acoustical power การใช้

• Even a relatively modest 3dB increase / decrease in sensitivity corresponds to a doubling / halving of acoustical power.
• While a doubling / halving of perceived loudness corresponds to approximately 10 dB increase / decrease in speaker sensitivity, it also corresponds to approximately 10X multiplication / division of acoustical power.
• Standard measurement practice of speaker sensitivity is driving 1 watt electrical power to the source, with the receiver 1 meter away from the source, and measuring the resulting acoustical power in dB relative to the threshold of hearing ( defined as 0 dB ).
• Many high quality domestic speakers have a sensitivity between ~ 84 dB and ~ 94 dB, but professional speakers can have a sensitivity between ~ 90 dB and ~ 100 dB . An'84 dB'source would require a 400-watt amplifier to produce the same acoustical power ( perceived loudness ) as a'90 dB'source being driven by a 100-watt amplifier, or a'100 dB'source being driven by a 10 watt amplifier.
• When measuring in'half space', the boundary of the ground plane cuts the available space that the sound radiates into in half and doubles the acoustical power at the receiver, for a corresponding 3dB increase in measured sensitivity, so it is important to know the test conditions . ? dB change in measured sensitivity also corresponds to a similar doubling / halving of electrical power required to generate a given perceived loudness, so even deceptively'minor'differences in sensitivity can result in large changes in amplifier power requirement.