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

DNorth · Post by **DNorth** » Fri Jun 30, 2006 6:55 am

I have about 24 4" fibrex panels that I have in ready bags.

In my control room, I have 2 stacked in each corner. I have 2 on each side of the console at first reflection points. 2 Mounted on the ceiling. I also have 3 on the back wall.

I have been seeing many people talkig about gik and realtraps. I have seen people say that the design is much better than just having the panels in a bag.

Should I take down the traps I have now and put some better designed traps up? Or should I do a mixture? GIK bass traps in the cornes, and my current traps for just first reflections and ceiling?

What do you guys think? Are realtraps and gik traps that much better?

DNorth · Post by **DNorth** » Fri Jun 30, 2006 7:53 am

I guess my basic problem is that I have the 4" thick panels with no frame, no membrane. I really don't know what the specific purpose of the panel is. Meaning is it good for broadband absorbtion, decent at lowend, decent at mids and highs....

So my question really boils down to this, should I:

1) Keep the traps how they are, just don't use so many. IE 2 in each corner, 2 on the ceiling, 2 at reflection points on each side, 2 at the back. And one one each side at the top corner of the walls.

2) Leave the current panels in the corners, and get the premade traps to go at reflection points, on the ceiling, and on the walls

3) Replace the current corner panels with the premade 4" thick traps. So buy new ones and place them in the corners, and leave what I have on at reflection points, ceiling, and walls.

It doesn't seem much different to me. But I am no acoustics man.

I hope this clarified my question

David French · Post by **David French** » Fri Jun 30, 2006 8:32 am

Mineral fiber panels wrapped in fabric (such as your Ready Traps and GIK's panels) when placed across a corner are an effective solution to the problem of modal resonance down to about 50 Hz. Below that, the best solution is to build a tuned device such as a panel trap with your particular mode's frequency as the trap's design frequency.

DNorth · Post by **DNorth** » Fri Jun 30, 2006 11:02 am

I'm not really worried about anything blow 50hz.

So, it seems as though a wood/metal frame is purely aesthetic. And the added membrane in gik and realtraps will not provide me with better results than my current bass traps.

If that is the case, then I will save myself $2000 on totally new treatment for my control room

myfipie · Post by **myfipie** » Mon Jul 03, 2006 10:00 pm

I don't think I would retreat the room, but the nice part of our product and the Real traps product is they have a membrane in them so the high end will not be over dampend. As David pointed out our product is pretty effective down to 50hz (as our lab numbers show) but really they shine from 80hz to 500hz best.

Glenn

Scott R. Foster · Post by **Scott R. Foster** » Fri Jul 07, 2006 8:55 am

Glenn:

I think we all appreciate the fact you recognize that the author of the thread doesn't need to throw away his absorbers and send you and Ethan Winer a big fat check.

I’d also appreciate it if you would consider a retraction of your specious and negative comparison of our products with the Ethan Winer
MiniTrap, both here, and at every other internet forum you have made similar false assertions. Specifically I refer to the idea that the MiniTrap is somehow superior when compared with mineral fiber panels upholstered using our RT424B Bass Trap Bags because “high end will not be over dampend [sic]”.

Given that the performance of your GIK 4” panel drops like a rock at 500 Hz I certainly can understand your desire to describe this characteristic as a beneficial “feature” – I don’t agree with you – but I understand. And if you are amenable, I’m willing to just leave that as a disagreement between competitors, as I reckon most folks can ponder the notion that you and I might disagree on that point all that need be without help from me.

But, when you start making claims as to the superiority of the MiniTrap to our product, due to variances in their respective absorptive properties I am compelled to present a scientific comparison so that the market and interested professionals are not left with impressions which I regard as a falsehood.

To illustrate my point please review the graph below. This graph shows absorption measurements for the Ethan Winer MiniTrap, which he has published at his web site – multiplied by 18 [the reason for the multiplication is explained below].

Alongside are measurements for the RT424 Bass Trap which we recently conducted at Riverbank Acoustical Laboratory [RAL] – multiplied by 12.

