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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

Showing 7 responses by lakefrontroad

lakefrontroad OP
302 posts
 
Roger,

You say that you have suggestions about the counseling?

Bill E.
lakefrontroad OP
302 posts
 
Dweller,

I've done very similar baffling in hvac systems in a prior home to reduce air noise. The staggered baffles were metal disks with the centers cut out which slowed down the air in line ahead of the vents by a few feet. It reduced the noise enough that I could tolerate being in the room, but I wasn't looking for zero noise and can't remember how quiet it was.

Your solution sounds more effective. As to the flaring, it makes sense to me. I can't imagine that the loss of back pressure to the vents would have any effect since I'm only trying to balance one rooms vents.

Is there an excellent solution for dust management?

Best wishes,

Bill E.
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
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.

Results to follow.
lakefrontroad OP
302 posts
 
I will never compromise or surrender. It's much more fun to have intricate interiors to metal boxes. We feel that the baffle boxes will solve the problem and eliminate the hum. It's really quiet, but annoying.

If I could deal with the heat and no air it would be different. The room is tight, and shortly will be sealed.
Therefore, it's necessary to have the a/c on to bring in intake air.
lakefrontroad OP
302 posts
 
Yes, I am.

The room hvac is designed to run a/c year round. and it needs to. Last week when the heat was on in other parts of the house and the system was off, the room was 80 degees. The heating system is below the room. Although there is insulation and three layers of buildup in the boiler room, it still heats the listening room.
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