Each cooler will be tested at night as it is naturally the quietest time of the day. A decibel monitor is placed at 30cm away from the cooler which is much closer than you would probably be sitting but it allows for consistent readings in my eyes. The system is left to idle for five minutes to ensure it is at its most rested work load and then the readings are taken. The fans are on PWM mode rather than ‘x’ volts as some fans will not spin without it getting its start voltage. The PWM curves are set to the default ones that are supplied by the Hero’s BIOS.
To find out how much noise the fan(s) will make under a full loading, I plug them straight into a 12v line to ensure that they are running at full speed to give you an idea of how much noise is created at maximum RPM ranges.