Wildlife Acoustics SM2BAT User manual

Song Meter SM2BAT
192kHz Stereo or 384kHz Mono
Ultrasonic Recorders
Wildlife Acoustics, Inc.
www.wildlifeacoustics.com

Copyright © 2009-2011 Wildlife Acoustics, Inc.
Rev. 5/17/11
All rights reserved. Wildlife Acoustics is registered in the U.S. Patent and
Trademark Office. Song Scope, Song Meter, SM1, SM2, SM2BAT, SMX, and
WAC are trademarks of Wildlife Acoustics, Inc. All other trademarks are the
property of their respective owners. Patents pending.

Copyright © 2009-2011 Song Meter SM2BAT iii
About This Document.......................................................... 1
Overview............................................................................... 1
SMX-US Microphone.......................................................... 2
Notes on Weatherproofing............................................... 2
Directionality and Frequency Response.......................... 3
Cables............................................................................... 5
Power Consumption ............................................................ 5
Using SM2BAT to monitor Bats......................................... 6
Simple One-Channel Configuration ................................ 6
Jumper Settings.......................................................... 6
Schedule..................................................................... 7
Audio Settings............................................................ 7
Stereo Ultrasonic Recording............................................ 9
Mixed Ultrasonic and Acoustic Recording...................... 9
Stereo Mixed Recordings........................................... 9
Scheduled Mixed Recordings.................................... 10
Post Processing................................................................ 11

About This Document
1 Song Meter SM2BAT Copyright © 2009-2011
About This Document
This document describes the use of the SM2BAT 192kHz stereo and SM2BAT
384kHz mono daughter cards for the Song Meter SM2 acoustic monitoring and
data logging platform.
Refer to the Song Meter SM2 User Manual for detailed information on using the
Song Meter SM2 platform. This document is intended as a supplement and
assumes you are already familiar with the Song Meter’s operation.
You will also want to download and install the latest Wac2Wav postprocessing
software and Song Meter Configuration Utility software from the downloads
section of our website at www.wildlifeacoustics.com.
Overview
The SM2BAT 192kHz stereo or 384kHz mono daughter card is installed on the
back of the SM2 motherboard and provides a high-speed 16-bit digital sampling
capability.
The audio input to the SM2BAT comes from the output of the two-stage
preamplifier on the SM2. Refer to the section on Amplifier Configuration
Jumpers in the Song Meter SM2 User Manual for more information about
configuring the analog high-pass filters and gain settings. Note that the
SM2BATaudio signal is notroutedthrough thethird-stage amplifier configured
by the left and right gain parameters in the settings menu. Therefore, the gain is
configurable only with the SM2 jumpers to +0, +12, +24, +36, +48, or +60dB,
and the third stage gain settings will have no effect. For monitoring bats with the
SMX-US ultrasonic microphone, the +36dB or +48dB setting is recommended.
Use +24dB on the first stage and either +12dB or +24dB on the second stage to
get the desired +36dB or +48dB amplification.
The SM2 automatically detects the presence of the SM2BAT daughter card. If
present, the 192,000 or 384,000 Hz sample rate choice is added to the list of
possible sample rate settings. In addition, the SET advanced scheduling
command can also configure the 192,000 or 384,000 Hz sample rate as part of
an advanced schedule.
When 384,000 Hz sample rate is selected, the SM2BAT 384kHz mono daughter
card is used to sample the audio stream from the left channel. When the 192,000
Hz sample rate is selected, the SM2BAT 192kHz stereo daughter card is used to
sample the audio stream from the left and right channels. Otherwise, the SM2
uses its on-board codec to sample at audio rates up to 48,000 Hz.

