I flew jets in the USAF for over 6K hours, so my hearing is not the greatest either, but I can hear this one
When I test my multicopters in the house, I have to put tape over the that buzzer or my family complains. Bright LED's work for some too if the sun is behind you. Conservative timing on your Tx and voltage readout via data-link and/or OSD are the best for keeping track of the remaining power. Always allow a 2 minute reserve for landing, or land as soon as you hear the buzzer. Pushing the battery reserve is probably one of the most frequent causes for most Gents multicopter crashes. That and not setting the ESC's to NiMh and low or no cutoff get the predictable bad results.
Quadrocopter and Tricopter Info Mega Link Index
Originally Posted by Tom Frank
Thanks for the links, Jim. The louder buzzer would be good if it were a lower frequency. My hearing drops off rapidly over 1000 Hz. I put a "louder" 2700Hz alarm beeper in my TX, and can barely hear it (it's highly directional as well). I'm thinking maybe a very bright LED (or several, one on each arm) might be a better solution, even in daylight?