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Specification sheet

User Guide

360° view*


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Main purposes

The AURAL-M2 ( Autonomous Underwater Recorder for Acoustic Listening) is an underwater recorder used for any application that requires continuous underwater sound recording:

- Marine mammals
- Methane bubble
- Ice cracking
- Boats
- Underwater noise pollution
- ...


- Underwater sound recorder
- Pressure sensor (0 to 1000 psi) (device depth)
- Temperature sensor (-10°C to 40°C) (14°F to 104°F)


- Duration: can be deployed up to one year (depending on setting parameters)
- 16 Bits digital recording
- Programmable recording mode: continuous with pause, delay start time spaced recording
- Configurable sampling rate: 256 Hz to 32 768 Hz
- Usable frequency range: 10 Hz to 16 384 Hz
- Adjustable amplifier: 16, 18, 20 and 22 DB
- Hard drive storage using WAV file formatTCXO time base for stability
- Low power Logic and CPU
- Programming through RS232 (38,Kbs, N, 8, 1)
- FAT32 Support (hard drive)
- WAV Support (files)
- 2 Softwares included: AURAL Setup for device setting and InfoWAV to extract informations included in the WAV files' headers
- Three (3) sizes available: 16-batteries, 64-batteries and 128-batteries

Receiving sensitivity

The sonar equation is : SPL(dB re 1µPa) = Vdet – RS – G

SPL: Sound pressure level detected by the AURAL (µPa)
Vdet: Acoustic signal detected by the hydrophone in dB, therefore 20 log (signal in volt). AURAL measures over a range of ± 2V, converted to 16 bit
RS: Receiving sensitivity ( ~165 dBV / µPa, (see HTI specification))
G: AURAL gain (16, 18, 20 or 22 dB)

Gain (dB)
Saturation SPL
Vdet = 2V
(dB re 1 µPa)
* Minimum recorder SPL at
Vdet = 1 bit = ±1/(2^15)) * 2V
(dB re 1µPa)
Difference (dB)
16 155 65 90
18 153 63 90
20 151 61 90
22 149 59 90


Take note that Multi-Électronique is not specialised in the mooring of oceanographic instrument. Deploying an instrument is very technical and requires a lot of knowledge. It is why the help of competent engineer is highly recommended. Here is some information to help you. Different methods can be used to immerse an AURAL-M2 underwater. The surrounding where the unit will be based must be exempt of any harmful noise. The following example is a mooring that has already been made by many customers.

Customers recordings


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