33
MOUNTING & PLACEMENT
The placement of any recorder can have a significant effect on the results of a survey. It is
important to consider the location and height of the recorder. The best signals will be
obtained when the microphone is in the open away from other objects and pointing in the
direction of the animal emitting vocalisations.
For bat surveys, recorders are typically placed in or beside a
‘
flyway
’
, a corridor where bats will
fly through or beside vegetation. You can place your recorder anywhere bats will fly,
depending on your survey goals or target species. Avoid placing the recorder inside dense
vegetation where bats cannot fly. Avoid having vegetation or other objects between the
recorder and the bat
’
s expected flight path, or close beside the recorder, as echoes will also
be recorded. Also consider insect noise when choosing a location, insects close to the
recorder can generate a lot of unwanted noise files.
We recommend that the Chorus is mounted vertically (refer to the section on
weatherproofing) so that any rain water runs off the microphone/s and doesn
’
t settle on the
element/s. Also make sure that the magnetic lanyard or the device itself is not being blown
around in the wind as this may create unwanted noise on your recordings. It is also important
to avoid surface noise, such as vegetation brushing against the recorder case or microphone.
You can also purchase a gooseneck microphone extender, which we recommend for
mounting the ultrasonic microphone, so it can be directed away from flat reflective surfaces.
The Chorus case is designed so that the device can be padlocked closed. A lockable metal
security box is also available for purchase from Titley Scientific.
EQUALIZATION & CALIBRATION
In some situations where multiple recorders are deployed, it may be a requirement to ensure
all the recorders being used are equalized to the same trigger sensitivity. This is important
whenever quantitative comparisons of acoustic activity will be made. Levels of sensitivity will
vary among recorders due to differences in age, wear and so on. Recorders can be equalized
using a
‘
Chirper
’
which emits an ultrasonic signal at a constant frequency and amplitude.
Acoustic microphones can be tested using a standard sound level meter calibrator that
outputs a 1kHz tone at 94dB.
Summary of Contents for CHORUS
Page 1: ...CHORUS User Manual Version 1 0 ...
Page 7: ...7 EXTERNAL FEATURES ...
