Hi lak-here are my answers.
1. & 2. My floor is concrete with plush carpeting.
3. The Mapleshade platforms are laying flat on the carpet (I previously had 1" thick granite tiles-worse than directly on carpeting).
4. The Signature IIIs are spikes on top of the platforms.
Hi slaw - My room is 13' wide and 30' deep to an open foyer which measures 8' X 55'. There is antique wood and glass furniture in the foyer and adjacent dining room, mostly stuffed wood chairs and plush couches in the listening room. The speakers are 6' from the front wall and 3' from the full right wall and half height left wall which is open to the dining room. The ceiling is sloped from 8' at the front wall (speaker side) to 10' in the foyer. This room has excellent acoustics.
My main audio room is 25' X 23' X 10-12'6" cathedral with a rear 6' X 8' audio equipment closet area. Unfortunately, when I built the room, which has a 6" thick 3/4" rebar reinforced concrete floor, plush carpeting, 10" and 12" exterior walls with staggered 2X6 studs, dual 5/8" X drywall panelling, LPs & 78s line most of the four walls and there are three sets of dual glazed, wood casement windows.
I forgot to build the ceiling correctly. I have a terrible slap echo from the single 5/8" X drywall ceiling with open 6' attic. So, I recently purchase Synergistic Research HFT room treatment Level 1 and 2 and dual speaker kit treatment on a friend's recommendation (oregonpapa on Audiogon forums). The result is that the slap echo is virtually eliminated when music is playing (no bright or hard upper mid frequencies). Hand claps are nonreverberant when music is playing. In the past, I tried all sorts of acoustic treatment but the absorbers tended to dull the dynamics and collapse the soundstage while diffusers only made the sound harder and brighter. The single SR HFT on the ceiling is a wonder. It really makes a huge difference and I removed all acoustic wall treatments after installing the SR system. It was also less expensive than the panelling I had installed.
