Room treatment - Argent Room Lenses / Jon Risch Room Lenses

[HiFiFuchs]

A few weeks ago I built two Jon Risch clones of the former Argent Room Lenses.
The Room Lenses are made from high density thick walled PVC tubes, sitting in a base made of MDF and the tubes are open at both ends, The tubes are stuffed with buffy polyester batting at different specific heights to absorb typical 8 foot = 2,43 m ceiling resonance mode, effectively damping these unwanted frequencies.
The effect is based on the Helmholtz resonator princip and at the same time they course diffusion off the rounded tubes.

I have placed them behind my ML Aerius speakers. The result is definitely positively audible but I would be very pleased to hear from anyone of you out there if you have made experience with such room lenses room treatment.
For those of you who might not know what Argent Room Lenses are, I have uploaded a picture of the ones I made.

Where did you place the lenses to get the best sound stage improvement?
As you can see on the pictures I have a TV screen between the speakers, which does not allow me to place a third lens between the speakers.
Any help/suggestions are very welcome.
Thank you.

 

[HiFiFuchs]

No one out there that has experience with the room lenses?
I do know that the Argent lenses are not available anymore but I was hoping that some of you made the clones and would share your experience either with the originals or the clones.
Thank you.

 

[JonFo]

I don't recall seeing anyone discuss these specific types of resonators, the one thread that did reference this design is this one: Bass trap tubes - need help & ideas

Do you have a measured peak resonance at where your lenses are placed and is the tube length tuned to that?

As for the diffusion, it helps remove some of the comb-filtering, but some absorption would be even better, have you tried covering the fronts of the tubes with 2" (or thicker) absorptive materials?