Bacteria, algae and other organisms thrive under warm water conditions this is obviously harmful not just for athletes but the general public in a commercial swimming pool, for competitive pools the water should be no higher than 82Â°F (28Â°C), for recreational pools the recommended maximum is 84Â°F (29Â°C).
Distortion is also used as a musical effect, particularly with electric guitars. The addition of noise or other outside signals (hum, interference) is not deemed distortion, though the effects of quantization distortion are sometimes deemed noise. A quality measure that explicitly reflects both the noise and the distortion is the Signal-to-noise-and-distortion (SINAD) ratio.
#2. The sound you are probably hearing is straight-cut transmission. The whining noise is caused by the teeth of the gears slamming together. Its nothing to worry about and the reason why it's not audible in most road cars is that they use helical gears to keep the transmission whine to a minimum.