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window behind monitors.... best way to treat this??

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Re: window behind monitors.... best way to treat this??

Postby bert stoltenborg » Fri Jan 14, 2005 7:56 pm

Hey Brian,

Good post, as always, but about using waterfalls to determine room behaviour, modes, absorption etc: we do this already for years. You know yourself that even the old LAUD software has waterfall capability.
I saw Ben Kok perform waterfall measurements on absorbers in studio's using MLSSA in the late 1980's. Philip de Haan was showing behaviour of damped and undamped 1/4 wave absorbers in rooms in the late 1980's.
BBC used mlssa waterfalls in papers to show modal behaviour in control rooms in the early 1990.

What's so f*cking new about Ethan's "invention"? 8-)
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Re: window behind monitors.... best way to treat this??

Postby Brian Ravnaas » Fri Jan 14, 2005 8:25 pm

bert stoltenborg wrote:Hey Brian,

Good post, as always, but about using waterfalls to determine room behaviour, modes, absorption etc: we do this already for years. You know yourself that even the old LAUD software has waterfall capability.
I saw Ben Kok perform waterfall measurements on absorbers in studio's using MLSSA in the late 1980's. Philip de Haan was showing behaviour of damped and undamped 1/4 wave absorbers in rooms in the late 1980's.
BBC used mlssa waterfalls in papers to show modal behaviour in control rooms in the early 1990.

What's so f*cking new about Ethan's "invention"? 8-)

thanks to the first, ack! to the rest... hee hee

i have a copy of Laud, i've sure never used it to measure a room (more to avoid measuring a room in speaker tuning). I don't know what's new, and it seems that isn't new from your post, but that wasn't the jist of my note, the sum of my point was just that i think the idea has merit, it must if it's used by Philip & the BBC and all, no? how is Philip, to whom i'm indebted for that mercedes experiment.

anyway, nice to see you, Bert, and this reminds me that i owe a reply on the other thing, tonight i'll get it done, curse my forgetfullness of late.

take care,

Brian
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Re: window behind monitors.... best way to treat this??

Postby Ethan Winer » Sat Jan 15, 2005 8:07 pm

Brian,

> I took the liberty of making a couple of pictures reflecting the transmission loss of windows in practice and calculated, and the worst wall imagineable. <

Fabulous, thanks very much for contributing that. One of these days I plan to measure the comb filtering off my large thermal-pane patio door, using ETF and my Carver Sunfire subwoofer that outputs solidly down to below 25 Hz. I think that's the best test of how much a glass door may reduce acoustic interference. But your data (the measured part) is surely the most relevant I've yet seen about this.

> [with a program like ETF] you can observe the behavior of a single mode ... "well it looks like my slab of 703 is definitely doing something on this 77hz mode" <

Exactly.

--Ethan
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Re: window behind monitors.... best way to treat this??

Postby Ethan Winer » Sat Jan 15, 2005 8:13 pm

Bert,

> What's so f*cking new about Ethan's "invention"? <

I don't claim to have invented ETF or waterfall plots, but I never heard of anyone using them to test absorbers at very low frequencies. I visit every acoustics newsgroup and forum I know of, and I never saw anyone mention this solution in any of those places either. Not even at StudioTips where the limitation of reverb room testing has been discussed many times. Perhaps you posted that and I missed it? 8-)

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Re: window behind monitors.... best way to treat this??

Postby Scott R. Foster » Sun Jan 16, 2005 6:57 am

Exactly what has been "solved" by using ETF?
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Re: window behind monitors.... best way to treat this??

Postby Ethan Winer » Sun Jan 16, 2005 6:02 pm

Foz,

> Exactly what has been "solved" by using ETF? <

The vague results from 1/3 octave noise tests, where all activity in a relatively wide band is averaged rather than showing the true detail.

More to the point, either this type of test gives useful information or it doesn't. Who thought of it first (or in my case thought of it independently) is irrelevant. Bert pointed out that someone else did similar tests with MLSSA in the early 1980s. So if anything that confirms the value of such a test, no? Or did that fellow who used MLSSA conclude his tests were useless and gave no information of value?

