703 resistivity quoted as 27000, 21000 and 16000. So expect some controversy. There are whole threads arguing which it is. But NASA modeled the stuff and 16K was their figure. I trust NASA to get it right smile.gif
post #6117 of 9543
Quote:
Originally Posted by sdurani View Post

Jason had earlier linked to an old GearSlutz thread where gas flow resistivity values were listed (and argued about) for many popular acoustic materials, but is there a way to reliably convert those absorption coefficients and/or density figures from the Bob Golds chart to gas flow resistivity numbers?.

I have read the thread you refer to at GS. I think 5K for R19 (pink fluffy), 16k for 703, and 27K for 705 are pretty good numbers for the Owens Corning products. Cant say about the others.
post #6118 of 9543
Also just to be clear this is the site I bought from. I have $200 paid so I can exchange for what I need. I won't need as much Roxul AFB since my front LR vertical (about 15x15) and LR floor to wall coming back about 8 ft will be a 10x10 soffit. I will put some up on the front wall too. Maybe I can do the wall to ceiling junctions too! Heck soffits all around! Case is I will need a bunch of pink fluffy which they sale as well although their dimensions look different from the lowes and Home Depot dimensions. In fact I don't know if I will need any Roxul AFB now because the porous calculator shows pink fluffy is better from 400hz on up at 4 inches thick. Although the calculator is telling me if I want some 45hz and down absorption then I need some thick AFB

http://insulationsaver.com/
post #6119 of 9543
OK, here's my initial results from the first day of pushing 4 subs around my living room. smile.gif

4880 cubic feet, quad XS15s, Audyssey on, Dyn EQ on, subs + FL/R.

This is unsmoothed FR:


FR with 1/6th octave smoothing:


Waterfall (my noise floor is around 52db):


Spectrogram:


And here is the FR from my wife's recliner in blue, mine in green...initially, I thought it looked better than my response, but after closer inspection I think mine more resembles a proper house curve smile.gif :



What do you guys think? Lookin' good or should I still consider the Mini DSP? Room treatments?
post #6120 of 9543
Quote:
Originally Posted by jim19611961 View Post

The RHT 80 models about like Owens Corning 705 (27000). AFB models like OC 703 (16000). Look at the density of your materials, they compare with the 703 and 705. The modeling wont be exact, but ballpark.

I have seen OC703 resistivity quoted as 27000, 21000 and 16000. So expect some controversy. There are whole threads arguing which it is. But NASA modeled the stuff and 16K was their figure. I trust NASA to get it right smile.gif

Yea I found that nasa document in my research. Jevansoh was saying AFB was 27000 last night so I had assumed that was right. If the RHT 80 is in fact 27000 and AFB 16000 then I should keep a little.

Actually I have an idea. Let's see what you think. Let's say I am going to build two big vertical soffit traps in my front LR corners (note that the right corner will have a good 3.5 ft gap due to a dang in wall air conditioner). Those 15x15 out of entirely pink fluffy. Here is the absorption calc on 15". I put 15" of the 27000 value as well just so we can see why we would want pink fluffy!


I am thinking I could get away with about 9 inch soffits all around elsewhere. Floor to wall coming back from front LR corners, tv wall from front LR corners about 5ft in both sides until I hit the tv stand. And front tv wall to ceiling junction, and both LR side wall to ceiling junction.

Here is 9 inches...
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