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In Reply to: PING Robo02... posted by Wellfed on February 16, 2007 at 22:49:40:
The Cathedral Sound Acoustic Panels are "activated" where pressure builds up in a room. Typically this would be in a three way corner: two walls and the ceiling or the floor. But in a room for instance with a peak roof this would be at this apex. The idea is that the large flat surfaces - walls, ceiling, floor - gather acoustic energy which pressurizes the points where they meet.
Follow Ups:
The only location on my upper front wall corners that appear to remotely meet your installation requirements is where my side walls intersect. I guess the ceiling itself would also allow for a snug fit to the corner. The front wall appears to be ruled out by the fact that they aren't square. Also note that the sidewall location in the "pinched" left corner would not allow for a fit within the 1/8" parameter Cathedral Sound specifies. My question now becomes, "Is any given plane as effective as the front wall location shown in your installation diagram?"
I am not 100% clear on your description of your room. If you want to send a photo or sketch you can attach to an email to ultra@ultrasystem.com or fax to 215-862-4871 and I will take a look.Two other things to note:
1. it is not all that important on which of the two walls at a corner you hang the panels (although the installation guide that comes with the Panels, or viewable online at
http://www.ultrasystem.com/usfeaturedPanelsTechInfo.html
shows the "best case" recommendations);2. you can also place the Cathedral Sound Acoustic Panels near to the floor in a corner, on the wall, or even laying flat on the floor. The corner near the ceiling is functionally preferable because the energy flows are completely unimpeded by furnishings, etc, near the ceiling, and so typically greatest there, but the next best location is in the corner near the floor.
...I do not have a square corner to work with on both of my upper front wall corners. Both side wall and ceiling corners are square.Using the diagram above
AD represents the floor corner behind my speakers
AB represents the left corner behind my speakers
DC represents the right corner behind my speakers
BC represents the front wall/ceiling boundaryIf your device requires a square corner to be effective, this would not be possible if I were limited to the upper corners on the front wall plane. It's sounds though that any of the three surfaces of a square corner are suitable locations theoretically. My preference aesthetically would be to put a pair of white units on my ceiling in each corner. In theory, is this going to be as effective as putting 1 pair on the front wall upper corners as your instructions picture?
> It's sounds though that any of the three surfaces of a square corner are suitable locations theoretically. <Just to clarify, all corners in a room are viable candidates for bass trapping. What matters most is total surface coverage, though the thickness of the panels determines how low in frequency the useful absorption extends to.
Ethan,I have your website "favorited" so am especially curious about your response: Would a pair of 11"x16"x2" panels of Owens Corning primo insulation work well as a bass trap if placed in the ceiling corners on adjacent walls?
I'd love it if you ordered some of these puppies and gave us your opinion.
I would agree with Ethan that an 11"x 16"x 2" absorptive panel is too small to have any significant impact on your low frequency response, but the Cathedral Sound Acoustic Panels, which are this size, will do the job.It is much easier to hang these on the walls than to mount them on the ceiling, and it doesn't matter that the corners are not square.
> the Cathedral Sound Acoustic Panels, which are this size, will do the job. <Do you have any lab tests or other data or graphs showing that? As far as I know the number of Sabins of absorption possible is limited by the laws of physics.
:-> )
You had asked about lab tests for the Cathedral Sound Acoustic Panels.Yes, there are before and after waterfall plots independently prepared by Rives Audio at their facility which appear on our website at:
http://www.ultrasystem.com/usfeaturedPanelsTechInfo.html
Robo (what's your name?),I'm not sure what I'm supposed to be seeing there. I can't discern any difference between the Before and After graphs other than it looks like the volume control was turned down 6 dB. Everything else - the response shape, the ringing decay times, etc is exactly the same. Usually, even minimally effective acoustic treatment has at least some affect at the higher bass frequencies. But even at the 200 Hz right side edge the two peak shapes are identical.
What am I missing?
For reference, the graph pair below shows a typical domestic size room with and without bass traps.
--Ethan
You seem confused by the scale of the change. It is much more pronounced than for instance in the waterfall plot that you posted using conventional bass traps. It is probably easiest to view the scope of the change in our plots in the decay axis, which for instance at 20-30Hz where the room was suffering the most from "overhang" is approximately halved!I have no problem with skeptics, but please don't cast aspersions on these results without any basis in fact for your comments. Once again this data was independently prepared by Richard Rives Bird at Rives Audio's own facility using one panel in each corner of a 10'x 20'x 10' room. The volume control was not "turned down" in the after results.
