Custom DIY diffuser panels...

[Sonnie Parker]

So I posted an update on the differences... I won't dupe them here, but you can see the ETC graph comparisons here:

MartinLogan Renaissance 15A Speaker Measurements and Room Influence

I may do more later... it's quite the task building them. I could do another set for the side corner, but I'm not sure it would be worth it. Everything I do is for two-channel. I'm not all that concerned with movies at this point... never have been outside of doing Dirac Live.

www.avnirvana.com

I'll admit... I did not have my initial ETC and Impulse graphs set properly... I don't think. There appears to be more of a difference than I originally thought... I think... maybe... perhaps.

 

[Sonnie Parker]

Here are the custom absorption panels I built this afternoon... 91" tall x 44" wide x 7.25" deep... with the heavy Roxul R30 insulation.

 

[pratul]

Looks very well made! Can't wait to see a before and after REW analysis.
BTW: I don't like you any more You are an Alabama fan My son went to Auburn.
Just kidding

 

[pratul]

Here are the custom absorption panels I built this afternoon... 91" tall x 44" wide x 7.25" deep... with the heavy Roxul R30 insulation.

View attachment 42046

View attachment 42047

BTW: Are you going to cover the back side of the panel to stop fibers from falling out?

 

[Sonnie Parker]

BTW: Are you going to cover the back side of the panel to stop fibers from falling out?

Probably not... if I leave them there, shouldn't much fall out, if any. The good thing is it's not fiberglass. When moving them into the room and bouncing them around, nothing fell out that I could tell.

 

[Sonnie Parker]

 

[ddude003]

Very interesting... 7.5 dBFS difference... Diffusion is a little wild and crazy... Absorption a little more reserved...

Which one sounds better to your ears?

 

[Sonnie Parker]

Really hard to say at this point. I can't auto switch them, so it's somewhat difficult for me to say one is better than the other... they both sound good. Both image well and have that big sound stage.

 

[ddude003]

I know... Sometimes we can't tell a difference even when REW shows you the difference... And sometime we can hear a difference even though REW can't show us the difference...

Have you tired both??? The absorber over the diffuser??? That might prove interesting too...

By the way... What amplifiers are you running now???

 

[Sonnie Parker]

The absorption panel is covering the diffusor right now.

 

[Sonnie Parker]

By the way... What amplifiers are you running now???

Sanders Magtechs

 

[ddude003]

Sanders Magtechs

Lucky dog...

 

[ddude003]

Sanders Magtechs

When will we get to read your review of these you Lucky Dog?

 

[Sonnie Parker]

I working on a measurement system now... maybe once I get that done I can do some objective reviews of amps, and my personal opinion of them.

 

[Trdat]

I was looking for Arqens build plan on this type of diffuser the other day and it's disappeared off the net. Do you have specifics? Just a basic outline on each depth and height? What program did you use to design it?

Secondly, do you have any reason to place them behind your speakers. Would the diffuser receive either reflections or direct sound at that point?

 

[Sonnie Parker]

I was looking for Arqens build plan on this type of diffuser the other day and it's disappeared off the net. Do you have specifics? Just a basic outline on each depth and height? What program did you use to design it?

Secondly, do you have any reason to place them behind your speakers. Would the diffuser receive either reflections or direct sound at that point?

Yes... the first post as the measurements to use. I used 1x4's and plywood as described earlier. There was no program to design it... it was already designed... see first post in this thread.

I placed them behind the speaker because I have dipole electrostatic MartinLogan speakers that produce direct sound towards the rear. However, I prefer the absorption panels (again, shown in this thread) over the diffusion panels in my room.

 

[ddude003]

Ask Tim Perry on his Arqen web site http://arqen.com/wp-content/docs/diffusers/Diffuser-A1LF-Fab-Drawings-Arqen.pdf or Search for Tim Perry's thesis... https://fdocuments.in/reader/full/acoustic-diffuser-optimization-arqen-copy

Google is your frenemy...

 

[Trdat]

Yes... the first post as the measurements to use. I used 1x4's and plywood as described earlier. There was no program to design it... it was already designed... see first post in this thread.

I placed them behind the speaker because I have dipole electrostatic MartinLogan speakers that produce direct sound towards the rear. However, I prefer the absorption panels (again, shown in this thread) over the diffusion panels in my room.

Apologise, yes on your initial post has a pretty detailed layout of the build thanks.

I don't know much about the Martin Logan's wasn't aware they radiate backwards, now that I know it makes sense. Very interesting about you preferring the absorption perhaps your room is very small? Do you know the average time gap from the speaker to the diffuser then back to the listening position?

 

[Trdat]

Ask Tim Perry on his Arqen web site http://arqen.com/wp-content/docs/diffusers/Diffuser-A1LF-Fab-Drawings-Arqen.pdf or Search for Tim Perry's thesis... https://fdocuments.in/reader/full/acoustic-diffuser-optimization-arqen-copy

Google is your frenemy...

Thanks so much for the link.

The plans do not exist anymore, It seems he doesn't send them through like he did before, I tried hard hunting them down. I have the fractal plan but not the stepped diffuser so appreciate it you sending them through.

 

[Sonnie Parker]

Apologise, yes on your initial post has a pretty detailed layout of the build thanks.

I don't know much about the Martin Logan's wasn't aware they radiate backwards, now that I know it makes sense. Very interesting about you preferring the absorption perhaps your room is very small? Do you know the average time gap from the speaker to the diffuser then back to the listening position?

No problem at all.... and check out this thread with impulse and ETC measurements between absorption and diffusion... posts 32-33 ... https://www.avnirvana.com/threads/m...speaker-measurements-and-room-influence.8391/

My room is 19.5ft wide x 23.5ft deep and about 8.5ft high.

I've read in various places that absorption will generally give tighter and more focused imaging, but perhaps diffusion gives you a larger soundstage. I don't think diffusion really helps in my setup because the huge size of the 15A's produce an enormous soundstage even with absorption, but it also improves the imaging.

 

[Trdat]

No problem at all.... and check out this thread with impulse and ETC measurements between absorption and diffusion... posts 32-33 ... https://www.avnirvana.com/threads/m...speaker-measurements-and-room-influence.8391/

My room is 19.5ft wide x 23.5ft deep and about 8.5ft high.

I've read in various places that absorption will generally give tighter and more focused imaging, but perhaps diffusion gives you a larger soundstage. I don't think diffusion really helps in my setup because the huge size of the 15A's produce an enormous soundstage even with absorption, but it also improves the imaging.

You could place diffusion in such a way that secondary reflections get to it and get back to listening position. My next goal is to learn how to do this, it still should work in a small room.

One quick question, would particle board with the typical laminate cover(kitchen bench top material) work for the stepped diffusor? I know solid wood is best but the ease to cut kitchen chipwood or MDF at a factory would help a lot with my build and the overall look. I am presuming the laminated layer would be reflective enough. Does anyone have any idea if it's a wrong move or should work fine?

 

[Sonnie Parker]

I don't think the material would matter that much as long as it is reflective.

 

[VinceHoffman]

MDF would be fine @Trdat . Even particle/furniture board should be OK provided that the exposed cut faces of the lumber weren't too rough or full of air cavities.