I will be monitoring bats with AudioMoths, and in order to determine the range the device can detect wildlife I want to perform an active test in all directions from the device with a speaker (5m, 10m, 15. etc...).
I only have a regular speaker, which is unable to produce sounds at frequencies bats generally produce calls. I was wondering if you have any advice how to, considering this limitation, still perform as reliable a test as possible? How much decibels should the speaker produce? On what frequency (up to +- 16kHz) should I play tones?