Friday, June 18, 2021

Review Of The LunaBat DFR-1 Pro Bat Detector Part 2 of 2

Review of The LunaBat DFR-1 Pro From Animal Sound Labs Part 2 of 2 
I expect Readers to find much of the User Manual to contain rather interesting bits of information. Some additional pages of interest from the User Manual include:
3.11 Correction of the recording level (Rec Level) AKA: (Changing the recording level [Set Rec Level]). Page 16
4. Detector firmware update (Firmware Update). Page 17
5. Useful tips. Page 19
6. Approximate working times in different conditions.* Page 20
*Of particular interest, if you're a battery geek (like me) - Two excellent brands of batteries are mentioned as well.

The LunaBat DFR-1 Pro is a good product for those in need of a handheld, professional-level bat recorder; which may also be used as an unattended detector, in many instances. It is robustly built, and can be relied upon to record bats in almost any situation or environment.
I've been informed that the very latest version of this detector, has had the buttons modified to respond to less pressure, and the amount of button travel has been reduced.
The illumination of the LEDs has also been made more energy efficient. 
As mentioned in Part 1 of this (2-part) review, the unit is highly customizable. Amoung the features are:
  • High-pass and low-pass filters
  • Full spectrum  High Pass filters
  • Frequency division high pass filters

As indicated in the user manual when the full spectrum high pass filter is turned on, certain audible sounds will not be recorded, such as those produced at frequencies below 15 kilohertz. Things like conversations, walking on dry grass and / or leaves, and other undesirable sounds.

Use of this filter is recommended during recording attempts in strong winds, or when one is in fact walking on dry leaves, dry grass, etc.

With the full spectrum high pass filter enabled, the lower-frequency limit of recorded signals will be approximately 150 Hertz, which enables things like verbal comments, other voices, and other  normally audible sounds. 

During my Summer of testing, I rarely came across a situation in which I needed to enable it. When using even the default settings, there weren't many instances where sounds other than bats triggered the LunaBat. I would just hit 'OK' to record, and walk...

If you have dry leaves underfoot during your survey, bat-walk, etc., then in addition to the filter, you can adjust the trigger level. Regardless of the mode I used, no background hiss was heard from this detector. 

All of this is covered in more detail in part 3.9 (page 15) of the user manual.

It has demonstrated excellent sensitivity. As you will see, when I add some results below, in the form of sonograms, and recordings. ...Thank you for your patience...

Now, although Animal Sound Labs graciously provided a list of links to free sound analysis software - On their Download page (under the heading 'Programs').
I decided to go ahead and utilize the latest version of Kaleidoscope (Version 5.4.2) from Wildlife Acoustics.
Especially since an update post on this excellent bat call auto-ID software is on my agenda.
Eptesicus Fuscus (Big Brown Bat)
as seen with WA's Kaleidoscope Pro software.

Lasionycteris Noctivagans (Silver-haired bat

Other neat features worth mentioning are:
A standard (3.5mm) audio cable may be used to connect the detector to a cell phone (w/ Mic Input) - Allowing Apps such as SpectralProAnalyzer to display live spectrograms. You may also experiment with similar, spectrogram-producing Apps.
Once the GPS/GNSS (blue) indicator comes on, maximum signal strength (exposure to the open sky) is no longer needed.
The volume setting is remembered after the unit is powered off; and even during battery replacement (if completed in under ~1 minute).
The length of each individual recording may be set to anywhere from 3 seconds to 60 minutes. 
As always, I encourage readers to do their research, and shop around. Again, watch this space for soon-to-be-posted spectrogams!
To be continued...

Happy bag detecting!

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