Already have home made traps should i buy some pre-made now?

[nukmusic]

Hi!
Can you explain to me, please, what '8"' in '8" Mid Bass' means.
Thanks. -- Mario

man they are too busy trying to see who's BALLS are the biggest...LOL Just pray that neither one posts any photos..... [/quote]

[Ethan Winer]

Glenn,

> I never said anything bad about your product. <

Nether did I. It makes you wonder what point these guys are trying to make.

--Ethan

[scottdru]

Hi Scott,

I'll go in depth in a later stage, on your extensive very valuable post as 'objective' outsider/new member.
Nice to see that you 'accidentally' dropped by.

Hi Eric,

Nice to see you too. I do have to ask, though, given the speed with which you managed to compose this reply and three PMs after I posted this reply (literally within minutes), how da phuk did you read that incredibly long post so damn fast and still comprehend it all to a level that you could feel confident to level the kinds of accusations you spit in my direction in the PMs? As I said in my PM replies, I think you should know me better than that by now. But I'm hoping that by now we've (at least) sorted through that in our PM correspondence?

In-between:
My messages in the beginning showing those contradictions are NOT out of context, and are representative for a systematic behavior of RealTraps over the years.
It's exactly like readers read, and interpret it. And how they are guided to do it.
Since you refer, seemingly with related insight, to ASTM you certainly know that the use of "Sabins" and "Absorption Coefficients", to which my, as per you, "out of context" quoted RealTraps' text refers, is NOT allowed as per this same Standard? Or is this also "Out of Context"?

Actually, Eric, that wasn't what I was referring to. But . . . fair enough. I wasn't specific as to which particular quotation I was referring to. I'll have to go back up and grab it and point out to you in my next post what I meant I actually hadn't meant to bring up that issue in that particular post . . . just kinda wanted to go in there despite my protests that it should really wait for later.

The first question marks related to uncertainties and differences between labs (based on a complete out of context incorrect misleading example to substantiate it) on the RealTraps site, on another page are DIRECTLY related to the appearance and publication of the GIK materials, being annoyingly high.

I think I know of the first bit of out of context, misleading data/example you are referring to but, if we are thinking of the same thing the jury's still out for me as to who took it out of context in the first place. Was that the results of the testing done by Auralex that you guys had on the Studiotits site? Or are you talking about something different? Please clarify. Also, I'm not sure what you are referring to regarding the publication of the GIK materials and how it's directly related to whatever else it is that you are referring to. Please clarify on this issue as well?

Since I've made the mistake of wading into this one (against my better judgment at the time -- Crikes I'm an idiot sometimes!), I might as well know what we're talking about since I'm clearly going to have to either put some work into defending my statements here or admit to being wrong.

There is no way, that you can explain this difference from 12 to 18 by this page filling and uncertainties in lab measurements.
I know about those uncertainties very well. I discussed them from years ago.
And there is a physical logic behind it, which is more complicated than the simplified approach of John, who made it seemingly a hobby now to degenerate corner absorption.
And as I said in this thread I don't understand the current MiniTraps measurements completely, but I come back to that as well.

I'm all ears. As I said in my original post, if there are better scientific explantions to either support or refute any of the statements I made or theories (of my own) that I detailed above, or that might lend some clarification with regard to a number of the questions I raised above or that others in this thread have raised, I'm happy to be educated further. That's why I come to these forums -- to learn and to be part of facilitating that learning for others. I'm most interested in clarification, even if in the end something I save is proven wrong. I say that with all sincerity, and without any sarcasm.

I must admit, however, that I do have one particular self interest in mind. I have a strong ambition to at some point get to the bottom of all this and find some golden mean of truth (despite the best efforts of both parties) so we can be done with all these flame wars that come up between you guys and Ethan, so we can all have a bit more relaxed time of it on acoustics forums everywhere, and just get on with the business of talking about the important stuff instead of the personal vendettas, etc.

