The Song Meter Mini Bat is built with the same microphone element used in our SM4BAT FS ultrasonic microphone, the SMM-U2. In many recording scenarios, the recordings produced by an SM Mini Bat will be nearly identical to those produced by a Song Meter SM4BAT FS paired with an SMM-U2. However, the SM4BAT FS uses more advanced recording and trigger circuitry that gives it an edge over the SM Mini Bat.
For unattended bat recorders like our ultrasonic Song Meters, the ability of the recorder to detect a passing bat and start recording is as important as the quality of the recordings it produces. Both the SM4BAT and the Mini Bat use adaptive triggering. The recorders are listening for ultrasonic sounds loud enough to be detected through the general noise level of the surrounding environment. When they detect a loud-enough sound in this range, they start recording until that sound is no longer detected. There is a difference, however, in the type of triggering the records employ. The Mini Bat (like almost all other bat detectors on the market) uses a broadband trigger where the bat has to exceed the background noise across the ultrasonic spectrum. The SM4BAT-FS uses a narrowband trigger breaking and splits the frequency range up into many narrow bands, monitoring each band separately. When a sound is detected in any of the bands in the user-specified trigger frequency range, The SM4BAT starts recording. What this means is that if there is persistent background noise in some portion of the ultrasonic spectrum, such as from insects or nearby electronic equipment, the SM Mini Bat’s trigger sensitivity will be affected by that background noise, regardless of its vocalization frequency range. In noisy environments, the SM4BAT FS will tend to produce more bat recordings than the SM Mini Bat.