John Sayers' Recording Studio Design Forum Archive

Does anyone know or have experienced the benefits of TUBETRAPS, made by a company called ASC? These are bass absorbers that are cylindrical & can be mounted on stands. As such, they can be arranged to suit any application.

I was very excited about this product until I saw the pricing. I think they go for around $370 USD per unit & $2400 USD per set of 8! Then, I had a great idea:

How about: mounting a piece of carpet onto a tripod mic stand, & roll it up until you have the desired diameter, then cover with acoustical fabric for a pro look. Prop it up & VOILA - a home-made stand-mounted tubetrap built to custom height & diameter (depending on the dimensions of your carpet). Probably would cost less than $100 ($30 for a decent mic stand & $30-70 for a good quality carpet).

My rationale is that carpet seems to be widely used for absorption in budget studios, and the 'rolling' process will create layers of airgaps that will trap & eventually dissipate any nasty bass frequencies entering it. This idea is not based on any science, but by my limited knowledge in studio acoustic solutions & some genuine inspiration. Therefore, I seek the wisdom of the forum to comment on the idea.

So I am going to throw a few questions out 2 u guyz:

Can anyone shed some light on the effectiveness of this contraption?

Is carpet a good absorber to begin with?

If I start to get much positive feedback from the forum, I will then attempt to build a set & try them out. But before I embark on a possible wild goose chase, any informed opinions would be greatly appreciated.

Thanx all, 4 reading this long-winded posting!

Ciao 4 now

Well, about all I can do is point you in the direction of this:

http://www.geocities.com/jonrisch/a.htm

The first two links describe a clone of the ASC tube traps.

Now, a lot of folks around here don't think the tube trap design is very worthwhile, although I'm sure they are better than nothing. I still haven't built anything, so all I can do is post links and let them speak for themselves.

Perhaps you should also look at the ASC website to read about how they make them. As for carpet, it is not a good broadband absorber. The whole premise behind the tube trap is not absorption, but also compression and diffusion, like in the attack wall.

The home made units will not work in an attack wall unless they are on stands. I had the idea of just building a simple frame for them to sit on, which would be cheaper than reinforcing them and installing mic stands.

You should read the articles in the ASC page.

http://www.asc-studio-acoustics.com/rs-articles.htm

ASC products did play a prominent role in the making of many records made by Bruce Swedien, for example "HIStory" of Michael Jackson's album.

In the words of Bruce:

"Even so I use my own set of ASC tube traps to tame certain nasty little acoustical "Hot Spots" that remain. Without the traps, it's a just a little too bright with a bit of an edge. With the traps, it's just about right..."

The secret of the Tube traps:

"At the same time, the entire surface of the studio trap is providing bass range absorption, half of the trap is also providing treble range diffusion. The effect becomes clear if the Tube Trap is rotated on axis. As you speak the words "check, check, check, testing one, two, three," the fully absorptive section of the trap sounds perfectly dead as one would expect. Then the surprise. As you come into proximity to the diffusive side of the Trap, the sound becomes bright, fresh, and clear.

This hybrid acoustic is made possible by the suspension of a thin, precisely weighted, and perforated sheet of limp plastic that covers the front half of the cylinder surface. The properties of the diffusor sheet are such as to make it an acoustical crossover, passing low frequencies into the interior but back scattering high frequencies."

The fact is: how can we achieve that thin, precisely weighted, and perforated sheet of limp plastic that covers the front half of the cylinder surface?

If someone has an idea, please tell us.

I recently tried this, only because I had two 8 X 10 ft. pieces of carpet handy.

I was unable to notice any change in low freq. absorption, though only two of my corners are covered...

Because carpet is not a wide band absorber. It only absorbs a few highs and that is it. There is more to it than an absorber on a stick, or Auralex's foam on a stick.

The carpet will never work. Tubetraps are air-tight, hence how they trap the low-freqs, basically trapping it inside the tube... Read all of Jon Risch's stuff on debunking the tube trap. Wrapping carpet and plopping it on a stand is really minimizing what these devices do. Don't know how to say that any nicer...

Tubetraps vs. RealTraps - Realtraps seem to do a better wider low freq range of trapping (absorbing), but you could build either with differing results. The advantage of buying Tube or Real - is that you get a proven working trap, no gambles, no risk. That is what you are paying for - something that will definately do what it is spec'ed to do.


David