I should also disclose this is part of a warm-up exercise for me. I've come up with a plan that I feel will solve the Israel-Palestine conflict. I'm really excited about it, and feel quite optimistic. So my plan is to tackle that issue immediately after I find a way to resolve the Eric/Studiotits vs Ethan conflict. I figure after I accomplish this one, the Israel-Palestine will be a walk in the park.

Can you show the data showing that RAL systematically measures higher, and IBM systematically lower, since that's noted on RealTraps's site as common knowledge, and you confirm that here.
If you show data I count on the fact that you leave them in context can I?
If clear and significant in order to justify this noted: "common knowledge", I'll certainly will check with them, referring to your data and RealTraps site.

As I stated quite plainly in my previous post, I do not have this data in my possession at this point -- though I'm quite sure I do indeed remember seeing it at some point. This is why I asked Scott if he had the data to which I refere, or at least the data to support his claims that the difference between the labs is within a 3% tolerance.

Perhaps what we need to do is go back and request the supporting data for the ASTM E.33-05 Committee's round robin tests. At this point I care less about who is right and who is wrong than just settling the argument once and for all. Seriously. If it would put to bed some of the angst that has come out of this over the years, maybe we could all breathe a little easier, fer fekk's sake?

[scottdru]

That was 2-1/2 years ago, talking about something from a year before that, and I was wrong. At that time I did not understand by how much lab tests really can vary. However, you didn't know that then either. But this is beside the point because what really matters is what we all know now, not what Ethan thought was true 3-1/2 years ago. Hopefully, you've learned some things in the past 3-1/2 years too. I'll have more to say about what we all know now below.

I have to agree this point. From what I've seen of the history of this feud, each of Eric, Scott and Ethan now hold different positions on certain issues than the positions they held several years ago. I could very easily (if I really wanted to spend the time, effort and emotional energy) to go back through all those old threads and pick out various things each of you guys said that are contradictory to what you say now. If I wanted to call any one of you to account, based on various posts over the long history of this feud, for obsessing over semantics to the detriment of, or utter distraction from, the important scientific facts of the various arguments you've had over the years, it could very easily be done.

Each one of you has learned things and grown in your understanding of some of the important issues through all of the arguments over these years, and others of us have grown with you . . . but what a painful process it's been!

It really doesn't have to be this painful! But, unfortunately, most of the time there is a lot more interest in finger pointing, etc. . . .

> if you've got problems ~250 Hz and below, put more MiniTraps in the room corners. If you've got problems in the 250-500-700 Hz range, put more MiniTraps on the walls. If you need more HF absorption, use HF MiniTraps <

Exactly, and this points up a big problem for the Ready Bags guys. They have only one style of absorber, so of course they're going to either 1) pretend theirs is the single best choice and both standard and HF versions are not needed, or 2) try to make it sound like theirs is as good as a MiniTrap, or 3) continue to insult me as they've done for four years now to convince people I'm incompetent to sell acoustic products. It's a lose-lose all around for them because they can't have it all three ways at the same time! Either Ethan is an idiot and MiniTraps suck but Ready Bags are great, or Ready Bags are just as good (stunningly similar) as MiniTraps. But that makes Ethan a visionary instead of an idiot. Oops!

As I call bullshit with Eric and Scott, I have to do the same here with you as well, Ethan. You aren't doing yourself any favours here, particularly with regard to your assertion that the Ready Acoustics bags offer a single type of absorber.

As Scott F mentioned earlier, it ain't rocket surgery for someone to toss some 703 with kraft paper facing into those bags, or to use some other material as a scrim/membrane. In actuality, it does potentially offer a quite flexible solution if somebody is willing to put some extra effort beyond just stuffing some standard 703 in the bag.

I should also point out that even a standard 703 panel wrapped in fabric is going to have a different response curve if it is mounted flat on a wall that it will if it is straddling a corner. So from that standpoint this kind of trap isn't necessarily any more or less a one trick pony than a standard MiniTrap or any of the other RealTraps panels.

So, as I said, this was not exactly the best argument you've put forward.

As to whether the 703 Ready Bags panels and the MiniTraps have such incredibly similar absorption properties if they were tested to ASTM C423 standards in the same lab, I will await actual test results for judgment on that.

