Audio Cabinet Cooling

[Pookie007]

I am installing cooling fans for my audio cabinet this weekend and welcome any suggestions on my planned installation.

My audio equipment is housed in built-in cabinets. Currently there is no ventilation so I leave the door open. There is also a shelf 1/2 way up. The plan is to install 4 supply fans in one side and two exhaust fans on the other. I am also adding two vent holes at the top, and a few opening in the shelf. I am using six 3.5" computer fans that I am powering with transformer plug with a 4 pin connector. All the fans will be daisy chained. I intend to use the switched output so the fans come on when the equipment is turned on. The max current for the 6 fans is significantly lower than the current available at the switched outlet. Total cost for this set up is approximately $80.

Any thoughts?

[joecarrow]

If you get an enclosed column of warm things with a hole at the bottom and a hole at the top, it tends to create a chimney effect, aiding cooling by natural convection. When you think about the path the air will take, try not to fight this tendency. Move the hot air up, and don't expect it to make any turns or blow into any spaces that it doesn't have to.

Also, it seems like a good idea to put the hottest running components on the top so that they don't pre-heat the air for everything else.

Side note- I recently got an infrared thermometer, and it's been a lot of fun around the house! It let me know that my fridge was running warmer than is safe, and it was a really big help in measuring water and ambient temperatures while making pizza crust from scratch. If you love measuring things like I do and you don't already have one, it would be a fun thing to get to do some spot checks to verify and manage the cooling.

[Pookie007]

I knew the heat would rise, that is why I am putting two holes in the top of the cabinet. I am supplying air from 4 fans. Then I only have 2 exhaust fans. This will make the cabinet positive compared to the space above the cabinets and the air should be forced up and out of the cabinet. I don't think I can get enough convention purely from exhaust holes at the top.

[Gir]

$80 seems expensive. What part is so expensive? Also, I would probably go with only 1 or 2 120mm fans. This one can put out 110 CFM at only 39.5 dB, but if you lower the voltage you can significantly lower the noise. I would be almost positive you need but one or two of these, which is nice at $16.

[Amphiprion]

I would go with the Scythe S-FLEX series 120mm fans. Probably the 'E' series at Newegg (49cfm @ 20dBa). They also make a higher CFM but slightly louder model and a lower CFM but completely inaudible (8dBa?!?!). These have been reviewed very positively at Silent PC Review. Scythe is an excellent PC case fan / CPU heatsink& fan manufacturer, very well known on enthusiast forums.

They are pricey at $15 each, but you could put six on one of these for power:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=120-050

[JoshK]

I'd probably put a small trimmer pot in series with the fans so you can adjust the voltage if you wish to slow down or speed up the fans as wanted. You can usually use cheaper fans and undervolt them to get lower noise but I'd probably opt for nice ball bearing fans anyway so they stay nice and quiet.

This is a cool idea. (notice the pun?).

[engr_dave]

Careful Josh. A "small trimmer pot" will not likely have the power rating necessary to pad down a 5-7W fan (like the one Gir linked to). A 10W pot would probably be a prudent choice. These are not small...

[mmoeller]

Also, it seems like a good idea to put the hottest running components on the top so that they don't pre-heat the air for everything else.

I'm not sure that is correct. Components that run hot need more cooling. They should be on the bottom to receive the coolest air available. Components that natively run cooler can most likely deal with a little warm air. IMHO

[Gir]

No, putting the hot components on top is the correct choice. I've worked in some massive data centers and that's how they put them. It's not a matter of getting cool air in, as it is getting the hot air out. Then again this is for servers and networking equipment which pulls air in from the front or sides, so perhaps the method to cooling components that don't pull air in is different. Either way, I probably wouldn't worry about it too much, as most people don't have any fans running on them and it's fine being exposed to the air around it with small currents.

[wkhanna]

No, putting the hot components on top is the correct choice.

That is why I have always wondered why you don't see the amps on the top sections of audio racks. I was presuming that people want easy access controls, and therefore put items like pre-pros and pre-amps and CDp's and DVDp's toward the upper locations.

Maybe SS amps, in general, have made the heat much less of an issue compared the class A valve units we dealt with from my youth?

[joecarrow]

Some amps and racks also do a good job of bringing the air in and blowing it out in a more or less horizontal direction. I think that's why it's not a problem when people do that for the convenience of reaching controls.

[Gir]

You also have to realize that this type of equipment doesn't put out all that much heat. Sure it seems hot, but did you know that the processor puts out more heat per cubic meter than your ironer? I'm used to dealing with about 20-40 of these in an 8' space. Putting a few amps and other equipment like that close together isn't going to cause much of an issue and requires little airflow.

[Pookie007]

The higher cost was from going to higher quality fans. I could have done it for less money but didn't want to be disappointed. Since the fans are in the adjacent cabinet, any noise would be amplified. I am starting drilling holes on Wednesday. I will keep you posted. I might even throw up a photo or two.

[mmoeller]

No, putting the hot components on top is the correct choice. I've worked in some massive data centers and that's how they put them. It's not a matter of getting cool air in, as it is getting the hot air out. Then again this is for servers and networking equipment which pulls air in from the front or sides, so perhaps the method to cooling components that don't pull air in is different. Either way, I probably wouldn't worry about it too much, as most people don't have any fans running on them and it's fine being exposed to the air around it with small currents.

I was curious about this so I did some reading. If you check out the Thermal Management white paper on the Middle Atlantic website.

http://www.middleatlantic.com/techs.htm

All the info you'll ever need. The jist of the amplifier placement quandry panned out like this.

1. If the rack is not using fans (convection cooling), amps placed on the bottom produce a more natural air flow. (chimney)

2. Racks with hot ambient temperature with active cooling (fans), amps should be place on top.

There is a ton of good information in that paper. I'd definatley read before cutting any holes Pook.

[Gir]

I was curious about this so I did some reading. If you check out the Thermal Management white paper on the Middle Atlantic website.

http://www.middleatlantic.com/techs.htm

All the info you'll ever need. The jist of the amplifier placement quandry panned out like this.

1. If the rack is not using fans (convection cooling), amps placed on the bottom produce a more natural air flow. (chimney)

2. Racks with hot ambient temperature with active cooling (fans), amps should be place on top.

There is a ton of good information in that paper. I'd definatley read before cutting any holes Pook.

Ahhh, that makes a lot sense. Thanks for the info!

[Pookie007]

I got the fans installed and it works beautifully. All the holes go into adjacent cabinets, so unless you are on your hands and knees with a flash light you can't see them. I also got some low noise fans for coolerguys.com. With the doors shut you can barley hear them if everything is perfectly quiet and you really try. I think my house AC actually make a little more noise.

I read all the stuff but it wouldn't help me. I have 4 amps in the cabinet that I stack two on the bottom and two on the shelf. The cabinet is two components wide, so I have the amps on the right side and the equipment on the left. The center speaker obstructs your ability to open the right door. That is why the amps are on that side.

[pereze]

Sorry for the Dup post. It was giving me an error.

[pereze]

Pics?

[Pookie007]

Hopefully I will have some next weekend. My wife took the digital camera to visit her sister. It's ugly, but functional.