Reducing HVAC Noise in Theater Rooms
Audiophiles jump through proverbial hoops upgrading their systems, believing in cable pseudo science magic or the latest tweak to reach sonic ecstasy. Yet they rarely consider the room it plays in, or the acoustics of their listening space. Getting a good acoustical room balance is key. A good system in a mediocre room is no better, and usually worse, than a mediocre system in a good room, so to speak. After the acoustics in the room is sorted out, the next logical step is to minimize external noise influences which have deleterious masking effect on the audio reproduction much like light pollution does with display devices.
Step 1: Identifying the Problem
HVAC noise is usually the #1 problem in home theater rooms. Minimizing the source of the noise is one of many steps in the pursuit of a state of the art theater room. While building the theater room in the Audioholics Showcase Home, I was well aware of the importance of noise control and isolation - particularly from HVAC. Unfortunately I was at the liberty of my builder as to what countermeasures I could undertake. Sadly I lost the battle of having them install my air handler in the same room as my theater, but at least I got them to put it into a closet which I could later isolate once I closed on the home.
On a positive note, my air handler was placed on a shelf which helped to decouple it from the flooring. The builder used cheesy hollow double bi-fold doors with nearly a 1 gap at the top and bottom as the entry point to the air handler. I knew these had to go from day one but wanted to formulate a game plan before yanking them out of the room.
I began doing some listening tests with the HVAC system on and off at various SPL levels. I found that at my primary listening position, nearly 20ft away, the air handler was creating enough noise to introduce a masking effect even when I was listening at levels in excess of 90dB. Low level details were virtually non existent from my music, and I found myself becoming quite irritable as a result each time the HVAC system would turn on while I was in a listening session. I quickly learned to live in a hot room for the pursuit of better audio. This could not last. I needed to be comfortable. Pursuing sonic nirvana while wiping off a head full of sweat did NOT an audiophile experience make.
Step 2: Devising the Solution
My goal was to turn the air handler closet into a quiet room - allowing minimal sound transmission from the air handler out of the closet and into my theater room.
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