Reducing Computer Fan Noise

One of our members, Norman Cousins, has kindly prepared an article on how he reduced his computer fan noise. As the technical details such as resistor values will vary between computers, he is willing to discuss specific cases and can be reached through the Society's contact information. His contribution follows:

My present computer, bought in August 1998, is a 333 MHz Pentium II PC in a tower case. It has 3 fans (CPU fan, power supply fan, case fan) which produced a lot of wind noise, whine and vibration. That became very wearing at a range of two feet! After a couple of years I replaced all the fans with new similar ones, with no improvement.

Expensive fans are available which are claimed to be very quiet, or that are temperature controlled. But I heard conflicting reports about them, and it didn't seem worth the risk, since they would have to be mailed from the States or Europe (I live in Vancouver BC).

I realized that the fans are rated to keep the computer at a safe temperature on the hottest of days, and could probably run much slower in this temperate climate. To monitor the temperature of the computer I bought a small battery- powered automobile temperature-measuring unit (from Canadian Tire).

Each fan uses a 12 V DC motor that runs more slowly if less voltage is applied. One way is by connecting resistance in series with the motor; cut one wire to the motor and connect the resistance across the gap. The lower speed is quite safe for the motor.

I recorded the temperature of the CPU heatsink as I added resistance to slow the CPU fan. I repeated this as I slowed the case fan. Then I opened the power supply cover (this voids the warranty and poses a shock hazard) and recorded the temperature of an internal heat sink as I slowed the power supply fan. Each fan could be slowed a great deal without causing much temperature rise.

Finally I mounted 3 variable resistors at the front of the case, to run each fan from slow up to full speed, and left the temperature sensor permanently on the CPU heatsink.

With all 3 fans running slowly there has been no sign of overheating and the noise level is dramatically lower, only just audible.

Automakers Feed Boom Car Frenzy

Ford Motor, Mazda and Nissan are teaming with major audio companies - including Panasonic, Kenwood and Pioneer - to offer 400-watt-plus stereo systems in entry- level cars. The typical factory-installed audio system in a car is a radio/CD/tape player combination with 100 to 200 watts of power and six speakers.

The systems being offered in some Ford limited-edition 2003 models start at about 350 watts and go to 1,140 for the Mach 1000 option available in the Ford Mustang, which has six amplifiers mounted in the trunk along with subwoofers.

Mazda sells the 2003 Mazdaspeed Protege, which features a 450-watt Kenwood system with subwoofers and seven speakers. It's part of a $4,000 option that includes a turbo-charged, 170-horsepower engine, and wheels, tire and shock improvements.

Nissan has teamed with Rockford Fosgate for upgraded audio in its Sentra SE-R compact sedan and Frontier and Xterra trucks. Fred Suckow, senior manager for marketing at Nissan, says the company expects 10% to 15% of buyers will choose the audio system upgrades.

That sound capability aimed at 16- to 23-year-olds concerns the insurance industry. "Teenagers are the most accident-prone group within the driving population, and any kind of potential distraction is going to be an issue," says P.J. Crowley, of the Insurance Information Institute. "This certainly adds to the potential for distraction. How that will ultimately translate into accident rates remains to be seen."

-Earle Eldridge, USA Today, September 10, 2002
Contacts: www.ford.com, www.mazda.com, and www.nissanmotors.com

Perhaps the Insurance Corporation of BC should be very concerned about these cars, due to tragedies like the following: An afternoon crash ended tragically February 7, 2003 when an ambulance on an emergency call collided with a car in Victoria, BC, killing the car's driver. On the CKNW 98 February 8, 2003, 8 am news broadcast it was reported that witnesses said the car stereo was so loud that the driver quite possibly would not have heard the ambulance siren.

Right to Quiet Society Newsletter, Spring 2003

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