Ideal design for a new music room


I'm designing a new house which will include a room dedicated to enjoying stereo music reproduction. In my experience, room acoustics have a huge effect on the sound in any particular room.

I'm interested in ideal dimensions, structural materials and finishes. Any experiences and stories anyone?

The music I mostly enjoy is classical, including organ, choral, chamber, solo instruments and orchestral. 
128x128encore
Robert Harley's current TAS article is a wonderful report about his design and construction of a DIY stereo reproduction room. Thanks very much for sharing so much practical detail.

This discussion thread has been very helpful for anyone with the luxury of being in a position to design for the construction of a new room. Thanks to all.

One subject I still wonder about: ventilation. What is the best way to keep the air fresh and comfortable through four seasons and not compromise the acoustics?
For ventilation I had ASC spec out a mini split which is a solution that will work just about anywhere, however I can still hear the unit when it’s on even two rooms away and through my sound isolated room. It’s probably unavoidable that low fan rumble will carry through any ducting into your room and the only fool proof solution is to turn the system off when you are listening - which will also remove any impact it has on the electricals as well

The ducting is all built into the acoustic soffit in my room, that way you get HVAC support without compromising the acoustic integrity of the room
Interesting. 

Can you give more details about the design of:
  • a "mini split"; and
  • an "acoustic soffit"

Thanks
@encore,

Here is a straightforward and perhaps unorthodox way of how I built my room. I built a combination home theatre stereo listening room. I built my room based off years of practical listening experiences, research on the Internet, and having experience of program oversight of building secure compartment facilities for the government. None of this compares to listening to music in various and different rooms and settings. Those listening experiences alone led me to have my own impressions of what I wanted. Number one, I can’t stand carpet in a dedicated stereo listening room, or home theater for that matter. I would rather spot treat reflection zones and use diffusion after I have made measurements. I have added carpet in front of speakers to be fair, but they serve a purpose. I prefer a natural decay of the reverberation time (RT), a measure of the amount of time it takes a specific or series of sound to reach a predetermined distance, otherwise known as RT60. It is the decay of the sound that is measured....with too much damping, carpet on the floor, padding along the entire walls, the natural sound of the music can become light and dry. You also don’t want too much, then you have echoes. So, I built a room using the knowledge that I have and what I know from experiences. This is a dedicated room,  not a studio, although some say it’s a studio because of what I did. Some rooms are full of carpet and sound good, but it’s a different good...for me, my benchmark is natural tone, and I lean towards that for my musical listening efforts. For others, perhaps not so much.

Basement room, concrete floor, 3 walls concrete
1. Room size: 33 feet long  x 19 wide x 8 high. Okay, not golden ratio, but a longer room will offset some low bass anomaly’s.

2. 7inches high density of spray foam under joists.

3. Roxul 16” Safe and sound under spray foam, and all walls (note: concrete walls had air barrier membrane that we left in place and put the Roxul on top of)

4. Resilient channel on ceiling and walls

5. Quiet rock 530 on ceiling and all walls. Another quiet rock layer 510 on ceilings.

6. Double back wall with 4 layers of quiet rock 510, 2inch gap between wall assemblies.

7. Bamboo floor over concrete.

8. Natural stone wall behind speakers (adds natural diffusion to the soundstage)

9. 2 sets of Stone wall pillars along the left and right walls ala home theater style, but again, purpose built for diffusion, and not looks,  but, it does look good.

10. Ceiling painted a low emmittance black, low light reflectivity value (3)

11. Walls same low value orange red brown,

12. 5 20 amp dedicated circuits (1 for amps, 2 for subs, 1 for sources, 1 AV rack)

13. Led color changing lights (with app)  in ceiling around custom built crown molding.

14. 13 foot wide acoustic transparent screen with speakers behind. In wall speakers built into quiet rock wall assemblies 7.1 channel.  

15. Various mix of diffusion and bass absorbers from Vicoustic and GIK.

Sound, wow, as you described what you wanted, a massive and immersive soundstage, that is what you get. Images float in space, and the reverberations of music are relaxing and a pleasure to listen to. A combined two channel and home theater room is really the best of both worlds. It’s the culmination of all of your years investment in music and stereo gear that really get a chance to shine here.

I was fortunate to move into a new build house and had the ability to build out the basement the way I wanted. So, I told the builder to leave the basement as is, with only the bar, game room, bathroom, and a bedroom being built. This gave me the chance to apply all of my knowledge gained over the years to build a room the way I wanted. Could have spent more or lesss, but I determined that for me, what I spent was just right, also, since it was a new build, I was able to do the wiring infrastructure at the same time. The listening room contractor was really good...when he ran power to a home theater riser cut through the concrete, I knew he was good. Now he is building a home theater for some very well known east coast football player.

If you search my handle in the analog section, you will find my report of a MC cartridge, but, I describe how the sound explodes and emits from nowhere and in a uncanny way makes you feel as one with the music. I would like to think that my room has allowed me to appreciate music even more. The room should be considered a part of the stereo system...and tuned to your liking. Good luck. I hope this short write up helps you a little.