[A full measurement report containing this data will be available for download on our web site at http://www.readyacoustics.com as soon as we have certified reports in PDF format from RAL – probably next week – let me know if you want me to notify you as soon as it gets posted]

The RT424 is a 4” thick panel of Owens Corning 703 upholstered with the same RT424B Bass Trap Bag mention in the original post of this thread. The RT424B is a plush fabric “bag” used by studio and home theater owners seeking to build Do-It-Yourself [DIY] broadband absorbers. The RT424 Bass trap is the assembled version of the device you have, in my view, unfairly, and incorrectly disparaged.

Please look at the graph below and take note of the following:

i) The RT424 is a superior broadband absorber to the MiniTrap. So much so in fact that in order get the two absorption curves to overlay one must amplify the measurements at a 3/2 ratio in favor of the MiniTrap;

ii) Eighteen MiniTraps and Twelve RT424’s yield extraordinarily similar measruements all the way across the band. In fact, the curves are so similar when expressed in a 3/2 ratio as shown, that the two devices exhibit almost EXACTLY THE SAME absorption measurements at the majority of data points

[MODERATOR'S NOTE: The image was NOT posted in accordance with forum rules. It was linked off-site, rather than being posted directly to the forum. It has now disappeared from the original location: Therefore, the rest of this thread is pretty useless, due to the poster's blatant disregard for forum rules- The reason why the poster chose to link it (instead of posting it), then remove the original from his lined location, I'll leave to your own imagination...]

To put this data in a practical context, consider a studio or home theater that requires broadband absorption treatment on scale equivalent to that depicted in the graph above. To meet his needs a user might either: i) buy 12 RT424’s at a cost of about $1,000 [free delivery]; or, buy 18 MiniTraps for $3,400 [plus delivery costs].

If he opts for the RT424, he gets a set of sharp looking professional grade acoustic panels in the color of his choice, gets to skip hanging the extra 6 panels, and saves at least $2,500 [more if he is on the West coast].

On the other hand, if the +/-3 Sabine per panel variance at 10k bothers him, I would suggest he read up on the absorptive qualities of air at 10k hz, get rid of the throw pillows off the couch and send the band out for a haircut and a shave while he counts his money and bids on a German microphone or some such on eBay.

edit: smaller graphic - sorry

Eric_Desart · Post by **Eric_Desart** » Fri Jul 07, 2006 11:36 am

Interesting to notice are the very old and countless discussions about the effect of a membrane and the traditional high density advices.
Yet unclear is what the difference is between the old original MiniTraps measurements showing a much more enhanced resonant membrane behavior and the current ones.

The above measurement is a plain OC 703 in a nice fabric bag one can blow through, without whatever real membrane (it probably/possibly still shows some membrane effect, depending on gas flow resistance of the bag).

Hence the above graph, if correct, shows 12 standard 4" OC 703 panels
in a bag being +/- equal to 18 MiniTraps with double density fiberglass
AND special dual-layer damped membrane.

Maybe looking at Bob Golds' absorption page is not such a bad idea after all.
http://www.johnlsayers.com/phpBB2/viewt ... ght=#45678

Maybe more accurate comparisons come available in the future, but the above, without discussion, questions some typical net axioms.
Anyhow it's nice to see that more and more real data comes available on the net substituting stories.

DNorth wrote:I have been seeing many people talking about gik and realtraps. I have seen people say that the design is much better than just having the panels in a bag.

Should I take down the traps I have now and put some better designed traps up? ........
Are realtraps and gik traps that much better?

......
I guess my basic problem is that I have the 4" thick panels with no frame, no membrane. I really don't know what the specific purpose of the panel is. Meaning is it good for broadband absorption, decent at lowend, decent at mids and highs....

DNorth
Without minding what brand or choosing the DIY path, just going to the core of things, the above graph, its included measurements and the idea it represents, put such stories in the context they belong.
It's a real pity that people take that over, and spread it further as acoustic facts. Even dedicated Magazine reviewers buy and spread these stories (which I find VERY questionable).

A possible scenario:
Unlike suggested here in the Forum, until finding info to the contrary, general knowledge of the typical behavior of corner absorption is relative recent in the studio world (and even for lots of labs).
Hence a lot of reviewers are confronted for the first time in their live with corner absorption and it's very specific low frequent behavior. Not really knowing corner absorption, they are amazed about the effect related to the strongly improved definition of the low frequencies, based on relative simple solutions.
Comparing that with previous flat to the wall applications, often not even or hardly aimed at, or designed for low frequency treatment, they seem to buy whatever special/magic description, rather than relating the reviewed absorbers and related musical experience to the typical acoustic behavior inherent with corner absorption.
And they hardly can go wrong since they are covered by others, hence this phenomenon multiplies, certainly when activitated by interested parties.

