Nicole Kidman and Keith Urban have a new baby, courtesy of a surrogate ... TMZ has learned. Sources tell us ... the baby was born at Centennial Medical Center in Nashville on December 28, 2010.
Quick Answer. When talking about dishwashers, decibels refers to the noise level a dishwasher produces when it is in operation. The quietest dishwashers have decibel ratings around 40 and slightly below, while the noise level in decibels of a normal conversation is about 60.
The relationship between sound and noise levels is generally described in terms of a signal-to-noise ratio. With a masking noise level between 35 and 100 dB, the threshold for 100% intelligibility is usually a signal-to-noise ratio of 12 dB. The speech signal ranges from about 200-8000 Hz, while human hearing ranges from about 20-20,000 Hz, so the effects of masking depend on the frequency range of the masking noise.