Need help with stereo cabinet design.

Just thread refrigerant tubing in the isolation draining sloted maple or I might add Myrtle shelves. Put the compressor far away in a different structure if you can. The compressor draws a bazillion amps so keep it well clear of the audio component's dedicated lines and have it on a 240 volt outlet of it's own. You will need a very quiet tuned port to evacuate the air evenly . a simple bulbous portable Oreck type house hold vacuum cleaner should be kept in the basement rember to get a very long special extension tube with splitters and nozzles for each compartment.

I would build a small closet between and behind the speakers. Use curved walls which are double-insulated. Insulate the ceiling and floor. Sliding glass door (heavy and double-insulated) on the front with heavy curtains attached to the front. Put 5 dedicated outlets inside, along with an adjustable fan and a vent hole to outside. Create a small hole on either bottom side to run your speaker cables, and pack them full of some thick cushioning material. Have an isolated ground for your dedicated outlets with an audio-grade grounding rod (one for analog, one for digital). Look into audio grade wiring (8 gauge). Consider adding an ExactPower PowerCore and Conditioner. Put a HRS rack inside the closet. Then there will be nothing further to do.

I'm sorry. There is one more consideration for isolating everything from the floor. The floor inside the closet should be built on their own floor joists that are separate from the room and the closet wall. An elastic skin can be used between the joist and the flooring.

Now you have ground, air, electrical, and component isolation.

Consider a thermal alarm inside, in case of fan failure. There may even be a way to set the fan on a variable speed thermostat.

Jgiacalo is correct, get the blower as far away as possible.

I built a closet for my equipment. I ran 2 blowers, one on each side wall. One blower brings conditioned air in from the hallway and the other to take the air out and to the attic. I ran 4' insolated flex duct from each blower and then reduced down to 2" PVC with a 2"T every 6 inches. The 6" spacing allows me to put the shelves where ever I want and still get air onto the shelf. Then I used armaflex with different diameter holes to control the air volume from each 2" hole of the pvc supply. The only place in the closet the air does not go is where my TT is, those holes are blocked off.

If you are going to use a blower to move air only in or out, you must make the unit loose so it can get the air from the room or send it into the room. If the structure is too tight you will not get any air. The air must have some place to go.

I used Russound ACT1 12 volt trigger to turn them on and off with my ARC REF3.

if you live in a cold climate, do not duct the run into the attic. Either run out through the attic and out the roof, or out the side of the house. You never want just plain warm air dumping into your attic.