The Perfect Listening Room

Is there such a thing?

Or is the perfect room a function of your speakers?

Whatever the case, I would like to build one for my Magneplanar Tympanis.

Thank you for your thoughts.
Based on my experience listening to the transformation of Audiogon member Slipknot1's room as he implemented recommendations from Rives Audio, it might be well worth using their consulting services on the front end of your planning process. Here are his comments about his experience:
2 Channel System Rives Redo
As an avid accoustic original music fan (see websites for the Kerrville Folk Festival, UncleCalvins coffee house in Dallas and Jefferson Freedom Cafe in Fort Worth), I have been in the perfect listening room. It's a thing called a house concert and they are put on by loyal fans. Usually its just the performing singer songwriter and anywhere from half a dozen to a hundred folks enjoying the music close up and personal. No mics no sound system just the real thing. I have been trying for years to get this sound in my living room using recorded music. This past Tuesday evening I was at a house concert in Dallas with T. R. Ritchie performing at the home of friends who are also involved in this music.
The guitar sound was amazing and TR's vocals were perfect. There was just over a dozen of us there and after enjoying a wonderful meal prepared by our host and hostess we enjoyed about two and a half hours of great music.
I've also had a great experience with Rives. The quality of the sound & working with them has been a pleasure.

Feel free to email me off-line for details if necessary.
The perfect one is an aneholic room where speakers are being made.

Other than that my favorite

#1 Radio City Music Hall;
#2 Tow Hall;
#3 Irridium Jazz Club;
#4 Birdland.

You may research the accoustic tweaks used in Radio City through the libraries if that is your goal.
How about Carnegie Hall?
Carnegie bests with solo live performers whilist Radio City bests in both cases whether its one or band or the orchestra.

An anecohic room is far from ideal for enjoying your speakers. Such rooms are oppressive and the sound of speakers is disappointing without reflections. This is especially true for rooms that are anechoic even at low frequencies. There's something about those deep wedges that's unnerving. I was shocked by my first exposure, but eventually grew accustomed to being in our room.