[bgewaudio]

Ethan and others, what is your take on abfusors?  Does this kinda give you the best of both worlds?.

[Ethan Winer]

> what is your take on abfusors?  Does this kinda give you the best of both worlds? <

Yes.

For the present.

--Ethan

[woodsyi]

> what is your take on abfusors?  Does this kinda give you the best of both worlds? <

Yes.

For the present.

--Ethan

How about the near future?

Will a pair of DIY 2x2 skyline diffusors (8" max out) benefit on rear wall 10 foot away or would a pair of micros do just as well while taking up less room?

[bgewaudio]

Well, were talking two different outcomes, scattered sound vs. absorbed sound.  Two different effects.

[woodsyi]

Well, were talking two different outcomes, scattered sound vs. absorbed sound.  Two different effects.

Yes, thus the question.   

I have 3 mini, 2 mondo, 5 micro, 4 GIK(4") 4 adapt corners.  I don't want to absorb too much but I want to reduce reflection coming off the back.  Absorb, diffuse or abfuse? 

[Ethan Winer]

> How about the near future? <

Let me look into my crystal ball...

> Will a pair of DIY 2x2 skyline diffusors (8" max out) benefit on rear wall 10 foot away or would a pair of micros do just as well while taking up less room? <

I guess it depends on whether you prefer a room that's more live or more dead sounding. I tend to favor more on the dead side, but a lot of people prefer more live. So there's no one right answer. Though I have to say that the problem I hear with most "too live" rooms is they have no diffusion either!

To me, the Number One acoustic problem is comb filtering. Absorption and diffusion both solve this. By diffusion I mean the QRD well or skyline types. There may be other designs that avoid comb filtering as effectively. I haven't heard every diffusor out there.

--Ethan

[bgewaudio]

Basically, diffusion is used to scatter or breakup first order reflections.  You are still going to get flutter echo with diffusion, but with a reduced amplitude.  So the original sound combined with the time delayed flutter echo will give you a more concert hall ambiance (more reverberant) environment, as apposed to absorption which will omit first orders all together (or hope to), giving you a more laid back/neutral sound.

I am actually going to make an abfuser for my 2ch/HT room consisting of a staggered wood backing with possibly some 703 or equal on the outside with some type of transparent fabric.

I have my fingers crossed.

[bpape]

Also remember that if you're using a well type diffusor, there is some absorbtion inherent in that design.

My issue with diffusion is that you have to be relatively far away from it for it to be truly effective.  Also, for a diffusor to be effective down into the bass where a lot of room related FR issues occur, they have to be huge.  You're just not going to deal with 20' long waves with a diffusor that has a max 8" variation.

I'm not saying they don't have their place - they certainly do.  Just use them for their intended purpose and in the ranges where they're effective - and in combination with appropriate absorbtion for the task at hand and usage of the space.

Bryan

[bgewaudio]

You're just not going to deal with 20' long waves with a diffuser that has a max 8" variation.

This is where the bass traps come in!  if you were to treat first orders with 703 panels on the wall, they would still not be that effective in the lower registers.  That's why traps are used in addition with first order treatments because the two work together to cover the entire frequency spectrum.

[klh]

On the topic of abfusers. Do skyline type diffusors reflect lower frequencies or do they just pass through? If they merely pass through and one has enough room, one could attach skyline diffusors to the front of a very thin pseudo wall behind the seated position. One could also attach 8# mineral wool to the backside of the pseudowall (as thick as you can reasonably go). If the pseudowall was a few feet out into the room, the mineral wool would absorb fairly far into the lower frequencies and the diffuser would diffuse the middle and upper ones. One would need a fair amount of space to do this (10 feet?), but it may just work. In the end, you thwart the low frequency problems associated with bass waves reflecting off the back wall while not decreasing the ambiance.

[bgewaudio]

Kln, your description of an abfuser is basically mine in reverse, never really though of it that way but I think that could also be a reasonable idea.  You see I was thinking along the lines of putting the diffusive material in behind while having more absorptive material on the front, but having the diffusive material in front to treat HF and MRF and then the fibre or mineral wool in behind to treat the LF sounds more beneficial. 

Good for you, thanks for the input.

Barry

[Ethan Winer]

Krister,

> Do skyline type diffusors reflect lower frequencies or do they just pass through? <

It depends on what they're made of. A diffusor made of solid wood or MDF will reflect, but those made of thin stamped plastic or styrofoam will pass what's not diffused. This is a simplistic explanation, but hopefully you get the idea.

--Ethan