These results are consistent with my own experience of this product, and as you can see from other posts it is consistent with other user results.
Again, I have no problem with skeptics; I understand that from the perspective of room acoustic treatment products this is new technology. This is why these Cathedral Sound Acoustic Panels come with a 30 day money back guarantee. FYI we are still waiting for the first return, except for someone who ordered black, then changed their minds preferring off-white.
Robo,Do you have a name there?
> You seem confused by the scale of the change. <
Not confused at all, I use ETF for a living. :-> )
Again, it is obvious from looking at the slope shapes that the ringing is identical. Were you present for this testing? Do you have the original ETF data files? If so, load them both up again, and adjust the vertical dB ranges so the highest peaks are the same for each graph, and the total span from top to bottom is the same too. In this case you can leave Before as it is, but change After to display 84 dB at the top and 54 dB at the bottom. Then post screen caps here so we can see what really happens in the After graph.
I wasn't present at the lab test. I will ask the engineering folks at Nucore, Inc., the R&D company that developed the Cathedral Sound Acoustic Panels, who was present, and will post more information as I get it. Because this was an independent test it may be that only Rives personnel were present, but I don't know either way.
> I wasn't present at the lab test. <Well, this isn't really a lab test. A lab test is done in an acoustics lab! And this was obviously done in a home or office room. But I know what you mean.
> I will ask the engineering folks at Nucore, Inc., the R&D company that developed the Cathedral Sound Acoustic Panels, who was present, and will post more information as I get it. Because this was an independent test it may be that only Rives personnel were present, but I don't know either way. <
Thanks, please do post whatever you have. There's also a pending thread in the Rives section here at AA asking for the same information. Actually, even better, please ask the company reps to chime in there so we can get it from the horse's mouth, so to speak.
I think you meant "turned down 16dB"(instead of "6dB) and thanks for pointing that out, I didn't notice. But, damned if everything isn't exactly the same except that(just as you said).The only difference is the decay times from 20-56Hz. Is that simply an affect of lower volume?
Seems a little fishy without more explanation of extensive test information.
> Seems a little fishy without more explanation of extensive test information. <Even more fishy, today I find no mention of Rives on that data page. Am I hallucinating, or was there a section there just two days ago attributing this data to Rives?
Since I am seriously considering ordering 8 of these (~$700) if they are anywhere near as effective as the Waterfall plots imply, I figured it would be nice to get input from the actual testers as to the circumstances and results before spending a dime.
HowdyPerhaps you are remembering the next to last paragraph in http://www.audioasylum.com/audio/tweaks/messages/141762.html
Or perhaps this snapshot at fatwyre is the old info you are referring to http://www.fatwyre.com/email%2010_18_06.html where they say "For before and after plots prepared by Rives Audio and placement diagrams click here for technical information." with a link to the page above.
-Ted
> I think you meant "turned down 16dB"(instead of "6dB) <No, I meant 6 dB, though it's difficult to read the legends. Each vertical division is 3 dB, and the After graph is exactly the same as the Before graph except everything was slid down two divisions.
> The only difference is the decay times from 20-56Hz. Is that simply an affect of lower volume? <
No, the decay times are the same at all frequencies. If you look at the slopes you'll see they're exactly the same shape. It's just that the ringing trails have been pushed off the bottom of the graph. If the After graph were changed to display to a lower dB level, you'd then be able to see that the decays are in fact identical.
Tom,> Would a pair of 11"x16"x2" panels of Owens Corning primo insulation work well as a bass trap if placed in the ceiling corners on adjacent walls? <
It depends on how you define "work well." IMO that's too small to be effective enough. I'm sure two small panels will help, and it'd have to be better than nothing. But for most domestic size rooms I recommend at least four 2 by 4 panels, and even 16 would not be too many. It's impossible to make any room perfectly flat at bass frequencies and with no modal ringing. So all you can do is add as many bass traps as possible, and accept the results.
You've seen my living room photos with 40 traps, yes? :-> )
> I'd love it if you ordered some of these puppies and gave us your opinion. <
Ordered what puppies?
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