If I had one wish as a broadcast engineer with a degree in audio and acoustics, it would be that people would stop saying "dB" without quoting the standard reference value. A dB without its reference value is simply a ratio. Kills me.
I guess you meant 101 dB ref 10^-12 watts, or more likely because you said at 1m you might have meant dB SPL relative to 20uPa.
Nerd goes back in his box.
Oh, and to the guy who said this
turningscrews wrote:
lacticturkey wrote:
Isnt that a 2 different topics?
Energy in sound vs energy it costs to make sound?
Like the portable speakers - it takes 6w to make some sound.... Sure it's not enough sound to heat a coffee, but it's still 6w to make it
No. Same, dumb, topic.
Not the same thing at all, not even close. Read about entropy and the efficiency of energy transducers.
So much bad science on here.
I thought the OP was a reasonable question. Whatever form the waste energy ends up being in - acoustic or heat - it is still waste energy and indicative of losses in the system. The question is, are these
additional losses or would they otherwise manifest in some other way in another, quieter, wheel... eg as heat. Not necessarily, I don't think. Imagine a really really wobbly wheel that makes the rider bob up and down and throws energy away willy nilly vs a simple stiff spoked wheel. One is wasting more energy than the other because there is a degree of freedom or a vibration taking place that would otherwise not be. Now imagine that it is just a small vibration that is manifest acoustically. Could still be a difference in the system loss vs a wheel that doesn't vibrate the same way, even if it is just small. I kind of think if it was affecting anything at all it would be the "power to spin" part of the system, and maybe it loses something vs another wheel. But then it gains in other ways, and on balance it is worth it I'm sure. I thought it was a good question.
As somebody else said, unless you have a perfectly efficient acoustic-mechanical transducer (doesn't exist) then it costs more mechanical watts in the drive train than you get acoustic watts in the air. For example, a well designed electroacoustic transducer (ie a loudspeaker) might have a sensitivity north of 90dB (no reference needed, this IS a ratio!) or efficiency around 2-3%. BUT, the actual values being considered are tiny. A single watt of acoustic power is the Sound Power Level equivalent of a heavy thunderstorm or a symphony orchestra. A hairdryer, for example, represents about 10^-6 watts.
So in summary, a good question but don't fret it.