Introduction

I’m writing this article because over the past few years I’ve become more and more conscious of computer noise – it’s become a distraction, and it has a noticeable physiological impact. I find that today’s computers are so noisy they irritate me unless I’m absorbed in work or conversation. The problem becomes even more intense at home, especially at night when your place is relatively quiet and the insistent hum from your computer is the most noticeable source of noise in the environment around you.

Computer noise, then became my enemy.

The purpose of this article is to introduce you to the method that I, and Tweakfactor will use to measure noise from various products that we will be reviewing. To begin, let me state that we will not just rely in subjective “measurements”, since any measurement made by subjective means cannot possibly be as reproduceably accurate as measurements taken by instruments.

Measuring noise: Sound Level Meters

Noise is measured in Decibels, or dBA. There’s actually 2 common weightings of the decibel scale, the “A” weighting and the “C” weighting. In our area you’ll almost exclusively encounter measurements in the C weighting.

To measure noise you can purchase a Sound Level Meter. These are precision instruments that help you measure the level of volume in the environment. After some research we settled on using the HHSL-1 by OMEGA. OMEGA is a maker of many different measurement instruments, including 2 sound meters. The HHSL-1 retails for $149USD – this is an expensive instrument, but make no mistake, the HHSL-1 is not nearly as sensitive as you would want it to be if you could measure TRUE 20dBA coolers. That’s because on the low scale, the HHSL-1 is only accurate down to 35dbA, though as you’ll find out, we were able to measure down to 26.5dbA.

Above: From Left to Right: the Omega HHSL, RadioShack's Meter, and the Pulsar 30.

There ARE tools that are spec’d to measure down to 25dbA and even 20dbA, but these can run into the thousands of dollars. Just check out the Pulsar 30 by Pulsar Instruments, this baby sells for $2500USD and more!

Because we’re dealing with noises that are simply irritations in quiet environments, we can’t really rely on some of the instruments that cater to more common uses. Radio Shack for instance, sells a Sound Level Meter for around $49USD (or $89Cdn for us Canadians :)), but this device measures noise only down to around 50dBA – and trust me, if you want to measure for a peaceful lack of computer noise, you’re going to need something more sensitive.