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RE: Aye, cynical I am

Posted by Jon Risch (B) on October 21, 2009 at 20:23:52

In Reply to: RE: Aye, cynical I am posted by Ethan Winer on October 21, 2009 at 07:29:51:

Ethan wrote:
"I didn't link to my company's site, I linked to my personal site. Just as you link constantly to your personal site."

A: OK, you are correct on this, I saw the link to www.ethanwiner.com, and thought it was a link to a subset of your retail site. I also thought that www.ethanwiner.com had links to the retail site. I was wrong about that, and I apologize for the misunderstanding.

However, your comment that: " You delete my posts because you don't like what I have to say about the science of acoustics. " is wrong, it was a misunderstanding, which I do regret, for the simple reason that it does give the impression that I was somehow after you personally.

I am completely in agreement that science should be the basis for acoustic absorbing devices, but as Mark Twain once said: "There are lies, damn lies, and statistics." Science too can be slanted or manipulated to present one POV or another in a more positive light, simply by the omission of certain information, or the failure to disclose all of the conditions of a measurement or experiment.

Ethan wrote:
"Jon, that's a lie and you know it. If you can find one place where I said tube traps are worthless, I'll send you $1,000."

Later he wrote:
"We measured two 4-foot high by 20-inch tube traps in the certified reverb room at IBM's lab, and the tube trap had 4.70 sabins of absorption. Now, compare that to your claimed anonymous source of 14.9 sabins for a 20-inch tube only 3 feet high, and you'll see why I call BS."

So you didn't come out and say the words that you thought the tube trap was worthless. But in this very post, you make claims that first, the data I posted was BS, and 2nd, that the absorption of a 20" tube trap is only 4.7 sabins. Isn't that, in effect saying that the tube trap is worthless compared to a panel? Especially since you claim much more than that for one of your 2 foot by 4 foot panels?

Let's look at YOUR claim in a little more detail.
1st, the data I posted in the first section of my post, was, as I clearly stated, from "The Master Handbook of Acoustics", 3rd Ed. by F. Alton Everest, on page 413. As I noted, this data is not the same as the data shown at the ASC website, as it is shown for an entire 3 foot trap, as opposed to the data at the ASC site, which shows the absorption in Sabins on a linear foot basis. Thus, the data at the ASC site would have to be multiplyed by 3 for a 3 foot trap, 4 for a 4 foot trap, etc.

The data in the "The Master Handbook of Acoustics" is not identical to that at the ASC site, even after this multiplication has been performed, thus my belief it is a third party measurement.
I do not know for sure that it is third party data, but in order to dismiss this data, you would have to essentially be dismissing Mr. Everest and his book. While some folks might be inclined to go along with your hand-waving attempts to dismiss me, I think they would have to think twice before doing so with regard to Mr. Everest.

I also note that the data for the 20" cylinder trap is the same as the data for the 16" trap, I went with the same data for the 20" tube trap, so I wouldn't be using the ASC data. I don't think that is an unreasonable assumption, or an unreasonable extrapolation of one set of data to another. It also happens to jibe closely with a set of data for the ASC traps I got off of an acoustics forum some years ago, but that particular site is no longer available.

In any case, you do not cite what frequency this 4.7 sabins represents.
If it is 63 Hz, I thought that you just said that no labs were certified for such measurements?

This would be poor performance in the low bass, if true. But it doesn't jibe with what we DO know about the tube traps, if we just stop and think one minute.

If we allow that the data in the "The Master Handbook of Acoustics" is even close to correct, then how could the 20" trap have so many less sabins of absorption than the 16" trap? Mr. Everest says that the 16" trap has 14.9 sabins at 63 Hz. You say that at some unidentified frequency, a four foot high 20" diameter trap is only 4.7 sabins.

Let's look at another aspect of the 20" trap. Even if it had only a 1" thickness of high density fiberglass in it's cylindrical shell of absorbing material, then via it's circumference and a height of 3 feet, this amounts to a surface area of 15.7 square feet. The surface area of one side of a 2 by 4 foot panel of fiberglass is only 8 square feet.
A four foot tall 20" diameter tube trap has 20.94 sq. ft of surface area.
Not like the tube trap is lacking for sheer material, so the 4.7 sabins is sounding pretty unbelievably small at this point.

Ethan wrote:
"I won't say you lied about the data you posted, but it's clear you do not understand how acoustic products are measured."

A: I'm not calling you a liar, but you must be stupid? Isn't that cute.

I understand perfectly well how the acoustics products are typically measured, but more importantly, I know how they are actually used, and what the results will be in a room.
I intended to cover some of this in my other posts on bass traps, and will.

But wait, Ethan wrote:
"So I'm pretty sure I'm not the one lacking credibility here."

Well, so much for acting like a gentleman and talking about science and acoustics from Ethan. He plays the authority card, and wants us all to know how many articles he has written.

I am not exactly a back-woods hick when it comes to acoustics. I earn my living designing and voicing pro loudspeaker systems. One of the more recent projects I headed was the Peavey Versarray 212 and 112 modular line array systems. The Versarray 112 recently won an award from Live Sound International magazine
See:
http://www.prosoundweb.com/article/the_envelope_please_meet_the_winners_of_the_2009_readers_choice_best_produc/P2/

I designed the very well regarded Versarray 118 and 218 subwoofers, and the 218 utilizes the patented UniVent air exchange vent cooling system, US patent #6,549,637, my invention. It is a unique and fundamentally new way to utilize a vented cabinet to cool the speakers, as well as to linearize the speaker.

So I am not exactly a klutz when it comes to acoustics either.

So far, you have one undocumented, private number that you have thrown out as your proof.
As near as I can tell, there is no data currently given on Tube Traps at your web site either. I recall that you used to have such data, but then, you probably don't want to talk about that either.

I think that folks will just have to keep in mind that I do not sell or make any monetary gain from acoustic absorbing devices, nor does the company I work for. On the other hand, you DO sell acoustic absorbing devices, and have a particular POV to defend, as well as a vested interest in trying to show up competing products. The ASC tube trap is a competitor, and sales of these devices, or DIY builds of them, WILL directly impact your products sales.

I am not going to continue a "back-and-forth" with you on this subject, I think that it will lead no where, and be counter-productive.

I will continue with my series of posts on bass traps versus simple wall panels, and call a spade a spade. I hadn't intended to directly mention you, your products, or your company in those posts, and still don't.

However, if you continue to attack me, or keep posting very questionable "data", then I may be forced to respond to some of those particular instances, if nothing else, to keep the real truth from being obscured or covered up by a smoke screen.

Good day,

Jon Risch

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