Neil McCauley
27-07-2017, 09:05
Paul McGowan:
Thanks to reader John McRee for suggesting the title of today’s post. Yesterday we learned we need 8 times more power to reproduce speech than we do sine waves – which may then surprise people that loudspeaker manufacturers continue to use sine waves as a basis for their efficiency measurements. It certainly surprises me since we don’t listen to sine waves and one might question the value of such measurements.
If speech needs an 8:1 increase in amplifier power over sine waves, how about music? Try 50:1 on for size. The crest factor of music is generally around 20dB where speech is 12dB and sine waves are 3dB. Remembering that each 3dB increase in crest factor requires the amplifier power to double, this means that a reasonably efficient loudspeaker, say 90dB efficient, needs 50 watts of power to reach musical peaks of 90dB, but only 1 watt to play the same loudness level sine wave. 50 to 1.
Now we should ask ourselves several questions: chief among them would be .....
http://www.hifianswers.com/2017/06/music-math/
Thanks to reader John McRee for suggesting the title of today’s post. Yesterday we learned we need 8 times more power to reproduce speech than we do sine waves – which may then surprise people that loudspeaker manufacturers continue to use sine waves as a basis for their efficiency measurements. It certainly surprises me since we don’t listen to sine waves and one might question the value of such measurements.
If speech needs an 8:1 increase in amplifier power over sine waves, how about music? Try 50:1 on for size. The crest factor of music is generally around 20dB where speech is 12dB and sine waves are 3dB. Remembering that each 3dB increase in crest factor requires the amplifier power to double, this means that a reasonably efficient loudspeaker, say 90dB efficient, needs 50 watts of power to reach musical peaks of 90dB, but only 1 watt to play the same loudness level sine wave. 50 to 1.
Now we should ask ourselves several questions: chief among them would be .....
http://www.hifianswers.com/2017/06/music-math/