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Who has solved the HVAC air noise problem?

I am in the redesign stage of a totally dedicated listening room which will inlcude tube amp, pre-amp and cd player. The reconstruction will include a flat ceiling and tons of sound isolation and insulation. The central air system for the house with constant air flow produces way too much background noise and hum through the vents. I want to add a separate dedicated a/c system for just this room (25Lx15W x 9.5H). I am looking for the advice of those who have managed to baffle internally in the ducts sufficiently to eliminate the air flow noise and machine hum, while still having an effective a/c system. I want an invisable a/c system with five overhead vents. Duct size should not be a problem as the walls will be at least 12" thick at one end. I presume that fiberglass or lined/insulated sheet metal with all surfaces covered are the way to go. BUT, I really don't know. What I know is that I want to be able to never hear the environment, only the music.

All thoughts welcome including my obvious need for more therapy.

Bill E.
lakefrontroad
mzn50
180 posts
 
The ducts are not the problem I found when building my room ( see http://www.angelfire.com/mn2/mzn50/ and click on the CAD) you will see that I have installed insullated ends, like mufflers, they do a great job and my room is dead silent.

Good luck
Matt
lakefrontroad OP
302 posts
 
I have returned to re-read this thread after so much time has elapsed. The comments have been right on point. Thank you. It is the return system which has caused the problem. I have a dedicated 2.5 ton hvac system with hydroair heat directly below the green marble shelf. The returns which draw air across the amps produce 50db at 25hz.

The initial attempt to baffle them in the return boxes, each of which has it's own 12" round duct to the blower unit reduced the volume but did not eliminate it.

I have been advised to have the ducts interrupted by making a horizontal turn, then a downward turn, then a horizontal turn, then an upward turn and tie on back to the system. Each leg to be treated similarly and each duct lined with hospital grade accoustical liner and wrapped with fiberglass insulation.

Your thoughts please?

Bill E
gardengirl
16 posts
 
Problem Solved!...
build an earthship. We have NO need for heating or cooling year round - not even a crackling fire ;-)
http://www.ranchocalypso.com/

then again solar electric power and tube amps can be a problem.
lakefrontroad OP
302 posts
 
???

Gardengirl must have taken lessons from my wife. I don't understand a thing she says either.

Bill E.
lakefrontroad OP
302 posts
 
The proposed fix by the acoustical consultant is re-routing the duct to make several turns and line the duct with acoustical liner. The contractor prefers to install baffle boxes since shop time would be higher and field time would be almost none.

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