Hoot (Jul 10, 2001 09:03 p.m.):
Due to the de-spiraling vanes in the Delta, it puts out better quality airflow at any speed than a plain axial fan. The problem with all the Focused Flow Delta fans is the fact that there is an actual tonal quality to the noise they make. It is unavoidable with static vanes. By tonal quality, I mean the noise is not broad spectrum audio. The majority of it is concentrated in a specific frequency range. Your brain tunes out broad spectrum noise very well since it is subjected to it all the time, to a greater or lesser degree. A single tone is more like "Chinese Water Torture". It wears upon you. You can get accustomed to it, but you never totally like it. The tone frequency as well as the volume of the noise from a Focused Flow fans gets lower in frequency the slower the motor spins, but the effectiveness of the airflow stays surprisingly high. With a rheostat and the case cover on, you can reduce the noise from the fan 50% and only see a 1 or 2 degree increase in temps. If you have a Web Site where I can send a .wav file, I'll record it alongside the Sunon 80mm case fan at different speeds so you can get a relative level to compare it to.
Hoot
