tomlinmgt
Lunatic Member
Got this idea from RevMen (thanks Josh!). Very simple, inexpensive, and most importantly effective diffusion panels. They could serve double duty as diffusion and absorption if you were to drill lots of holes in the tubes and get some absorptive material behind them (again, RevMen's idea) but I elected to try it first with just diffusion as I have first reflection absorption panels on the sidewalls and ceiling.
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I used 1",2",3", and 4" PVC. The 3" and 4" I cut in half with a jigsaw. There's nothing magical about these sizes and I imagine you could go to larger dia. pipe if you wanted but it may not be worth the expense. I would estimate cost at around $40 to do what you see here. They're 5' tall and the panel is 30" wide with four 1x2 straps across the back that the PVC screws into...like a stockade fence panel. There's no special pattern to the sequence of the pipes. I held the pieces upright in a bundle and then let them go so they just fell and scattered randomly on the floor. I started picking them up from left to
right and that's how I got my sequence. However, I did mirror image the two panels because I'm anal that way.
Here's what they look like in the room....
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Because of the hot water heater in the right corner I can't get the panel on the right as far outboard as the one on the left (so it's directly behind the speaker).
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Initially I had floor to ceiling absorption panels in the room....
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....which worked great for my cone/box speakers but the dipole design of my newly acquired Magnepan MMG's didn't seem to work well with this. After a little research I discovered the dipole Maggies like diffusion behind them...which makes perfect sense as they sound the same behind as they do in front (except for out of phase) and all that sound going to the front wall and getting diffused about the room is what gives them their marvelous sound stage and imaging. With absorption behind them they lost much of the transparency that impressed me when I was auditioning them. You could hear exactly where each speaker was located and there was very little imaging and not much of a sound stage. Taking the absorption down helped a lot but the speakers still weren't very transparent and I felt the sound wave reflecting directly back into the speaker was messing with fidelity. Once the diffusion panels went up there was an undeniable improvement in SQ. I was able to spread the Maggies another foot apart which widened the sound stage so there's clear extension outboard well beyond the speakers. Trying this without the panels caused the sound stage between the speakers to break up and lose strength of presence in the middle. Now the Maggies are much more transparent, have wall to wall and three dimensional sound stage, and refined fidelity that really lets the detail of the speakers come out. My friend that was over last night (who has a pretty nice rig of his own) repeatedly commented on how he was hearing notes he'd never heard before or heard them more as "blur" or notes. I've been impressed as hell with the Maggies since I got them....now I'm simply blown away and the diffusion panels are what took them to that next step.
Here the panels are in service behind my QLS-1's which have a rear firing EMIT tweeter and a dipole-ish mid-bass driver. As expected, they opened up the soundstage with improved presence behind the speakers.
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I used 1",2",3", and 4" PVC. The 3" and 4" I cut in half with a jigsaw. There's nothing magical about these sizes and I imagine you could go to larger dia. pipe if you wanted but it may not be worth the expense. I would estimate cost at around $40 to do what you see here. They're 5' tall and the panel is 30" wide with four 1x2 straps across the back that the PVC screws into...like a stockade fence panel. There's no special pattern to the sequence of the pipes. I held the pieces upright in a bundle and then let them go so they just fell and scattered randomly on the floor. I started picking them up from left to
right and that's how I got my sequence. However, I did mirror image the two panels because I'm anal that way.
Here's what they look like in the room....
Because of the hot water heater in the right corner I can't get the panel on the right as far outboard as the one on the left (so it's directly behind the speaker).
Initially I had floor to ceiling absorption panels in the room....
....which worked great for my cone/box speakers but the dipole design of my newly acquired Magnepan MMG's didn't seem to work well with this. After a little research I discovered the dipole Maggies like diffusion behind them...which makes perfect sense as they sound the same behind as they do in front (except for out of phase) and all that sound going to the front wall and getting diffused about the room is what gives them their marvelous sound stage and imaging. With absorption behind them they lost much of the transparency that impressed me when I was auditioning them. You could hear exactly where each speaker was located and there was very little imaging and not much of a sound stage. Taking the absorption down helped a lot but the speakers still weren't very transparent and I felt the sound wave reflecting directly back into the speaker was messing with fidelity. Once the diffusion panels went up there was an undeniable improvement in SQ. I was able to spread the Maggies another foot apart which widened the sound stage so there's clear extension outboard well beyond the speakers. Trying this without the panels caused the sound stage between the speakers to break up and lose strength of presence in the middle. Now the Maggies are much more transparent, have wall to wall and three dimensional sound stage, and refined fidelity that really lets the detail of the speakers come out. My friend that was over last night (who has a pretty nice rig of his own) repeatedly commented on how he was hearing notes he'd never heard before or heard them more as "blur" or notes. I've been impressed as hell with the Maggies since I got them....now I'm simply blown away and the diffusion panels are what took them to that next step.
Here the panels are in service behind my QLS-1's which have a rear firing EMIT tweeter and a dipole-ish mid-bass driver. As expected, they opened up the soundstage with improved presence behind the speakers.
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