Once again, thanks for all the great advice. My house is now being framed and the job is being supervised by the man who built Billy Graham’s recording studio. First off, I did have to compromise to make this both a listening room and a living room. At the end, it will still be better than I deserve (I hope). Here are the specs:
Dimensions: 32.33 X 20 x 12.08 (the rear wall has a 5’ opening on the left that adds another 23’ to the length and the right wall has an 8’ opening in the center that adds another 18’ to the width). Should I open up the rear wall another foot wider?
Floor: Manufactured support beams 16” on center with no more than an 8’ span. 3/4” super dense (50 year) floor boards nailed and glued. Another 3/4" will be added for hard wood. If there is any give at all, we will screw the floor board to the joists prior to the hard wood installation. Will have large area rugs.
Left Wall: A total of 16’ of glass (six wood and aluminum clad, low e windows) and a stone fireplace in the middle. 2x6 construction, 16” center to center, with stucco on the outside. 5/8” drywall.
All Other Walls: No glass. Offset 2x4 construction on a 2x6 base with each “wall” (inner and outer) built 16” center to center. Insulated. Using 20 gauge hat channel parallel to the floor (debating whether to go 16” or 24” center to center – thoughts on this?) to which a double layer of sheetrock will be screwed. Sheetrock in the room will be 1/2” (vertical) glued and screwed to 5/8” (horizontal) which is joined to the hat channel. Sheetrock on the other side of the wall is 5/8”. Is it worth the money to go to a high STC rating for the 1/2” sheetrock facing the room?
Ceiling: Same as “All Other Walls” in construction. Will also have 3/4" of gypcrete poured over it (not on it directly). The border of the ceiling, all around, is trayed (2’1” drop – 90 degree angle to the wall for 2’, then at a 45 degree angle for another 18” to reach the final height of 12’1”).
Built-in: About 15’6” wide and 8’ tall. Jutting out to 30” deep in the center (48” wide) and then dropping back to 2’ deep for the base unit with shelves above at 1’ deep. Height drops to 7’ in two equal increments from the center unit. All wood with some glass in the middle (is there a less reflective option that lets infrared pass?). My amps will be in the end base units with a mesh in front (rather than a door) and, probably, a remote fan pulling air through 4” vents in the back.
Acoustics: No pressure zone. Standing waves in the 12-105 Hz region (adding an active takes it to 210 Hz). First order standing waves are within 3db at 87 Hz & 140 Hz (plus 227 Hz which should be outside of the region). They are within 6db at 56 Hz, 174 Hz and 197 Hz. These are really good results compared to the calculations done by changing increments on any of the dimensions up to two feet. Using conservative absorption coefficients, reverb times are 1.5 seconds at 125 Hz and between 0.4 and 0.6 seconds between 250 and 4000 Hz. Reflection levels and delay times compute well – though the final proof is in the pudding.
I was not able to slope the ceiling or walls though that would have improved the acoustics (this was one of the design tradeoffs).
Any additional ideas? Comments on my questions (24” vs 16” on the hatchannels and the rear wall opening width)? Electrical design to come – have not yet met with the electrician (will try to stay away from romex, use 10-12 ga wire, use separate grounds). Thanks in advance for your comments or questions.
Dimensions: 32.33 X 20 x 12.08 (the rear wall has a 5’ opening on the left that adds another 23’ to the length and the right wall has an 8’ opening in the center that adds another 18’ to the width). Should I open up the rear wall another foot wider?
Floor: Manufactured support beams 16” on center with no more than an 8’ span. 3/4” super dense (50 year) floor boards nailed and glued. Another 3/4" will be added for hard wood. If there is any give at all, we will screw the floor board to the joists prior to the hard wood installation. Will have large area rugs.
Left Wall: A total of 16’ of glass (six wood and aluminum clad, low e windows) and a stone fireplace in the middle. 2x6 construction, 16” center to center, with stucco on the outside. 5/8” drywall.
All Other Walls: No glass. Offset 2x4 construction on a 2x6 base with each “wall” (inner and outer) built 16” center to center. Insulated. Using 20 gauge hat channel parallel to the floor (debating whether to go 16” or 24” center to center – thoughts on this?) to which a double layer of sheetrock will be screwed. Sheetrock in the room will be 1/2” (vertical) glued and screwed to 5/8” (horizontal) which is joined to the hat channel. Sheetrock on the other side of the wall is 5/8”. Is it worth the money to go to a high STC rating for the 1/2” sheetrock facing the room?
Ceiling: Same as “All Other Walls” in construction. Will also have 3/4" of gypcrete poured over it (not on it directly). The border of the ceiling, all around, is trayed (2’1” drop – 90 degree angle to the wall for 2’, then at a 45 degree angle for another 18” to reach the final height of 12’1”).
Built-in: About 15’6” wide and 8’ tall. Jutting out to 30” deep in the center (48” wide) and then dropping back to 2’ deep for the base unit with shelves above at 1’ deep. Height drops to 7’ in two equal increments from the center unit. All wood with some glass in the middle (is there a less reflective option that lets infrared pass?). My amps will be in the end base units with a mesh in front (rather than a door) and, probably, a remote fan pulling air through 4” vents in the back.
Acoustics: No pressure zone. Standing waves in the 12-105 Hz region (adding an active takes it to 210 Hz). First order standing waves are within 3db at 87 Hz & 140 Hz (plus 227 Hz which should be outside of the region). They are within 6db at 56 Hz, 174 Hz and 197 Hz. These are really good results compared to the calculations done by changing increments on any of the dimensions up to two feet. Using conservative absorption coefficients, reverb times are 1.5 seconds at 125 Hz and between 0.4 and 0.6 seconds between 250 and 4000 Hz. Reflection levels and delay times compute well – though the final proof is in the pudding.
I was not able to slope the ceiling or walls though that would have improved the acoustics (this was one of the design tradeoffs).
Any additional ideas? Comments on my questions (24” vs 16” on the hatchannels and the rear wall opening width)? Electrical design to come – have not yet met with the electrician (will try to stay away from romex, use 10-12 ga wire, use separate grounds). Thanks in advance for your comments or questions.