Room Acoustics Forum by Rives Audio Welcome! Need support, you got it. Or share you ideas and experiences.

---

[ Follow Ups ] [ Post Followup ] Thread: [ Display  All  Email ] [ Room Acoustics Forum by Rives Audio ]

---

[ Alert Moderator ]

---

Re: Ethan and MahlerFreak

Posted by Ethan Winer (M) on March 9, 2007 at 14:53:31

In Reply to: Ethan and MahlerFreak posted by David Aiken on March 8, 2007 at 19:15:06:

David,

> Ethan's ... argument fails if they work by some other method because it relies on comparing apples with oranges if the method is different. <

No, because:

> MahlerFreak claims ... these panels can't do better than a perfect absorber <

Which is irrefutable.

> Such an argument, however, doesn't prove that they don't do what the waterfall plots claim they do. <

David, those waterfall plots are totally bogus. I'm sorry if you don't understand that, but I've explained why twice so far now.

> the window has only 1 absorbing surface and the panel has 2, one on each side. <

Okay, but the Cathedral Panels are mounted flat on a wall. Even if they were mounted out in the room so they had twice as many sabins of absorption, they're still way too small to do what's claimed. And then they wouldn't be close enough to corners to have much effect at bass frequencies.

> There have been measurements to show that a single Coca Cola bottle can provide 5.9 Sabins absorption (if I remember correctly) over a bandwidth of a bit over .5 of a Hz. <

When you stuff the bottle with insulation to broaden the bandwidth, the absorption at each frequency goes down. These magic panels claim to absorb 100 percent over the full 20-200 Hz range on that ETF graph. Again, this is "new physics" in spades.

> If they're hearing protectors and inserted in the ear canals. <

You're really stretching it pal!

> Surface area and thickness/density of absorptive material alone don't count for all of the effectiveness of a tube trap. <

Yes it does.

> proving that the explanation given for why something purportedly works is false does not prove that the thing doesn't work. <

I can't prove the Easter Bunny doesn't exist either, but that doesn't mean it's likely to exist. In this case the burden of proof is squarely on the vendor, and if those ETF graphs are the best they've got, they have proven nothing other than they don't understand how to use ETF. But it goes further than that because ETF will not produce Before and After graphs like those without a little sleight of hand.

> the only way to find out for sure is to attempt to duplicate the measurements and to see whether or not that can be done. <

You do that and let me know what happens, okay? :->) For now I'm quite satisfied.

--Ethan

This post is made possible by the generous support of people like you and our sponsors:

Kimber Kable

---

[ Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2025, Audio Asylum, all rights reserved ]

---

[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]

---