This might be a pretty stupid question but does the volume of the audio being recorded affect the battery consumption for a battery powered pre-amp and/or ADC? If you just leave the device operating in silence would you expect the battery to last longer than if it was recording Slipknot at 140dB? I would assume that if the device is having to do more work it would drain a battery faster. Is this correct or does it not make any appreciable difference?
Simple physics would lead me to believe that if there is a low signal coming out then it must be using less energy than if a steady stream of digital data was being generated. I found information concerning radio and other audio players and the conclusion there was that battery power dissipates faster with louder volume but that's because the batteries are driving an amplifier and speakers. But a pre-amp is also an amplifier of sorts so I assume the same is true.
If nothing else there is less battery being used to power indicator LEDs etc.
Bottom line, if I test battery usage of a device in silence can I assume that this is the best battery life I can expect to get under any conditions?