The D500X is an ultrasound recording unit intended for long-term, unattended recording of bat calls. In contrast to time expansion bat detectors, the D500X records full-spectrum ultrasound in real time with virtually no gaps between recordings. The recorder is equipped with four slots for CF cards, which typically makes it possible to leave the unit in the field for more than a month. The triggering system allows the device to automatically start recording as a sound is detected.
The D500X is supplied in one of two versions: The Mk I version includes an internal microphone and has an external microphone jack socket. The Mk II version includes an external microphone and does not have an internal microphone. The Mk I is powered by 4 x AA batteries and can record for up to 5 nights. The Mk II version uses C cell batteries and can record for up to 14 nights. Both of these deployment times are dependent on the batteries being used. An external DC power source can be used.
The external microphone can be extended using XLR cables up to a distance of 100m without experiencing any discernible signal loss.
The recording length can be selected in steps from 0.3 up to 20 seconds. In order not to fill the card too fast at locations with high activity, a minimum time between two recordings can be applied. The recorder is normally operated in a low-power mode with no pre-trigger (i.e. the recording starts as the sound exceeds the chosen threshold level), but both pre-and post-trigger functions are available in the standard (not low-power) mode. The D500X stores the bat calls in time stamped wav files.
The D500X comes in a rugged and weather-protected aluminium housing.
Various accessories are available, such as an external microphone with extension cable up to 100 m and a soft protection case with hooks to hang the unit in e.g. a tree.
Type: Direct, high-speed recording; Microphone: Advanced electret, jack for external microphone; Frequency range: 15 – 190 kHz (500 kHz sampling rate, high-pass filter enabled); Connections: External microphone, external trigger, external DC supply; Timer: Four on/off periods per day; Batteries: 4 x AA (Mk I) or 4 x C (Mk II), Alkaline or NiMH recommended; External DC supply: 5.5-8 V, typically ca. 200 mA (average, when recording), depends on CF card type and number of CF cards; Size: 165 x 170 x 53 mm, excl. connectors etc.; Weight: 1.2 kg incl. batteries and front panel cover.
ADC resolution: 16 bits; Anti-aliasing filter: Yes, 8th order, 190 kHz cut-off frequency; Sampling rates: 44.1, 300, 500 kHz (optimized for 500 kHz); Recording length: 0.3, 0.5, 1, 2, 3, 5, 10, 20 sec or manual recording; Recording medium: CF card, 4 slots