Noise levels - Sound pressure readings
Acoustic Performance
With a certified dBA meter, we measure how many DBAs originate from the PC. It's slightly subjective as there is always noise in the background, from the streets, from the HDD, PSU fan, etc so this is by a mile or two, not a precise measurement. You could only achieve objective measurement in a sound test chamber. Take this measurement as an indication, not a precise measurement, please.
The human hearing system has different sensitivities at different frequencies. This means that the perception of noise is not at all equal at every frequency. Noise with significant measured levels (in dB) at high or low frequencies will not be as annoying as it would be when its energy is concentrated in the middle frequencies. In other words, the measured noise levels in dB will not reflect the actual human perception of the loudness of the noise. That's why we measure the dBA level. A specific circuit is added to the sound level meter to correct its reading in regard to this concept. This reading is the noise level in dBA. The letter A is added to indicate the correction that was made in the measurement. Frequencies below 1kHz and above 6kHz are attenuated, whereas frequencies between 1kHz and 6kHz are amplified by the A weighting.
| TYPICAL SOUND LEVELS | ||
| Jet takeoff (200 feet) | 120 dBA | |
| Construction Site | 110 dBA | Intolerable |
| Shout (5 feet) | 100 dBA | |
| Heavy truck (50 feet) | 90 dBA | Very noisy |
| Urban street | 80 dBA | |
| Automobile interior | 70 dBA | Noisy |
| Normal conversation (3 feet) | 60 dBA | |
| Office, classroom | 50 dBA | Moderate |
| Living room | 40 dBA | |
| Bedroom at night | 30 dBA | Quiet |
| Broadcast studio | 20 dBA | |
| Rustling leaves | 10 dBA | Barely audible |
The fans are not audible while the computer is idle or load. The results remained very impressive once we put the CPU through its paces with many full wPrime runs. So it begs the question, what happens when we overclock our computer? Well, we only see an increase in DBa levels when we apply 1.35V voltage to the processor and overclock it.