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Re: window behind monitors.... best way to treat this??

Postby bert stoltenborg » Sun Jan 16, 2005 6:46 pm

Ethan,

I didn't mean it as an attack on you or something.

Read the stuff on the studiotips forum to see that generalizing (is this english?) these measurements is not possible. You are measuring a room/treatment combination, not a treatment.

That's exactly what these "vague 1/3 octave noise tests, where all activity in a relatively wide band is averaged rather than showing the true detail", developed by very intelligent and learned acousticians, try to avoid.

And about using measurements/waterfalls for determining specific effects in rooms, yes, I wrote about that (for what my contributions are worth) several times in the past couple of years. :bouncy:

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Re: window behind monitors.... best way to treat this??

Postby Scott R. Foster » Sun Jan 16, 2005 10:04 pm

Plotting resonances in a waterfall graph is trivial... its been done for years, and ETF is just a cheap way to collect the info, and create the graph.

Three cheers for ETF! I've got it. I use it, I like it. So do a lot of other folks.

:boring:

As to pretending that you had to "devise a new method..." to measure low frequencies...

http://www.ethanwiner.com/density/density.html

Pullllleassse!

ETF comes out of the box with a LF mode... you "devised a new method" in the same sense one discovers "new methods" for cleaning teeth when you use a tooth brush.

Ethan: you are good at explaining complex things in simple ways... a valuable skill... but IMO your inflated ego, your tendancy to take personal credit for the blindingly obvious, and your refusal to account for elements of a process which you cannot control or fully disclose the elements you do not understand makes this noble work at times come off as sheer silliness and blurs the message with utter nonsense. You so often go from being helpful into being misleading.. and this topic is a case in point.

In that, your stated purpose ["...assess the absorption of these materials at very low frequencies"] involves the measurement of MATERIALS, and collecting information on the LF absorption characteristics of a material - EXCLUSIVE OF THE ROOM WHERE THE MEASUEMENT IS TAKEN - is not trivial, and changing the graph used to display the data changes NOTHING about the hurdles to excluding the room from the measurement.

As has been explained to you a dozen times, there is a world of difference between measuring a material, and measuring a room that contains the material. I just don't understand why you refuse to "get it" on this point... and instead pretend you are conducting LF material absorption test when you are really conducting tests on the room[s] in question [with or without various materials added].

Let me put it this way... you've done your tests and published the results on the web... now, using your skills as an "acoustic expert" and your published data, please state the absorption coefficient for the following at 79 Hz in whatever terms you may [absolute, relative, or otherwise]:

3" 701
3" 703
3" 703-FRK
3" 705
3" 705-FRK


Now tell me how this varies for each material at 94 Hz.

Please report these material characteristics exclusive of the acoustic artifacts of the test room... as I want to use your information to choose the proper absorptive material I will use in a different room.

Thanks

:headbang:
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Re: window behind monitors.... best way to treat this??

Postby Hugh Robjohns » Mon Jan 17, 2005 12:35 pm

Foz wrote:Ethan: you are good at explaining complex things in simple ways... a valuable skill... but IMO your inflated ego, your tendancy to take personal credit for the blindingly obvious, and your refusal to account for elements of a process which you cannot control or fully disclose the elements you do not understand makes this noble work at times come off as sheer silliness and blurs the message with utter nonsense.

Oi! Enough already! Foz, Cool it....

I thought we had finally managed to get away from this kind of personal abuse but sadly, here you are starting it up again. For the very last time, PERSONAL ATTACKS OF THIS KIND ON ANYONE WILL NOT BE TOLERATED HERE. DO I MAKE MYSELF CLEAR?

Let's just accept (finally) that waterfall plots do have constructive uses in assessing the effects of treatment of room modes and move on shall we?

Hugh
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Re: window behind monitors.... best way to treat this??

Postby Ethan Winer » Mon Jan 17, 2005 8:22 pm

Bert,

> You are measuring a room/treatment combination, not a treatment. <

I measured how successfully the various absorber materials controlled about eight modal frequencies. As explained in my report, the only frequencies I can test in that room are those that resonate. But within that limitation I am very much assessing how well those materials work, and I would expect an equivalent amount of absorption in any room. I'm sure it's possible to derive Sabins of absorption directly if ETF allowed exporting the data into a form that could be analyzed as data rather than by eye.

