Treatment behind dipoles

[crwilli]

Up until last weekend, i was living by the idea that my Betas should have a flat untreated wall behind the upper panels since they are dipoles. Even stating in a recent thread.

Then i read in another venue that some have successfully used QRD panels behind them. I had already started thinking that depth of staging front to back was lacking in my system.

From my GIK kit purchased earlier this year, i have two 'Monsters' on stands that have behind my listening position. However, my Monsters have the 'scatter plate' option and, jumping to the chase, I put them directly behind my upper panels and am now swimming in depth. Further, my lower region has taken another step towards greatness.

Now I am on the hunt for QRD panels as I am guessing the effect I am hearing is mainly from the scattering. Does this make any sense?

[jimtranr]

It makes sense to me. When I had a dedicated room now devoted to other uses, I initially had forward-radiating Symdex Epsilons out about five feet from the front wall, with Tube Traps set in the front corners and center. In that setup, everything sounded best with the traps oriented with their wholly absorptive sides facing outward.

When I replaced the Symdexes with Maggie 1.6QR's, I found that orienting the traps with their reflective membranes facing outward--they still also absorb in that configuration--rendered the best sonic presentation. Though the designs are different, I suspect that the scatter-plated Monsters would give similar results. And that QRD's in place of them back there would be the logical next step.

[GaryProtein]

Diffusion of sorts behind dipoles is fine. I think absorption behind a dipole makes it more dead like a cone. It depends on how you like it.

The wall behind my speakers is a rock wall (real, large rocks, not thin flat veneer rocks) that act as hard irregular diffusers except the area behind the power amps and crossover where I boarded up the fireplace, which is 1.5 inches thick of flat oak. There was a noticeable difference (I don't want to say improvement because there is personal preference here) when I boarded up the fireplace, which has not been used in the last 20 plus years. Who needs the smell and soot anyway.

[Glenn Kuras]

Now I am on the hunt for QRD panels as I am guessing the effect I am hearing is mainly from the scattering. Does this make any sense?

In a nut shell yes. What is nice though is you are getting some of the benefits of the low end control from the panel which is always welcome. For more diffusion I would look at the Q7d if you want to take it to the next level.

[crwilli]

Originally Posted by Glenn Kuras

In a nut shell yes. What is nice though is you are getting some of the benefits of the low end control from the panel which is always welcome. For more diffusion I would look at the Q7d if you want to take it to the next level.

Thanks Glenn. Yes, i was truly surprised both bu the wider and deeper sound staging but also by the increase i. Bass control. It is still deep but more defined.

Wont I lose that bas definition if I replace the monster/scatter with the Q7d?

[GIK Acoustics]

You may, yes. Basically the Monster is helping in the low end with SBIR (Speaker Boundary Interference Response SBIR GIK Acoustics), while the Scatter Plate is helping in the upper frequency by spreading out the image from the rear of the speakers. Both problems that it is helping are due to the speakers being too close to the wall. The diffusors spread out the sound that come from the rear of speakers to create a more cohesive "image" instead of sounding like distinct reflections (as if there were some quieter speakers further forward that were phasing with yours). Even if your speakers are far from the front wall, diffusion can still help further spread that image. Note that the Monsters are also helpful in just absorbing bass as well, but the effect on SBIR is probably gave them a pronounced effect when moving them. Depending on your room size/shape you could do diffusors to the sides of the Monsters up there.

[crwilli]

Alex, Thank you for the continuing education. Craig