[Ethan Winer]

Scott,

> As I call bullshit with Eric and Scott, I have to do the same here with you as well, Ethan. <

ROF,L. My intent wasn't to bullshit anyone. If Scott said that earlier, I must have missed it. Yes, someone could stick FRK-faced fiberglass into a Ready Bag as easily as they could stuff plain rigid fiberglass. However, whether that would then make the combined "membrane" too heavy to work well remains to be seen. I've done a lot of experimenting with membranes of all types and thicknesses, and I've seen them make things worse as often as make them better. Perhaps Scott & Co. should test that too?

Meanwhile, all of my other points remain unchallenged.

--Ethan

[Ethan Winer]

Nuk,

> they are too busy trying to see who's BALLS are the biggest. <

Indeed. I'm glad to concede that one. Heck, I'll be 58 this year so mine are already pretty shriveled.

--Ethan

[myfipie]

tmi

[scottdru]

Scott,

> As I call bullshit with Eric and Scott, I have to do the same here with you as well, Ethan. <

ROF,L. My intent wasn't to bullshit anyone. If Scott said that earlier, I must have missed it.

He said it in his post here

[scottdru]

tmi

Word.

[Eric_Desart]

I have to agree this point. From what I've seen of the history of this feud, each of Eric, ......, ....... now hold different positions on certain issues than the positions they held several years ago. I could very easily (if I really wanted to spend the time, effort and emotional energy) to go back through all those old threads and pick out various things each of you guys said that are contradictory to what you say now.

Show me some or various examples, where I expressed a clear point of view, contradicted by myself now. I'm not interested in examples from others.

You give me a hard time now, and that's not at all related with acoustics, I've trouble with my own principles now, fighting myself.

[z60611]

Mario Petrinovich:

The 8" refers to a measured design I have lying around here somewhere (the design, not a trap).
The '8"' is just a memory aid for me so I can find it.
In this case it's a device that's about 8" deep, but I don't recall off hand if it's helmholtz or membrane.

[Mario Petrinovich]

Mario Petrinovich:

The 8" refers to a measured design I have lying around here somewhere (the design, not a trap).
The '8"' is just a memory aid for me so I can find it.
In this case it's a device that's about 8" deep, but I don't recall off hand if it's helmholtz or membrane.

Ok. -- Mario

[John Sayers]

I suppose what this really boils down to is the accuracy of acoustic measurements.

I remember back in the 70s when EQing monitor systems was the rage but after having EQ'd my monitors 4 times and got 4 different readings that all sounded different I threw the EQs away. In fact if I found myself working in a studio that had EQ'd monitors I always asked them to bypass them much to the surprise of the studio owners.

the fact that Insulation has more effect on Low end as you move it off the wall was mentioned in my "How to Build a recording Studio " (later to become the SAE handbook) site back in '98. In 2000 I demonstrated the use of a membrane over the insulation to retain high end in Left Bank studios, a practice I still use as it works, so I was not surprised to see Ethan come up with a similar idea in his new minitraps as loss of top end is one of the problems associated with using lots of exposed insulation. That's why I use slots as they retain and diffuse the high end.

The only thing I can see that has come out of this ongoing argument is the strange peak in corner absorption measurements and it's obvious to me that a standard method for measuring corner absorption must be devised immediately because I'm naturally suspicious when someone claims a measured absorption coefficient of 3.00 at 100hz with a piece of 4" 703. I suspect even Owens Corning Engineers would be a tad confused by their product producing those figures.

All you guys are offering simple, but different, systems for the general consumer. Ethans are more complex to manufacture and ship and are therefore more expensive, makes sense to me. He has also been selling his product for years now and like "coldpower" is still recognised as the best cold water detergent because it was the first, so is Ethan's product recognised world wide.

I'm beginning to sense that all this argie bargie being stirred up, yet again, is an advertising ploy by the other manufacturers using this site and others to flog their products under the guise of "bringing the truth about minitraps" to the punter.

