Damping Foam options?

[Xanathax]

I am in the process building a TL box.
Found at: Perfectionist Audio Subwoofer
and I hit a snag in looking for the damping foam/damping foam blocks. Any possible substitutes or recommendations? ALL advice is GREATLY appreciated. I have been looking at: Sonic Barrier 1" Acoustic Foam w/PSA 18" x 24"
however i need strips... as described in http://www.nulltime.com/DIYAudio/sub...ages/pg27w.gif please anyone with any possible response, lend me your knowledge. after all, thats what we are here for right?

[Cal Weldon]

I moved this over to the woofer section. I think the response will be better here.

[malibujeff]

You could try some No Rez. It can be cut into strips. You can find it here:

No Rez 24"x27" Sheet - NR-24x27

[Xanathax]

That seems very similar to the sonic barrier foam i mentioned. however i will take all blame for not mentioning why i couldn't use it. the strips are supposed to be 4"x4"x6' which would very quickly get very expensive if i were to use bound strips of such thin materials. After some reading, i have another question. would using such a sheet of material in a vertical manner, rather than following the tunnel, be just as effective in filtering out the high frequencies (which is what i believe this is meant to do). because this is a sub box after all.

[planet10]

Way better than foam would be something like UltraTouch.

I'm not a big fan of foam.

If you haven't actually built the box yet, i have some ideas on how you could do better -- there are a few tricks to make it go lower (12' is too long to get the most bass). I did an amazingly similar design that predates this one, so i am well familiar with the design.

I assume you are using B139s?

dave

[Xanathax]

I like the idea of using UltraTouch, it seems that it would simplify some of the complications i predicted the foam may have. I am also interested in any ideas you may have on the box itself. I have the materials gathered, except the damper, and an open mind. so please, let me know

[planet10]

It turns out that tuning a driver below Fs decreases the bass. As well a line that is tapered needs to be shorter than a straight line to have the same tuning. Also end loading a driver creates the strongest 1st objectionable harmonic. Mounting the driver at an offset, pretty much kills the 1st harmonic, so that you can get away with less damping and less attenuation of the primamry resonance (netting more bass and less ripple).

Given the classic nature of the B139, and an affection for it, by both Scott & myself, we did a modern TL for the B139, It can be seem in a few configurations. I haven't yet morped the design into a side-by-side Fried H syle woofer like the Perfectionist. Because of the offset driver, i isn't as straight-forward as the end-loaded lines, but i have given it some thot (and could be easily pushed into making it into a useable drawing).

A friend built a single of the push-push straight TL (he had to shorten it a bit to fit in the room). He reported exceptional performance/ When he moved back here he abandoned the cheap ply cabinets, has since found 2 more racetrack B139 and we'll be building 2 of the folded push-push boxes.

dave