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 rival 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 in two ways.
The SM4BAT FS records WAV files with an effective bit depth of 16 bits, while the SM Mini Bat has an effective bit depth of 12 bits. This means that the dynamic range of the SM Mini Bat (the difference between the quietest and loudest sounds it can record) will be more constrained than that of the SM4BAT FS. In practical terms, this means that it will be easier to record very distant or quiet bats on an SM4BAT FS than on an 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. The SM Mini Bat uses a triggering mechanism shared by many bat recorders on the market, listening for ultrasonic sounds loud enough to be detected through the general noise level of the surrounding environment. When it detects a loud-enough sound in this range, it starts recording until that sound is no longer detected. The SM4BAT FS takes this a step further by splitting the frequency range up into many narrow bands. It monitors each band separately, and when a sound is detected in any of the bands in the user-specified frequency range, it 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 for any passing bat, regardless of its vocalization frequency range. In noisy environments, the SM4BAT FS will tend to produce more bat recordings than the SM Mini Bat