I have no problem with you all pushing your products on my site but it's time to put this argument to bed guys - nothing is being achieved other than demonstrating, once again, the inconsistencies of acoustic measurements.

cheers
john

[Eric_Desart]

The only thing I can see that has come out of this ongoing argument is the strange peak in corner absorption measurements and it's obvious to me that a standard method for measuring corner absorption must be devised immediately because I'm naturally suspicious when someone claims a measured absorption coefficient of 3.00 at 100hz with a piece of 4" 703. I suspect even Owens Corning Engineers would be a tad confused by their product producing those figures.

You're not speaking about a 4" panel but corner absorption of a 6" panel on a 1.5" spacer.
That has no absorption coefficient of 3.0, but is noted by GIK as such in analogy with RealTraps, which is not allowed by the standard.
But GIK gives access to the official report which only shows Sabines, NOT absorption coefficients

This thing has no absorption coefficient, measured by the lab. The lab should even refuse to mention those absorption coefficients in a normal official Lab report.
That absorption coefficient is a by the standard NOT allowed poetic license.

You're low frequent not looking to a 6" panel absorption itself but to a narrow high Q resonant piek absorption. That absorber works low frequent as a (by the device self) tuned relative narrow band resonator. The wool itself is part of this absorber, not the absorber in its entirity.

OC should say (in this case it's not OC but high density 8 pcf wool): We have no idea because this is a discrete object where this peak is defined by another phenomenon.

The standard very well defines when an absorption coefficient is applicable and when such objects must be treated as discrete objects, which relates to the edge effect threads.

Eric

[Scott R. Foster]

I suppose what this really boils down to is the accuracy of acoustic measurements./quote]

John:

If Ethan and Glenn post full lab reports the mystery will vanish as % uncertainty for each 1/3rd octave frequency band measured in each of their tests will then be public knowledge.

Want to make a little wager on what those numbers are from 500 to 5,000 Hz?

PS: Glenn's false assertions as to our products apply just as inaptly to DIY mineral fiber panels [which was the original question in the thread]. If you chose to view that as a spat between manufacturers - so be it - it is false nonetheless and should be corrected, and it seems to me that any venue meant to provide a place for the public to gather and share knowledge of acoustics treatments will suffice as a proper forum. Why not this one?

I think this forum is a perfectly suitable place to host a discussion that advances the general understanding of upholstered mineral fiber panels for the many thousands who have made such panels, and also those who are currently considering doing so. If that is not a correct judgment on my part, please correct me and I will advance the discussion somewhere more appropriate.

PPS: The 3.00 absorption coefficient you make reference to does not exist. The fallacy is that you are trying to look at it as a material property as opposed to the functioning of a device.

First, there is no such thing as an absorption coefficient for a discreet object. Discreet objects such as a corner mounted panel or a theater chair are measured and reported as Sabins per frequency band per unit.

I direct your attention to section 4.3 of ASTM C423 . You can get the current edition here:

http://webstore.ansi.org/ansidocstore/p ... 23%2D02ae1

Once you get the concept that an upholstered MF panel in a corner mount is a device it is easier to understand that absorption peak you are referring to arises from the fact that the device operates as a broad Q resonant system at or around 100 Hz. The material itself has no such absorption peak as an intrinsic property.

This peak can be controlled to a surprising extent once you understand its causes. We have done extensive testing at RAL on how to control this peak in both center frequency and in amplitude and will publishing details at a later date.

==============================================

Ethan:

No need for either of us to be there... send the traps and I'll pay RAL to test them. I'll give them the following written instructions along with the fee.

Dear RAL:

Please test the MiniTraps you are in receipt of exactly as you conducted our RT424 corner mount test. Same mic position, mic height, mic boom tilt, mic boom radius, sample placement, sample mounting... in short, do everything exactly the same.

Also, please do not conduct the test at a time when anyone but RAL staff are at the facilty and please make a note of that fact in the offical report.

Thanks,

Couldn't be easier or more fair.

Send along your shriveled balls and I'll pay to have those tested as well.

==============================================

Glenn: Please make sure your web guy gets full copies of the reports posted - all 5 pages - thanks.