ASC Tube Traps/ And acoustics in general

Thx for the detail.

I’ve been thinking about using the sonotubes and using radial cutters ti cut diffrebt sized circular holes in one side of the tube: like you reflective on the other side.

I would cut circular pieces of safe and sound ti stuff inside, cap bottom and top with circular pieces of semi rigid comfort board.

Eric’s analysis suggests capping does little sonically, but would keep insulation in place. i’d make a circular wooden base, a little bigger with a routered counter sunk groove fir tube ti sit in, likely use construction glue there and attach 3 wheels, cover with fabric!

In order to reduce bass buildup which occurs at the perimeter of walls and in corners the tube traps do require ‘sealing’.

By ‘sealing’ I mean they need to provide some resistance to the flow of air through the wall of the trap into the internal air cavity during the positive half cycle (high pressure) and then back out of the tube into the room during the negative half cycle (low pressure).

This action is what effectively absorbs the acoustic energy and levels out the bass response. The bigger the air volume of the tube, the lower the frequency it can treat.

If you want the traps to be effective especially at lower frequencies they shouldn’t be completely open but rather provide ‘leaky’ resistance to the flow of air in and out of the tube.

The trap acts like a smoothing capacitor in an AC to DC power supply.

During the positive half cycle where the pressure inside the trap momentarily rises as air moves through the wall of the tube absorbing the positive energy it then, during the negative half cycle when the air in the trap is at higher relative pressure compared to the air in the room adjacent to the trap, moves back through the wall of the tube into the room.

Of course you need enough traps of suitable size to be effective in smoothing out the low frequencies.
A couple of small traps won’t make much difference in treating the low end.

Makes sense to me thx.

It was interesting in Eric’s test little difference, but I would lean towards sealing them!

This might help
www.acousticsciences.com/product/tubetrap-bass-trap/

Of course if someone has the itch for them without getting itchy and near Pheonix there are these

www.usaudiomart.com/details/650037205-4-asc-16-x-48-tube-traps/

The Gik Turbotrap price is attractive, almost too attractive. We don't know what's happening inside the Turbo traps. From their look, I guess there is a wire mesh just underneath the fabric. I suspect it's a lesser design compared to ASC isoThermal design. I'd like to be wrong. Also, the GIK turbotrap "range" is very minimal compared to ASC. One size only. Well at least it exists and is readily available in Europe.

I know it's not tube traps, but I have an 8ft x 8ft x 2ft bass trap immediately behind my monitors (the monitors almost touch the bass trap), made out of pink fluffy type insulation (R19, if I remember correctly). It made a pretty noticeable difference (at all frequencies) when I installed it.

I only bring this up to say that I think any sort of sufficiently substantial (and properly implemented) treatment, whether it be a more traditional pink fluffy bass absorber or tube traps, really can help. I've never used tube traps, but had considered them before I built my bass trap. In any case, I have no reason to believe that these tube traps, if used in sufficient quantity, and in an attack wall type placement, aren't doing a great job of improving sound at the listening position. There's too many people having success with these tube traps for it to be a fluke, it would seem.

I still might DIY some tube traps one of those days, to use as mobile treatment around various instruments to tame reflections getting into mics.

I often wonder how much of the effectiveness of the Attack Wall is just that you have a ton of bass traps, with thick insulation, surrounding you. The cylinder shape provides an air gap that, I’m guessing, increases the effectiveness at lower freq too.

Not surprised at all that you your DIY traps made a big difference. But also, just like you, I figure too many great AE’s swear by the ASC tube traps, so I have to believe they’re legit.

Thomann also have a super cheap tube trap design:

www.thomannmusic.com/t.akustik_tube_trap_bk.htm

If you poke around old threads on GS and PSW, Art Noxon (founder of ASC) would occasionally show up and dump tons of info about how ASC tube traps work. Lot of very high-level stuff that goes way over my head, but he seemed pretty transparent about how they’re designed, and I think he even provided a bunch of tips on how to do a DIY build.

I definitely wanted to try DIY at one point, but eventually said fuck it and just went with ASC.

I wanted to add to the pile of ASC fans. I too didn't want to pay what seemed like a fortune for them but finally relented mid pandemic and got 8 on sale (a touch over $4k in 2020). They work annoyingly well, wish I didn't wait the 10-15 years I knew about them to get them. Completely changed the already decently treated but still problematic cabin we were working in into something I wasn't constantly fixing. Like someone else mentioned, felt like I got new mics. I have no idea how well the DIY tubes would work but the ASC's are awesome! If someone's seriously looking I'd keep an eye on Craigslist, at least here in LA every 6-12 months someone seems to unload their collection, usually for a steal.

No, semi-circle behind the listening position, also inspired by those old 'Attack Wall' pictures. I found a pic of that build out from the 90s and the front wall was already stuffed with pink when I did that experiment: