Air conditioning a home theater.

I have converted my den into a dedicated home theater and listening room. It is posted on Audiogon's Member Systems under Home Theater, Marc's Media Room Madness. The room is great but, since the warmer weather started, we discovered that our home's central air conditioning system is inadequate for cooling that room. Perhaps enclosing the previously open entrance to the room and the addition of carpeting and black out curtains is retaining heat more than before. There are various solutions. The two we are considering are to turn our central system into a zone system or install a "mini split" system. I would appreciate hearing from anyone who can weigh in on which system is more efficient and, most importantly, which one is quieter. Thanks.
Mr. Slim has got to be quieter than central air (I guess this would be a split-mini or a ductless system). They are quite popular in Japan, from what I understand.

I can't comment on the efficiency of energy consumption though.
There are other alternatives to consider that are less expensive too. Without knowing your house layout (1 story or 2, location of room, etc) I'd venture to say the carpet and drapes present NO problem at all. The drapes probably BLOCK heatflow through the window, if it is on a southerly-exposed wall. If so, even planting a diciduous tree of the correct size by the window will help with the cooling.
Also, you could divert MORE of the AC TO your AV room and let your other(s) room warm up more, if your lifestyle would allow that. That can be accomplished by having an AC tech install dampers in the ductwork, allowing you to direct the flow to the rooms you choose.
Hope that helps or gives you some ideas.
Good Listening & L@@king!
Marc, Zone the house, use acoustic rigid duct for this room. Your HVAC contractor will know. Up the tonnage. This will cost a few dollars, but depending on the age of existing unit, utility bill will drop. You will also need a door to this room. Having common supply or return defeats the purpose. Z.
whats wrong with a simple window air conditioner?
Bigjoe, Noise is what's wrong, both audible and electrical.
Marc, a couple of questions:

1.) Was the room adequately cool and comfortable in past summers before the recent conversion? I'm guessing 'yes', because . . . . . . .

2.) There appears to be a fairly large supply register on the wall above your TV. Is there a return air register somewhere else in the room? I'm guessing 'no' because . . . . . . .

3.) The supply air probably originally found its way back to the A/C fan through the (now closed up) opening, via a return air grill somewhere else in the house (a central location, like the hallway.) Am I correct?

If I am correct, you need to 'uncork' the room in some way, because the supply register is now trying to 'pressurize' the room, and it cant, so little or nothing comes out of it. There are a number of ways to fix this, and I'd be happy to list them, but here's one that (after looking at your setup) will both keep your room cooler AND keep any component heat out of the room (and keep the components cool too!):

If the closet behind your equipment has another wall (or door) which adjoins a space that has unobstructed access to the main return air register (like the hallway), then all you need to do is install a "transfer grill" in that wall, preferably up high, or above the closet door, so hot air won't collect in the closet. (A transfer grill is just a hole in the wall with a grill on each side to dress up the hole.)

If that is not possible (no adjoining wall in the closet) but there's an attic space above the closet, then install a grill in the ceiling of the closet and run a duct from that grill to the main return duct of your system. It will work just as well, but will cost a little more.

(Make sure any return air grill and duct have at least 1.5x the area of the supply grill and duct.)

Anyway you should be able to do some version of this, and it should solve the problem. With the additional feature that your components will be cooled and won't add any extra heat to to room.

The slim units are notoriously expensive to repair and the indoor unit should not be more than 25 feet from the outdoor unit so as not to burn out the compressor. They are more efficient than an in-window unit but start out at 12,000 btu and above - so they require more power overall.

My suggestion to the cheapest solution would be to ventilate the closet in the back of your rack with a ceiling exhaust fan and run the exhaust air via a round duct outdoors. The heat build up from your equipment rack is contributing to the load that your present a/c system cannot handle. By exhausting the air from the closet, you reduce the air temp back to the a/c unit since the make up air is taken from the conditioned space inside the house.

Broan ( makes a "LoSone" fan that is dead quiet. I would use a 200 to 300 cfm fan in the closet ceiling with an 8-inch flex round to a wall jack outside the house. If you can spend a little more, wire the fan with a dedicated circuit to minimize electrical noise.

This is the way telephone/network server closets in buildings are ventilated; it seems you have a similar heat load.
Marc, Your pictures were not up for my first response. Nice room, nice system! Nsgarch is very close to making this a freebee. If it was all good as a den, and you do not have a return in this room, you need one. A transfer, say, above the door, like a transom, will work and keep things pretty. Same size(cfm)as supply is fine.The downside to this is it will also transfer sound and light! I see you have Krell and a sat. reciever. You are making (and keeping) a LOT more heat in this room now. I suggest an exhaust fan in the closet. Put it in the attic and duct it to a grill in the closet lid. This is quieter than just popping it in the ceiling, like in your bathroom. Go to a high end supply house, you will find something very quiet that will pull bigtime. Make sure you have an inch or so gap at the bottom of closet door. Done deal. Z.
Thanks to all for the great information and recommendations. The air conditioning system for that side of the house does not pump much air into the theater. My HVAC contractor has proposed turning the existing vent into a return and running a new inflow duct through a larger vent in the ceiling. But he thinks that the room would still be warm because it faces the sun while the rest of the rooms supported by that air conditioning system are all in shade. So cooling the warmer room, the theater, would mean making the other rooms frigid because they are naturally cooler. He recommends the mini-split as the most efficient and the most quiet. And he would close off the duct to the theater at the source which would make the existing system operate with a little more efficiency. But I have no way of testing a mini split system or seeing it demonstrated before taking my chances and spending a lot of money. Either way, a fan in the equipment closet sounds like a good idea.
I had a problem similar to yours in my last house. I converted an upstairs bedroom into a HT room. The bedroom had previously been adequately cooled by the upstairs central AC system, but between closing up the room, adding all of the heat-generating HT gear, and keeping the room filled with warm bodies for hours at a time made it sauna-like, especially in the summer.

I had one HVAC contractor suggest a mini-split system, another suggested adding a return and upping the tonnage on my upstairs AC unit. Both options were extremely pricy, and both options would increase the noise level in the room substantially.

I ended up putting in long speaker cables and moving every piece of gear but the display into a closet in the room. I lined the closet with Sonex, and put a couple of quiet computer muffin fans in the closet to stir up the air. I then vented the closet with 4" ducting that ran to a Nutone in-line fan up in the attic. An in-line fan is installed as part of the duct, not in the room's ceiling, so you can put the fan far enough away that there is no fan noise in the room, only the slight sound of the air intake at the duct.

This completely solved my problem. Hot air from the equipment was removed from the room before it could ever affect the room occupants, pressure in the room was reduced to the point that the original house AC was adequate again, the noise level in the room was not appeciably increased, and total dollar outlay (including the long cables) was about 1/10th of the cost of AC work.

Try it before you spend big bucks on air conditioning.