Song Meter SM4M User Guide Supplement
1 Overview
Wildlife Acoustics, Inc.
page
3
1.5
Hydrophone Options
Three hydrophone options are available for the SM4M: Acoustic, Ultrasonic, and
High-SPL.
The
Acoustic Hydrophone
is used to record whale songs, dolphin whistles,
and/or ambient noise levels, from infrasonic into ultrasonic frequencies.
The
Ultrasonic Hydrophone
increases the recording bandwidth of the system
to allow recordings not only from ultrasonic dolphin and porpoise echolocation
calls, but also ultrasonic anthropogenic sounds as well.
NOTE:
For low noise applications, choose the Acoustic Model. The Ultrasonic has a
higher noise floor which can mask quieter noises. See the Specifications section for
more information.
The
High-SPL Hydrophone
is specifically tailored to recording and quantifying
high sound pressure levels such as those produced by pile drivers and air guns.
When combined with any of the other hydrophones in a dual hydrophone
configuration, the unit can record quiet or distant sounds from any source
including marine life with one hydrophone, and at the same time accurately
record and quantify very loud sounds from anthropogenic sources with the
High-SPL.
The sensitivity of each hydrophone is calibrated to a 0.1 dB resolution by the
hydrophone manufacturer. This value appears on a tag attached to the
hydrophone cable and is reported as the average value over the band from 200
Hz to 1.6 kHz in increments of 100 Hz.
Hydrophone Recording Bandwidth and Dynamic Range
Hydrophones
± 5 dB Recording
Bandwidth (Hz)
Dynamic Range (db
SPL)
Standard Acoustic
2 – 48,000
78 – 165
Ultrasonic
2 – 192,000
81 – 165
High-SPL
2 – 48,000
150 – 240
1.6
SM4M Visual Tour
The housing contains a large board with electronics and batteries that slides free
of the enclosure for servicing. The
Deep Water
model also contains a second
board that is attached to the first to hold additional batteries.
WARNING
: Do not allow water, moisture, dirt, or debris of any kind to come in contact
with the internal parts of your recorder.
