during cost analysis you will also compare the proposed cost elements with i actual costs ii previous cost estimates for same or similar work iii other cost estimates iv independent government estimates and v forecasts of planned expenditures
How Decibels Apply to Music and Sound. In music, decibels are a measurement of Sound Pressure Level (SPL). When we say the speakers at a rock concert are playing at 110dB, what we really mean is that theyâre playing at 110dB SPL. Since the decibel is only a ratio, 110dB is actually a comparison to a different number: 0 SPL.
The deciBel (Î²) is commonly used as the smallest difference in loudness that can be detected. The reference intensity I0 = 10 -12 W.m -2 is the (alleged) quietest sound that can be heard. Only about 10% of people can hear this 0 dB sound and that only in the frequency range of 2kHz to 4kHz. About 50% of people can hear 20dB at 1kHz.