Very nice, Dr. K! That seating position surely provides a nice little bump to the first few octaves. And your portable absorption panels look almost exactly like the ones I made for myself...right down to the triangular-ish feet! How did the gridfusors work out for you?
Hi. Thanks! The diffusors improved the soundstage and helped reduce the very bad slap echo in the room along with the absorbers. I now have more diffusors covering the length of both sides of the walls near the ceiling.
I recently hung a panel bass absorber on the entrance door behind my listening chair (technically the bass absorbers are effective into the upper frequencies). This along with the panel absorber that stands at the front wall between the wall of diffusors deepened the soundstage, improved image focus, surprisingly increased bass clarity and extension, and helped to reduce a bass mode around 50-80 Hz. I now have no major bass modes that excite the room. Bass response is satisfyingly even, although not perfect.
I got rid of the absorbers for the 2nd reflection points on the side walls, as I found them dampening the sound too much and killing some of the liveliness my Raidho D2s are known for. Every speaker needs adjustment in the acoustic treatment because they all interact differently in the room.
Btw, I also use the panel absorber flat on the floor in front of the speakers to absorb the floor bounce. I was surprised to find the improvement in the overall clarity of the sound from lower midrange on down.
With my current setup, I get a wall of sound from floor to ceiling, beyond the sides of the speakers, and extending well beyond the front wall. There's excellent image focus within the soundstage. Of course, all this is dependent on the quality of recording. It took me 3 years of experimenting and educating myself on room acoustics to get to this point.
I consider acoustic room treatment the most important component of your audio system. Without it, your $10k+ speakers and expensive electronics are a waste of money. It's like buying a Fararri and only having a small parking lot to drive it in. And proper room treatment can make your $1k speaker sound like a $6k speaker.
The $3k I invested in room treatment is the best money I've ever spent in audio. Sometimes I'm befuddled by audiophiles who invests $5k+ on speaker wire or a power cord but none on room treatment.