Sand Filled Bass Traps

[brandondrury]

I've decided that my bass traps I built back in 2005 are a failure and I'm weighing the cost / benefit of various bass trap designs.

As much as I like the idea just buying some real traps or whatever, dumping $3k into bass trapping is big investment. I'm not quite ready for that just yet.

I've watched to many physics documentaries this year to believe there isn't a better way of turning a 125Hz wave into heat that can be done for next to nothing. It seems like there could be a really simple way of pulling this off using junk yard parts.

One design that I'm curious about is this one
Build an awesome bass trap

The sand filled tube design seems like it could be cost effective, but the article says nothing about the effectiveness of such a unit. Some real acoustical analysis would have been nice.

Has anyone used this design? Thoughts?

Brandon

[whomper]

Originally Posted by brandondrury

I've decided that my bass traps I built back in 2005 are a failure and I'm weighing the cost / benefit of various bass trap designs.

As much as I like the idea just buying some real traps or whatever, dumping $3k into bass trapping is big investment. I'm not quite ready for that just yet.

I've watched to many physics documentaries this year to believe there isn't a better way of turning a 125Hz wave into heat that can be done for next to nothing. It seems like there could be a really simple way of pulling this off using junk yard parts.

One design that I'm curious about is this one
Build an awesome bass trap

The sand filled tube design seems like it could be cost effective, but the article says nothing about the effectiveness of such a unit. Some real acoustical analysis would have been nice.

Has anyone used this design? Thoughts?

Brandon

as i recall (but dont recall where)
i saw this being hyped by some architect types
for how they tuned some fancy building/auditorium

takes work
but is cheap wrt materials
but if you have more time than money its the way to go
way to go if you cant predict other methods in advance
they are all pretty much cut and fit try it and see then modify again

[brandondrury]

Oh yeah, one other thing......

a) I don't give a shit what it looks like. If hanging two 8' long elephant dicks in my room solved my acoustics problem, I'd gladly go that route....in fact I may do that regardless of acoustical properties of an elephant penis. (How many times do you get to type that???)

b) THIS isn't good enough. Bass Trap Project His designs look nice. (See A). His waterfall graphs aren't nearly as good as I want. Going from complete shit to less shitty complete shit is not my aim.

While his RT60 is certainly shorter in the low end, his overall frequency response is still a damn mess. If I wanted a dip at 140Hz of 15dB (actually off the charts) I'd just smoke dope and watch cartoons.

Note: I'm not trying to slam the dude who made the traps/webpage. I'm just stating that my demands are greater.

Brandon

[rockerdude]

Those look cool.A nice weekend project.....lol.....Or a 6' tall tower of over lapping sand bags in each corner for that military prison camp look.The sand bag thing might be a good idea because of the angles you could achive and the bag material this could be a killer bass trap, and cheap.I will call it, "Sound bags"....lol.....Not to be confused with Fun bags.......Just a thought.

[brandondrury]

Well, I'm not even positive that the tube trap method works yet. It looks like I'm gonna have to re-read The Master Handbook on Acoustics.

Brandon

[whomper]

Originally Posted by brandondrury

Oh yeah, one other thing......

a) I don't give a shit what it looks like. If hanging two 8' long elephant dicks in my room solved my acoustics problem, I'd gladly go that route....in fact I may do that regardless of acoustical properties of an elephant penis. (How many times do you get to type that???)

b) THIS isn't good enough. Bass Trap Project His designs look nice. (See A). His waterfall graphs aren't nearly as good as I want. Going from complete shit to less shitty complete shit is not my aim.

While his RT60 is certainly shorter in the low end, his overall frequency response is still a damn mess. If I wanted a dip at 140Hz of 15dB (actually off the charts) I'd just smoke dope and watch cartoons.

Note: I'm not trying to slam the dude who made the traps/webpage. I'm just stating that my demands are greater.

Brandon

aaayupppp

the architect hid them in columns that matched his interior styling - think the big exterior columns on the front of some pretentious houses or college classroom buildings only smaller and inside

they worked
and were aesthetically acceptable - if you can stand fake columns inside a fancy buildin g

[Ethan Winer]

Originally Posted by brandondrury

One design that I'm curious about is this one
Build an awesome bass trap

That article is the laughing stock of the acoustics business. Sand has no useful absorption. Even if it did, 10 inches is not large enough to be very useful at bass frequencies.

His waterfall graphs aren't nearly as good as I want.

No kidding. Everyone is a damn expert. Sheesh. If you want cheap, go with the known and proven rigid fiberglass, as explained all over my Acoustics FAQ.

--Ethan

[garageband]

Hey, Brandon! Go pound sand!
How many times do you get to use that phrase any more?
The tube things are just wacky for so many reasons.
I love that a guy put a futon in the corner as a bass trap. I'm not seeing the deficit around 140Hz you spoke of I and looked pretty hard back and forth. I think I saw what you're talking about but it's a little tough to tell if it's there. He also copped to the non-repeatability of his measurements. Doesn't mean the design's necessarily bad. I liked the design, but might go with roughly 60% of the slats. Still nice to have some diffraction happening.

Even gave Ethan and Co. a plug. Nice.

[brandondrury]

Yeah, the sand is out. It occured to me that I had quite a bit of unopened Rockwool left. So I did my manual labor for the month and replaced 8 2'x4'x8" wooden boxes that I'm going to call "failed bass traps" with the unopened packages which are 2'x4'x12" (they compressed a bit by the packaging).

I did notice an immediate difference just by yelling in the room in the 250-500Hz region. I've got some work to do before I test the low end, which I hope to get to today.

Brandon

[Ethan Winer]

Originally Posted by garageband

He also copped to the non-repeatability of his measurements.

Looking again at his waterfall plots they appear useless. He either has something connected wrong with the software, or the measuring microphone was in totally different places in the room for each test. This article (about comparing fiberglass density) shows what to expect with Before and After waterfalls:

Density Report

You can clearly see the relation between Before and After, and see what changes.

--Ethan