Acoustics: Sound Fields, Transducers and Vibration, 2nd Edition

3.7. Examples of transducer calculations

Example 3.6. An ideal moving-coil loudspeaker produces 2   W of acoustic power into an acoustic load of 4   ×   10⁴   N   s/m⁵ when driven from an amplifier with a constant voltage output of 1.0   V rms. The area of the diaphragm is 100   cm². What open-circuit voltage will it produce when operated as a microphone with an rms diaphragm velocity of 10   cm/s?

Solution. From Fig. 3.35 we see that, always,

e ˜ = B l u ˜ .

The power dissipated W gives us the rms volume velocity of the diaphragm U _rms:

U rms = W R A = 2 4 × 10 4 = 7.07 × 10 − 3