I have been listening to my MG IIIa’s since 1988. Peter Gunn generously advised me to screw as much natural wood to the back of the particle board frames as possible to absorb vibration and he shared the schematic for his crossover. I installed 36’ of 2"x3" studs per speaker and built his crossover ($900 in parts). Major improvements.
Recently, Peter advised me to place a screen behind my listening position to enhance bass response. I constructed a frame to hold a 2’x4’ piece of plywood covered with 2" of Rockwool that is mounted horizontally 34" from the floor and another piece of 2’x4’ plywood covered in Rockwool that hangs over the listening area at a 30 degree angle. I had been using an 18" sub with a low pass of 35hz. The sub is no longer necessary, unless you want sub 25hz support. The over all sound is cleaner without the sub. The overhanging panel helps eliminate sound bouncing from the ceiling. It’s like having a folded horn located behind you.
My room is 35’x25’x14’ (tray ceiling). I installed a diffuser on the middle of the front wall and the sound stage bloomed. The Maggies are powered by a Devialet 220. The Devialet replaced a Pass Labs 250.5. The amp is connected to the speakers via sixteen 5’ 0 AWG copper cables.
I highly recommend you consult Peter Gunn and consider buying one of his modified 1.6 QR’s. Unfortunately, Peter does not modify the bigger models due to shipping constraints.
An Audiogon poster, b4icu, recommended the speaker cables. Shocking results as I added one cable at a time.
I have had many box speakers. They sound good, but they don’t have the magic.
Good luck.