Absorbtion or some diffusion

[Davioj]

I have some reQuest speakers that I cannot move any farther from the front wall they are 2.5 feet out, I have absorbtion panels behind as shown in the pics and base traps in the corners and was wondering about putting diffusion panels with the absorbtion panels if they would make a difference or are the speakers too close to the front wall and it would not work. I also thought about moving the absorbtion panels over and just adding another panel beside them as that is an option, also shown pics of the absorbtion on the side walls see what other peoples opinions on this are, right now it sounds pretty good, just looking to improve the sound and widen the soundstage if that is possible. You have to use what you are given to use so I'm just trying to improve if I can.

Dave

 

[JonFo]

Hi Dave,

My take is that, especially for surround setups, absorption is the way the way to go. So you are on the right track, but the setup could benefit from some tweaks.

First, the absorber the panels are aimed at should not have any reflective elements. Often, bass traps have a 'limp mass' sheet of vynil in them to lower their effective range, but they also act as a reflective surface at higher frequencies. And your Quests seem to be toed in, so much of the rear-wave is hitting those bass traps, and reflections could be coming back and causing comb-filtering.

Secondly, the bare wall between the bass traps and the absorber behind the speaker is a problem, and the absorber itself is too thin to effectively improve mid-bass dipole cancellation. Ideally, the absorber behind is wide enough to fully cover the area of the wall the panel is energizing; it should be 4" thick and offset from the wall by 3" to lower the effective absorption into the 250 ~ 300Hz range. As noted above, the construction should have zero limp-mass or other reflective elements.

Expanding the soundstage should result as a side effect of killing more of the rear-wave reflections. It should also widen the 'sweet spot'.

 

[Davioj]

So are you saying to not toe the speakers in so much and fill in the bare wall behind the speakers with thicker panels and check to see if the panels have any reflective elements

 

[JonFo]

Leave the toe-in as-is, but do take care of that bare wall by using a wider, thicker absorber, like a RealTraps Minitrap HF (the HF lacks any limp mass).

 

[Davioj]

Leave the toe-in as-is, but do take care of that bare wall by using a wider, thicker absorber, like a RealTraps Minitrap HF (the HF lacks any limp mass).

Ok I'm looking into a 3" panel, that will fill in where the 1' panel is that is only 2", these panels don't have any reflection in them they are only absorbers, was going to mount them 2" from the wall leaving a space behind them, I did move the toe in a little less from the way they were and it did seem to widen the soundstage a bit, going to experiment, don't have any meters to take readings with though. If I was technically able would like to go to an external crossover to run the woofers in my mains but I don't think I have the knowledge to do that but that's life you can't be good at everything, thanks for the advise JonFo much appreciated.

Dave

 

[Tmort]

I definitely think the original toe-in was a bit extreme so as you discovered already pointing them a bit more square will likely help. Note the “flashlight technique “ ML suggests for setting toe-in.
I also concur that I’d go with a thicker and wider panel behind them.
I’d suggest:

https://www.gikacoustics.com/product/b4-bass-trap-acoustic-panel/

That’s what I’m using (2x4 panels), behind my classic 9’s which are similar to your panel sizes and mine are about 34” from the front wall. These panels give you a 1” air gap behind the acoustic material as built in the frame. Their upgraded fabrics are worth the minimal extra $’s.

Good luck!

 

[Davioj]

My panels are 15" wide I think the classic are about 9" wide but I have been experimenting with the toe in and it does make a Difference with no0t so much toe in, I used the flashlight method to set them up the first way and that's what I come up with but you just have to keep experimenting with this. I wish I lived in the USA as GIK are located in the south, I will have to look into them shipping up here or get them shipped to my brother in laws in PA.

Thanks

Dave

 

[Tmort]

My panels are 15" wide I think the classic are about 9" wide but I have been experimenting with the toe in and it does make a Difference with no0t so much toe in, I used the flashlight method to set them up the first way and that's what I come up with but you just have to keep experimenting with this. I wish I lived in the USA as GIK are located in the south, I will have to look into them shipping up here or get them shipped to my brother in laws in PA.

Thanks

Dave

I was just going off visual so heck if yours are 15 inches wide then you’ve some serious rearward wave action going on, definitely a good thick absorption panel of substantial width is best!