> That's exactly what these "vague 1/3 octave noise tests, where all activity in a relatively wide band is averaged rather than showing the true detail", developed by very intelligent and learned acousticians, try to avoid. <

Nobody is saying that reverb room tests are not useful, or that the people who developed the standards are less than super experts. However, those reverb rooms are not intended to measure reliably below 100 Hz. You can't even use them for relative comparisons, which is was my goal. This is what my tests accomplished. Are my tests perfect? No, of course not. But do they yield useful information not available at any price from a lab? You bet they do!

Anyone who doesn't want to use my data to help them decide what materials to buy is welcome to ignore it! :smirk:

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Re: window behind monitors.... best way to treat this??

Postby Eric Desart » Mon Jan 17, 2005 10:35 pm

Ethan Winer wrote:I measured how successfully the various absorber materials controlled about eight modal frequencies. .........

But within that limitation I am very much assessing how well those materials work, and I would expect an equivalent amount of absorption in any room.

......... You can't even use them for relative comparisons, which is was my goal. This is what my tests accomplished. .......... But do they yield useful information not available at any price from a lab? You bet they do!

Anyone who doesn't want to use my data to help them decide what materials to buy is welcome to ignore it! :smirk:


This is well meant and in the interest of the acoustic community.

Ethan you once more ignore the complete thread about this at Studiotips, while you know any single letter written.
You caused the thread to be born, and followed it to learn.

Experienced people who know how to interpret your page will not use it.
It are the ones, with less experience who blindly trust what you say/write which have to suffer for it.
You failed to make valid comparisons, and thereby mislead page visitors.

This is extensively explained in this thread which you know very well:
http://forum.studiotips.com/viewtopic.php?t=1348

Acoustically your comparison is wrong/misleading and publishing it as such is irresponsible.

And the moderators may believe this is personal, but for me this is a very damaging page, which mainly hurts people depending on, and trusting the assumed knowledge/responsibility of others.

And I think it can be interesting for other ETF users too to check the impact in function of the relative y-axis scale which make comparisons in certain situations VERY to EXTREMELY questionable.
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Re: window behind monitors.... best way to treat this??

Postby Scott R. Foster » Mon Jan 17, 2005 11:02 pm

No thanks Hugh:

The debate is NOT as you state on the question of whether waterfall plots are useful... or whether ETF is useful [wonderful product IMO.. I've been reccomending it for years]. No, the discussion centers on the claim that LF absorption test can be done at home with ETF. That claim is explicitly propounded at both here at this forum, in articles in you magazine, and followed up on at Ethan's web site where results are published arising from "new methods" Ethan has "devised" which purport to show comparison measurements of the materials that are useful in understanding the intrinsic attributes of these materials.

This is FALSE, and the fact you don't have a problem with that speaks volumes.

PS to Ethan: I'm still waiting on numeric responses on the absorption characteristics of 701, 703 and 705 interpolated from your "new methods" of LF absorption measurement.

:headbang:
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Re: window behind monitors.... best way to treat this??

Postby Ethan Winer » Mon Jan 17, 2005 11:36 pm

Eric,

> you once more ignore the complete thread about this at Studiotips <

And you once more ignore the intent of my tests and their value for relative assessment of materials. If you don't think my tests are useful even for relative assessment, that's your choice. But I probably speak for a lot of people when I say the constant complaining about Ethan, here and elsewhere, is becoming quite tiring. And it surely contributes nothing to anyone's understanding of acoustics.

Image

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Re: window behind monitors.... best way to treat this??

Postby Eric Desart » Mon Jan 17, 2005 11:50 pm

Aren't you the one claiming always to stay on topic?
This is not about opinions or finding but about facts, measurement techniques and acoustics.
Neither absolute, NOR relative is this page correct.

Anyhow interested people can read the thread, including real and substanciated arguments.

Thanks for showing yourself.
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