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Heat Buildup and Your AV Components

by Bo Dragsdahl April 14, 2007
Heat Buildup in Components

Heat Buildup in Components

If you want to ensure that your expensive electronic components enjoy a long and full product life cycle, you must make sure to keep them operating at a comfortable, cool temperature. The number one factor that kills electronic components is overheating. Even short of an outright meltdown, excessive heat causes electronic components to function less reliably and reduces their overall life span.

Stay below 85 Degrees F

To achieve optimum performance and optimum equipment life, it is recommended that you keep your system operating at a standard temperature below 85 degrees F. Most studies show that every 10 degree increase over 85 degrees F leads to a whopping 40% reduction in your equipment’s life span.

Computer microprocessors are more sensitive to heat than traditional A/V equipment. All microprocessors have a maximum allowable temperature, beyond which they burn out. With the increasing use of microprocessors in A/V components, sound system owners nowadays have to contend with the same heat sensitivity problems that computer owners have for decades.

Where does the heat come from?

Ironically, the heat that threatens to kill your components is produced by the components themselves. As you use your entertainment system to watch movies or play music, most of the components convert much of the power they consume into heat. The more high-powered your components, the more heat they generate.

The possible exception is your amplifier. The heat output of amplifiers depends on a range of factors relating to their design and use. Traditionally, amplifiers have always been the great heat producers in any sound system. But microprocessors, which are becoming integral to most components, are not only the most sensitive to heat; they are also great heat producers themselves. The faster they are, the more power they consume and the more heat they produce. This means that amplifiers are being joined by more and more components that generate large amounts of heat.

Heat building factors

How fast heat builds up in your sound system, and how high temperatures it will reach, depends on a variety of interrelated factors.

  • The wattage of your electronics. The amount of power your system consumes directly determines how much heat it generates.
  • The size of the cabinet that houses your system.
  • The amount of airflow and air turbulence in the cabinet.
  • The density of electronics in the cabinet (i.e., how much free air is left between components and shelves)

Airflow is the key

As long as the heat can dissipate, your equipment is safe. Heat buildup has never been a problem with the traditional open stereo rack. However, audio/video cabinet enclosures, such as StudioTech’s Ultra cabinets, are becoming increasingly popular. The risk of placing equipment in an enclosure is that hot air may get trapped if it cannot escape fast enough, which will result in a continuous increase in temperature.

The key element to keeping your components cool in a cabinet-based system is airflow. A steady inbound flow of cool air and outbound flow of warm air is the key to keeping component temperature down.

Relying on Natural Airflow: Passive Ventilation

Overheating is prevented when there is sufficient cool air flowing through the cabinet to carry away any excessive heat.

In the absence of any air motion, hot air will build up in a pocket around each heat producing component in a cabinet. If this is allowed to happen, the temperature will keep rising until the system has fried itself. What prevents overheating is movement in the air. More specifically, it is the movement that allows cool air to flow in and replace the warm air.

When a stream of cooler air meets a pocket of warmer air, the warm air is caused to rise toward the top of the cabinet. A steady flow of cool air into a hot component system thus creates an ongoing, upward stream of warm air. This process is called convection.

Passive ventilation

Natural convection, as the name indicates, is the process of air replacement that takes place due to natural turbulence in the air. If your component cabinet has sufficient openings for cool air to flow in and hot air to escape, then your components will be cooled to some extent just due to the fact that the air is set in motion by any movement in the room. Whenever the air is stirred up, cool air will make its way into the cabinet and cause a flow of hot air out of the cabinet. This process is also known as “passive ventilation” – “passive,” because it takes place without any effort to facilitate it.

StudioTech’s Ultra cabinets are designed to facilitate such a process of passive ventilation. The mesh screen door, side vents, and generous rear openings jointly make possible a substantial flow of air right through the cabinet.

Creating an effective airflow

To achieve the most effective passive ventilation you must try to create a “chimney effect” by leaving an unobstructed vertical column of air where hot air can freely rise and escape. Ultra U-48 and U-60 cabinets are designed to create such an effect. Rather than reaching all the way to the sides or rear of the cabinet, the shelves inside are situated in the space between four corner pillars. This design leaves narrow “chimneys” on both sides and at the rear. However, the relatively narrow design of the cabinets places some limitation on the effect.

To ensure that heat can freely escape each component, leave some space between shelves. If you pack the interior of the cabinet densely, airflow is restricted and pockets of hot air will more easily form around your components.

The upward motion of warm air is created by the temperature differences (called “gradients”) between cool and warm air. To create the most effective airflow, you should strive to place the hotter components at the top of the cabinet. This way you create the greatest temperature contrast, and keep the warmest air closest to the exit.

Also make sure to keep the surrounding room temperature down. In order for cool air to flow into the cabinet, there must be cool air in the surroundings. And in order for hot air to rise out of the cabinet and escape, the outside surroundings must be cooler than the escaping air. To maintain the maximum operating temperature of your components at 85 degrees F it is recommended that you keep the air in the surrounding room at 75 degrees F.

Special thanks to StudioTech for this information. To read the rest of this article please visit StudioTech.com.


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Recent Forum Posts:

A14u4IA posts on August 01, 2015 06:28
Yeah after mine cooked my dvr I mounted it in the fireplace with my xbox. Too bad we want to use our real fireplace in the new place. Between the Xbox and the 1800 watt receiver I know where I will be in this drafty old house come winter.
Seriously though, it is just sitting in the open now, not near the thermostat, joy a real den, the room gets nearly 10 degrees warmer than the rest of the house. ×=:% youtube playing through Xbox not my old vizio tv app now. Tempted to vent into the attic, the heat has to go somewhere else. Guess a chromecast dongle might help a bit for youtube vids, but will be in the same boat for memorizing Nuremburg on Forza. Think the rec cooks at 400 watts just being on, I suspect the old Xbox is almost as bad. Any ideas of where to put the heat, chimmney effect is great but where does it the heat go? Anyone tried the piezo cooling cells? Should I put a cheap goldfish tank on top to soak up the heat? Is there anything that can be done without tearing into this old plaster house for another chimney?
chalkeroochy posts on January 23, 2011 04:33
My Onkyo 805 (which are known to get fairly hot) is cooled by a 2 speed Antec AV cooler, the cabinet has tinted glass doors and an open back. The antec sits directly on it.
Cools very well and very quietly on low speed. I couldn't do without it.
MidnightSensi posts on November 19, 2009 09:39
I'm pretending to work, so I have to core dump this quick:

The greater the temperature differential between the rack and the room, the less fans are needed.

Generally wider racks are better for the chimney effect. One of the reasons a wide rack runs better than a thin one, or a shelf setup, is because of the ‘chimneys’ on both sides of the rack. If you do have to use a closed wood shelf system, have the outsides of the shelves cut out along the interior walls.

The other thing that I see a lot which is a bad idea is installing vented panels between front intake equipment. This causes the air to come out the back and have a path of recirculating to the front. Shelf setups are very bad with this, because their backs are blocked and the only way for the hot air to escape is through the front of the shelf, leaving it to get recirculated into the equipment.

Rear intake equipment (front exhaust) should be separated from front intake equipment with a panel.

On shelves, often times a blower is a better selection than a fan, because blowers are capable of ‘sucking’ at higher static pressures like would be developed in a wood shelf with gear that is front to back cooled.

Also, always run a bit more intake fans than exhaust fans, because it keeps the pressure positive, which makes dust tend to move away from your equipment rather than into it.

Keep intakes away from exhaust.

Now back to work for me.
Tunup posts on November 19, 2009 04:34
Heat Buildup and Your AV Components Reply to Thread

I know more people should take heed to the heat build-up,this is why some a/v equipment gets refurbished and sold at a lower price. I bought a Oak entertainment center my first one when CD were new. The EC would only fit a 27'' tv,had a beatiful stack cabinet 8 shelves,glass door on one end and the other end held 300 vhs tapes 5 shelves wooden door opens up to them . TV fit in the middle. Back at that time only Sony made a 40'' TV and then they started to make bigger EC's. Well I didn't buy one ,but scab mine to fit a 40'' HDTV took off the VHS shelves to hold a bigger tv but on the A/V end I left on the glass door took out the backing and drilled holes for breathing. The shelves were adjustable in height. It worked because I have upgraded 3 times and this time I went really big I got some Denon furnaces (receivers) and a Pace Cable box with all the bells and whistles on it DVR etc which also throws out heat. This is a fine point you made because there are a lot of people that don't realize this . It is a major ,major point you have made. I am looking after 20 years for something exact to stack,keep dust free and look nice and that means some money. If you saw what I did you would not know it was all jigsawed up. I was shocked at the heat the cable box throws out with that sata HD in it. One more thing about the components in how they are stacked -Keep the amps or rec's on top. I was really glad to read what you pointed out for others. I just signed on to Audioholics since I just joined the Blu-ray world and upgraded tv ,rec,cable box with dvr and a blu-ray player
Theweatherman posts on November 02, 2009 14:43
AV Cooler

Have you tried using the AV Cooler offered by Antec ?
It's cool and really get's the job done ! I had continous problems with my Home Theatre Amplifyer shutting down due to over heating, however once I added this cooler into my cabinet all problems were solved.

I believe you can score at Fry's electronics for about $69
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