[drummermitchell]

Wondering if there is any advantage to having diffusion on rear wall if you have bass traps basically covering
most of wall area.
I see Realtraps have diffusion with bass trapping built in.
Say if you have solid wood diffusion in front of the traps maybe an inch or two,would the traps have any effect at all.
Perhaps it's better to have the traps centered and diffusion to each sides of traps.
Or some other way of doing the real wall,thanks.

[Big Red Machine]

Sometimes a straight rim shot is used, but a flam works better.  And sometimes a four stroke ruff is the right answer.  Absorption behind you is not diffusion.  Diffusors do not absorb per se.  Combining them can kill two stones with one bird.  My rear diffusors sit on 6 inches of absorption.  I need both and that is the way to get it done.

[woodsyi]

Diffusion typically operates at higher frequency than what you would consider bass.  You have to go pretty deep in the well depth to operate below 500hz.  If you only have bass trapping in the back, you can probably put diffusion in front of it as they are operating at different frequencies.  If, on the other hand, your back wall traps are absorbing high frequency for the purpose of reducing standing waves than diffuser would block the waves making high frequency absorbers useless.   So, it should be one or the other.   I like a lively sound and prefer diffusion in the back wall as opposed to absorption.  Either is an improvement over not treated rear wall.  Sound stage collapses when I remove diffusion on the rear wall. 

[TomS]

I have 3 RealTraps near diffusors on stands in the back, sitting in front of wall mounted GIK Monster traps. The RealTraps are rather shallow and also have built in absorption (4"?) in the back of them.

[Dave G]

I have 3 RealTraps near diffusors on stands in the back, sitting in front of wall mounted GIK Monster traps.

Tom,

How far behind your chair is the rear wall?

Dave

[TomS]

Tom,

How far behind your chair is the rear wall?

Dave

About 6'

[bpape]

Solid wood diffusion, likely not much from the absorption. If you have something light like EPS, then the bass can pass through it effectively and get into the absorption behind.

Bryan

[drummermitchell]

TomS,that's what I have is two monster traps there now.
If I had solid wood diffusors in front I don't see how the lows could pass thru or even the traps having any effect as the diffusor would have a solid backing.I am about 5' in front of my wall.
How do you like the Near diffusors.

BigR,I like inverted paradiddles with hand+foot combinations .

[TomS]

I'm not sure about the wood in front of them. I'll leave that to the guys here (like BPape or Ethan) who know way more than me.

The near RealTraps work great behind with a little distance (6-8'), though being fairly shallow, they're working at a much higher frequency than the absorbers are.

[Ethan Winer]

I'm not sure about the wood in front of them. I'll leave that to the guys here (like BPape or Ethan) who know way more than me.

It depends on the thickness and mass of the wood. Generally wood thicker than maybe 1/4 inch will reflect too much at bass frequencies to let the waves through to absorption behind.

--Ethan

[drummermitchell]

Ethan, what is the backing made of behind the wells as I have read that they do have some form of bass trapping on the back.
Seems they scatter the highs and absorb some bass frequencies also,
Perhaps using those with the Monster traps would be a good way to go.

[Ethan Winer]

Ethan, what is the backing made of behind the wells as I have read that they do have some form of bass trapping on the back.

If you're asking about the RealTraps diffusers, the well covers are made from a type of rigid card stock. So they reflect mids and highs, but pass bass into the rigid fiberglass behind.

--Ethan

[drummermitchell]

Thanks Ethan,I imagine those combined with additional bass trapping behind the diffusers would have some benefit.
As I have two monster traps there now,hoping I can still use them with the diffusion.
I also imagine if a person is 5-6' away,then the near field diffuser would be best correct,thanks.

[Ethan Winer]

Yes, having bass traps behind our diffusers can only help, though they absorb very well on their own. The Far diffuser has about as much bass trapping as our MiniTrap, and the Near type has almost as much trapping as our 6-inch thick MondoTrap.

For 5-6 feet away you'd do fine with our Far version.

--Ethan

[TomS]

Yes, I think my RealTraps in back are actually the far version 

[Nyal Mellor]

Normally with a QRD type diffuser you are recommended to be no closer than 3-4x the lowest diffused wavelength. That recommendation comes from RPG....its normally here but the link seems to be broken: http://www.rpginc.com/research/TechBullDiffCritList.pdf

[Ethan Winer]

^^^ Yes, and that's about 5-6 feet for our Far diffusers. Though in my experience, you can be closer than that and still get much better sound than from a bare reflecting wall.

--Ethan

[drummermitchell]

Nyal,that link definitely is broken,have been to RPG's site among others.
Somewhere I read that for every inch of the deepest well,say 6",then a diffusor should be 6'away from seating.
Been doing this quite blind as have gathering info from here and from a few companies.
I believe I'm full up with my bass trapping as I did my W/W corners+W/C corners,
first reflections  and of course the backwall(trapped).
As my room is only 12X19X7.5 I'm thinking next and only step left would be rear wall diffusion to try.
I do like the idea of Realtraps where there is bass trapping  already applied,but if you have existing bass traps you can use those behind also.
Kind of a win win as I would like to use what I have instead of having the extra traps and can't use them.
Thanks guys for all the info,now it's a matter of when and if I can sneak diffusers into the house.

[Nyal Mellor]

The best 'close' diffuser I have used is a combination absorber diffuser by RPG - the BAD panel ( the Arc curved panel is even better than the straight), you can sit within a couple of ft and not have any strange effects like you sometimes do with QRD type diffusers. Kinetics also do a product that is similar.

[jk@home]

At the risk of the scorn of the experts here...try some fake ficus plants in front of the bass traps. They will diffuse somewhat (did in the case of my Maggies). And look nicer too.

You can always do real diffusers inboard/outboard of the traps.