SMX-US Microphone
Copyright © 2009-2011 Song Meter SM2BAT 2
SMX-US Microphone
The SMX-US is an ultrasonic microphone designed for terrestrial monitoring
applications, specifically for recording the echolocation calls of bats.
Notes on Weatherproofing
The transducer inside the SMX-US microphone can be permanently
damaged if it is exposed to water in the event that the weatherproofing
fails.
To protect the transducer, there are trade-offsbetweenultrasonic sensitivity
and weatherproofing.
The SMX-US features several layers of protection. First, a porous
membrane transparent to ultrasound prevents unpressurized liquid water
fromenteringthe microphone. However,themembraneisratedtoonly0.07
lbs/in2or 5g/cm2. This is easily exceeded by wind-blown rain. The foam
windscreen provides a critical second layer of protection to absorb the
impact of wind-blown rain so that only unpressurized water reaches the
membrane effectively protecting the transducer. When dry, the foam
windscreen is almost transparent to ultrasound with a loss of only 2dB.
However, the loss increases with frequency when wet, and will effectively
block ultrasound if it then freezes.
The membrane is also fragile. The foam windscreen adds a layer of
protection against insects, rodents and birds who will tend to nibble on the
windscreen instead of the membrane.
We strongly recommend operating the SMX-US with the windscreen, and
replacing the windscreen if it becomes fully or partially eaten.
We also recommend positioning the microphones so that they point parallel
to the ground, or even slightly downward. In this configuration, even if the
windscreen is absent and water penetrates the membrane, the water should
not collect in sensitive areas inside the microphone and there is a good
chance that the transducer will survive. If you suspect that water may have
entered the microphone, you should avoid handling it until it has
completely dried out. Otherwise water could change position and come in
contact with the transducer resulting in damage.
If you are deploying the SM2 in field conditions expected to remain wet or
frozen, you may want to operatethe SMX-US microphone without its foam

SMX-US Microphone
3 Song Meter SM2BAT Copyright © 2009-2011
windscreen and instead implement your own weather protection to protect
the membrane from wind-blown rain. Again, we recommend that you aim
the microphone horizontally or downward (not upward) to reduce the risk
of damage should weatherproofing fail.
Directionality and Frequency Response
The SMX-US is an omnidirectional microphone and is therefore ideally
suited to unattended monitoring in which the precise direction of bat
activity may not be known in advance. The following graph illustrates the
typical pick-up pattern:
SMX-US Directionality
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0015 30
45
60
75
90
105
120
135
150
165
180
195
210
225
240
255
270
285
300
315
330 345
40khz 80kHz 120kHz

SMX-US Microphone
Copyright © 2009-2011 Song Meter SM2BAT 4
TheSMX-USissensitiveto frequencies over 150kHz.Thegraphshowsthe
typical frequency response and noise floor of the SMX-US microphone.
Some additional attenuation can be expected if the microphone windscreen
is wet, especially in higher frequencies:
SMX-US Frequency Response
-140 -120 -100
-80 -60 -40 -20
0
10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000 90,000 100,000 110,000
Hz
dBV/pa
Sensitivity Noise Floor

Power Consumption
5 Song Meter SM2BAT Copyright © 2009-2011
Cables
The SMX-US is a powered microphone with low impedance and can drive
cables up to 100 meters without a preamplifier and without any noticeable
loss at frequencies up to 120kHz.
The SMX-US microphone can be either connected directly to the SM2
enclosure without any cable or extended on one or more lengths of our
standard one meter, ten meter and fifty meter cables up to the maximum.
For best results, the SMX-US microphone should be mounted on a cable
and placed away from the Song Meter enclosure or other hard objects in
order to reduce echos.
Power Consumption
The following table illustrates the typical power consumption for different
configurations and settings. Note that actual consumption may vary depending
on flash cards, variation in electronic components, and other variables:
High quality Alkaline D cells can deliver about 14,000mAh capacity at 20° C.
Withcompressionandtriggers,thistranslatestoabout95hoursrecordtimewith
192kHz mono, 70 hours record time with 192kHz stereo, and 75 hours record
time with 384kHz mono. Longer deployments are possible with larger external
batteries using the Song Meter SM2PWR power adapter sold seperately.
When the SM2BAT daughter card is not being used, for example when the Song
Meter SM2 is configured for sampling rates at or below 48kHz, it will still
consume some additional current when recording compared to an SM2 without
the SM2BAT card installed. In the case of the 192kHz stereo card, 25mA of
additional current is used. In the case of the 384kHz mono card, 15mA of
additional current is used.
Rate and
Channels Uncompressed Compressed Compressed w/ Trigger
192kHz x 1 115mA 145mA 150mA
192khz x 2 115mA 175mA 195mA
384kHz x 1 90mA 155mA 185mA

