Poly-cylindrical diffuser sound treatment

[jomaco1989]

I'm looking to build some relatively cheap poly-cylindrical diffusers, and so far I have thought of two options:

1) I have sourced some concrete forming tubes that are already cut into half cylinders.

2) I could bend some 3mm pegboard/hardboard (or possibly plywood, not as cheap): a cheap option I thought of was to bend it by attaching wire to holes at either side and then tensioning the wire to bend the material, but in this case it would not be mounted in a frame, which I gather is desirable.

The pre-cut concrete forming tubes seems like a quick option, they are pre-cut and would be easy to put up around the room.

I have read that a Euler-Bernoulli buckled curve, or the ability to make curvatures of different radius, is favoured over cylinder sections - is option 1 worth it if I can't have curves of different radius? But instead half-cylinders e.g. https://www.lifewire.com/make-your-own-audio-diffuser-3134903

FYI. I am not sure of the density of the cardboard material (option 1), but they are 9mm thick and each half-tube weighs ~6kg, so they are pretty bulky things in comparison to the pegboard, the pegboard has holes in it, so not sure if that is a problem. This is my first post, so to introduce the space I am trying to treat, it is 5.5 x 3.75 x 2.2 m. It is currently treated with bass traps and broadband absorption (Rockwool) - this got rid of the flutter echo, but it is now sounding a little "dead", hence my interest in diffusers.

Tempted to get the cardboard half tubes and just try them out. That is if the half cylinder is not substantially worse than an E-B curve. Do you think it's worth giving it a go?

 

[mjbphotos]

Read this thread about small rooms: https://homerecording.com/bbs/gener...oustic-treatment/small-room-acoustics-365127/
Generally, I believe the facts are that small rooms don't really benefit to any degree from diffusors. In a small room, we most often are looking to get a 'dead' sound, because any short reflections are going to make our recorded sounds crappy.
Bass traps and rockwool traps do a lot more than remove flutter echo, they also tame the low frequencies.

 

[jomaco1989]

Thanks, so far I've got bass traps in the corners and broadband absorbers at the reflection points etc. but it seems a bit dead. I will add foil to the front of bass traps and see if that makes a difference, but I suppose the ease of making the above tempts me if it will also add to the liveliness of the room. Cheers

 

[BroKen_H]

Whatever floats you boat. If you think it's worth trying, and there's little expense, why not? I built diffusers for my back wall after I had my primaries and clouds up and I like what it does for the room. My liking it may be because I put a lot of time into it more than any actual benefit to the room...I used square doweling in a pattern...like this: (only mine don't look nearly that nice )

 

[Robert Tielke]

I recently had the chance to do some measurements with such diffusors in Karlsruhe. It showed that 2D-diffusors are an expensive - but well solution for small rooms. In many cases they are the only solutions for this. One guy showed up with a diffusor taken from an engineer's website. It is the lowest image in here:

This suits perfectly also HiFi rooms. It is easy to built but heavy! More than 150 pounds!
Mosaic Diffusor Concepts - J.S. 2002