Just compare measurements if you can find them, and preferably official measurement data if possible. And be very careful to interpret values below 80 Hz, because the inaccuracies can be significant (too extensive here to explain). As one will notice you hardly will ever see the statistical values of these numbers which are automatically calculated by labs.

Ethan Winer · Post by **Ethan Winer** » Sat Jul 08, 2006 3:17 am

Scott,

> the author of the thread doesn't need to throw away his absorbers and send you and Ethan Weiner a big fat check. I’d also appreciate it if you would consider a retraction of your specious and negative comparison of our products with the Ethan Weiner MiniTrap <

Yikes - that's some first post you made there. That you haven't learned how to spell my name after all these years says a lot too.

> I am compelled to present a scientific comparison <

Where? What I see are bogus comparisons of product measurements made in different labs. If your aim is to be scientific, I suggest you start by buying the ASTM C423 document where you'll learn about the very large variance among labs, especially at low frequencies.

> The RT424 is a superior broadband absorber to the MiniTrap. <

Groan.

> To meet his needs a user might either: i) buy 12 RT424’s at a cost of about $1,000 [free delivery]; or, buy 18 MiniTraps for $3,400 [plus delivery costs]. <

I didn't realize manufacturer spam was allowed in this forum.

Scott, this fine forum really isn't the place for such posturing. I invite you to call me any time on the phone and we can have a nice discussion about acoustic products, marketing, scientific testing and comparisons, and especially about appropriate public behavor. Please. I'll be around Saturday early morning and late afternoon, and all day Sunday.

Thanks.

--Ethan

Eric_Desart · Post by **Eric_Desart** » Sat Jul 08, 2006 3:58 am

When useful:
http://www.realtraps.com/art_measure.htm

RealTraps / Ethan Winer wrote:US labs that perform acoustic tests are certified by NVLAP, a department of the US Government's National Institute of Standards and Technology. Testing of acoustic materials is defined by ASTM, an international organization that establishes standards and practices used by acousticians and their companies. By ensuring that its members follow exactly the same rules and guidelines, materials tested to ASTM standards in different facilities can be compared with confidence.

When annoying:

Ethan Winer wrote:> I am compelled to present a scientific comparison <
Where? What I see are bogus comparisons of product measurements made in different labs.

No more words needed here:
The above graph, if correct, is clear, and I expect, as told, will be confirmed by an official lab report, which nobody ever saw from RealTraps.
The difference is there, being explicit and present over the whole spectrum range.
Calling this bogus is the same as calling 'Official Accredited US Laboratories', ASTM and NVLAB bogus.

Maybe the notion stories I emphasized falls more in place here (neither responsibility, nor ethics, nor the interest of, or respect for Forum or Site visitors).
Possibly a range of detailed, hardly in context, pseudo-arguments will follow to divert from what this Graph clearly shows.

myfipie · Post by **myfipie** » Sat Jul 08, 2006 5:28 am

Scott

I have ever said anything bad about your "bags" as far as I can remember. I have pointed out you do not have testing as you did point out about our product before testing, but that is not saying anything bad. Hell I am glad guys like Rod pointed it out.
I wish you luck with the company you just bought. Hope we can all get along online and not just bitch at each other.

Cheers,

Glenn

Scott R. Foster · Post by **Scott R. Foster** » Sat Jul 08, 2006 5:38 am

EW: I corrected the spelling of your last name... I apologize, no slight was intended.

The balance of the post is correct and scientifically valid. And it belongs here because a response is appropriate to the false of claims made as to the attriubutes of our products and the Minitrap.

As to your desire to bring your emotional needs into the discussion - I have no interest - you will need to work that out some other way.

Good Luck!

Ethan Winer · Post by **Ethan Winer** » Sat Jul 08, 2006 6:08 am

> The balance of the post is correct and scientifically valid. <

Look Scott, I'm not going to get into a pissing contest with you. If you don't understand why your data comparing corner testing in unknown corners in different labs is not valid, you have a long learning curve ahead of you. Likewise, if you really believe you have invented a magical bass trap that surpasses MiniTraps by 50 percent, nothing I say here will educate you. The same goes for Eric pretending he doesn't understand the difference between official ASTM C423 tests and uncertified tests in corners. But please listen to Glenn, because when you bitch and snipe at your competitors' products you come off as immature and jealous.

--Ethan

Eric_Desart · Post by **Eric_Desart** » Sat Jul 08, 2006 6:58 am

I let Ethan speak (he does it much better than I can, yet it's confusing if one doesn't see the strategy, but I can't help that):

1) Ethan Winer in this thread wrote:> The balance of the post is correct and scientifically valid. <

If you don't understand why your data comparing corner testing in unknown corners in different labs is not valid, you have a long learning curve ahead of you.

2) http://www.realtraps.com/data.htm - Ethan Winer wrote:Both data formats are shown so you can easily compare MiniTraps to other products not listed here, regardless of how their performance is stated.

Both data formats refer to the 'sabins' and 'absorption coefficients' tables, method which BTW is NOT allowed by the ASTM standard and relates to the locked "edge effect" threads (having more depth than realized here).

To prevent confusion: quote 2) is valid for everything inferior, and quote 1) for everything superior. Truth and physics should have some flexibility.

I didn't knew I pretended whatever in this thread, just analyzed. (even don't understand the context of that sentence ..., but please don't explain ....)

Post by **John Sayers** » Sat Jul 08, 2006 10:27 am

From Ready Acoustics site:

What is a BASS TRAP?
Why haven't I heard of a Bass Trap or High Frequency Panel and what is the difference between the two?

A BASS trap is simply a device designed to absorb low frequency sound and enhance your overall sound experience.

Ready Traps use mineral fiber to capture sound waves. The core of a Ready Trap is a panel of compressed fiberglass that is made of inert fibers [glass - which is of course made of sand]. These panels are an assembly of such fibers formed into a dense mat. The panel is riddled throughout with many little gaps and holes [interstices]. The air that fills these little gaps and holes has a vibrational connection to the air in the room - but this connection is attenuated by the matrix of fibers that makes up the panel.

When a sound hits the Ready Trap, the air inside the panel is caused to vibrate - like a spring - and all this wiggling around turns the vibrational energy of the sound into a small amount of heat. If the panel is of proper size and density - and properly placed in your room - it will absorb sound at all frequencies. This is called a broadband absorber because it is effective on all frequencies in the audible range.

Broadband absorbers such as the RT424 are called BASS Traps because they are big enough [4" thick] and made of a material of proper density and structure such that if mounted near a room boundary [a wall, floor, or ceiling] they will provide absorption of low frequencies [bass].

Thinner panels such as the RT422 at 2" thick are not thick enough to have a significant effect at lower frequencies. Thus these are called High Frequency Panels because their absorptive properties are limited to higher frequencies.

Use of the 4" RT424 Ready Trap is appropriate when you want to include low frequencies in the sound absorbed by the device - and the 2" RT422 panel is for when you don't want to capture low frequencies. Many rooms and applications will benefit from the exclusive use of the thicker RT424 panel for all of the treatment locations, but there are special cases where the 2" RT422 are all that is desired. Some of those places may involve voice over booths, voice only studios or places where light acoustic instrumentation is being played or recorded.

That's the most ridiculous description of a bass trap I've ever read. I'll sell you a cloth bag, 4 x plastic corners and two sheets of cardboard that will wrapup a sheet of 703 or rcokwool or what ever you have and we'll call it a bass trap!!

This is a bass trap:

You will notice that the corners where the ceiling and walls meet are in fact ports where the bass buildup in the corners can escape into the cavity above the timber ceiling where acoustic hangers trap and absorb the bass frequencies. That is a bass trap.

A sheet of 703 placed across a corner of a room is NOT a bass trap IMO. It's just standard utilisation of the corner effect of a sheet of 703. Suggesting that adding a fancy bag around it makes it a bass trap is really stretching the concept of a bass trap IMHO. - it's just a sheet of 703 wrapped in a bag.

cheers
john

Scott R. Foster · Post by **Scott R. Foster** » Sat Jul 08, 2006 1:11 pm

Hi John:

What does a bass trap do?