Using SM2BAT to monitor Bats
Copyright © 2009-2011 Song Meter SM2BAT 6
When the Song Meter is sleeping between scheduled recording events, the
SM2BAT is also powered down and total current consumption is typically less
than one milliamp.
Using SM2BAT to monitor Bats
Simple One-Channel Configuration
Theconfigurationdescribedbelow is availableasanexample configuration
in the Song Meter Configuration Utility distribution, “SM2BAT-192-
MONO.SET” for the 192kHz stereo model or “SM2BAT-384-
MONO.SET” for the 384kHz model. For the SM2BAT to be able to
determine your location's sunrise and sunset times, it is necessary to input
your latitude, longitude and timezone. These are found under location
settings. You may also want to set a device-specific prefix.
The SM2 Terrestrial Ultrasonic Packages come with one SMX-US
ultrasonic microphone. The easiest set-up is to connect the microphone
directly to the left microphone connector on the SM2 enclosure and mount
the SM2 on a tree or post at the field site. You can also extend the
microphone on a cable up to 100 meters away from the enclosure.
With one channel using compression and triggering, you can get about 95
hours of record time at 192kHz or 75 hours at 384kHz out of the internal
four “D” alkaline batteries, over one week of night time monitoring. In a
typical night with bat activity (and no rain or gusty wind), you will need
about 0.5GB per night for a stereo recording. But even with gusty wind
causing false triggers, you will probably only need about 2GB per night.
Therefore, a single 32GB card should easily last for 2-8 weeks.
For longer deployments, you can use a larger external power source. With
4x32GB flash cards, you should have enough storage to last 50-250 nights
depending on conditions.
Jumper Settings
You should configure the preamplifier jumpers with the analog high-
pass filter set to 1kHz and the gain set for +48dB or +36dB. Refer to
the Song Meter SM2 User Manual for details. The dynamic range can
be increased by using +36dB gain to avoid clipping stronger signals
without significant impact to quieter signals. +48dB gain will deliver
a stronger signal with a slight improvement to high-frequency signal-

Using SM2BAT to monitor Bats
7 Song Meter SM2BAT Copyright © 2009-2011
to-noise ratio over +36dB gain. (When using +36dB gain, take care to
use the recommended jumper settings. Other permutations may not
provide as good signal quality).
The SMX-US microphone does not need the 2.5V 2.2K bias, but will
work with or without the bias jumper present. Note that the jumper is
required for the SMX-II acoustic microphones.
Schedule
YoucanconfiguretheSong Metertorecordonlyfromsunsettosunrise
each day in half hour segments as follows:
First, configure your latitude, longitude, and UTC offset in the
“Location” settings.
Next, enter the following advanced schedule:
01 AT SSET-00:00:00
02 DO
03 RECORD 00:30:00 (recommended for 384kHz)
or 03 RECORD 01:00:00 (recommended for 192khz)
04 GOTO LINE 03 00X
05 UNTSRIS+00:00:00
06 GOTO LINE 01 00X
The schedule above will wait for sunset, then record back-to-back one-
hour or half-hour segments until sunrise (the last segment will end
early at sunrise), and repeat daily. You can modify this example to suit
your own needs.
Note that the maximum uncompressed file length is 2GB which works
out to 46.6 minutes at 384kHz mono and 192kHz stereo or 93.2
minutes at 192kHz mono. If you use one hour periods instead of half-
hour periods for 384kHz mono or 192kHz stereo, recordings would be
split into alternating 46.6 and 13.4 minute recordings which may be
confusing.
Audio Settings
The audio settings should be set as follows: