User Section


Please visit regularly this section for updates and information to help you operating the AURAL properly.
Specifications are subject to change without notices.

If you have question about the AURAL, please visit our FAQ to see if your question can be answered, or contact us directly.




Update (for board v4R6 and up)


User Guide

User Guide (last update: November 2016)


Remplacement Procedure

Note that any replacement procedure must be done only after recommandation from Multi-Électronique.








FAQ (Frequently asked questions)

This section provides answers to some of the most frequently asked questions about the AURAL. If your questions is not answered here, or you need more information, please get in touch with us.

Questions regarding AURAL Setup and InfoWAV

Questions regarding batteries

Questions regarding the mooring




When should I update my software?

- The latest software update is always available on our website. We recommend visiting regularly this section to make sure you always run the latest version. You must remove old version through the usual uninstalling procedure before installing new one.

Should I use the software from the USB key or those available on the website?

- The software you received with your AURAL are the most up-to-date during that period. But, we recommend visiting regularly the User section to make sure you always run the latest version. You must remove old version through the usual uninstalling procedure before installing new one.

Do AURAL Setup and InfoWAV work with Apple Mac?

- No, AURAL Setup and InfoWav are compatibles with Windows 2000, XP and 7.

Why is the battery life shorter nowadays than formerly?

- In recent years, battery manufacturers' specifications have changed to meet RoHS standards. Battery no longer offers a constant drain of 20,5 Amp/Hrs as before, but now ~15 Amp/Hrs.

Which brand of battery do you recommend?

- We recommend Energizer EN95 alkaline "D" cells. This model performed the best in our lab tests. Duracell and Panasonic are also popular brands used by our customers.

You can also get battery pack (for alternate battery rack) conceived by Multi-Electronique. Click here for more information.

Does cold water affect the lifetime of the battery?

- Tests performed so far show that a water temperature of ± 0 °C (32 °F) has no significant impact on the battery lifetime.

Why is it important to verify the batteries even if they are new?

- Before inserting new batteries in a AURAL (with conventional battery rack), you must verify each of them with a battery tester. Even if they come directly from the manufacturer, it is possible to come across a dead battery. Batteries in the AURAL are connected in series. One defective battery can affect an entire string. You risk therefore losing weeks or months of recording due to a single defective cell.

This recommendation is for conventional battery rack only. Battery packs made by Multi-Electronique have been tested and are ready to use.

At what maximum depth can my AURAL be deployed?

- The tested depth is 300 meters (984 ft).

Can I use old anodes for a second deployment?

- We recommend using new anodes after each deployment. Anodes sustainability depends on several factors:

These hostile conditions accelerate corrosion and the anodes are designed to further protect better the stainless steel components.

What is the maximum sampling rate?

- The maximum sampling rate is 32768 Hz.

What is the maximum size of hard disk memory available?

- AURAL memory hard drives depend on the trend and market availability. Nowadays, the maximum size of hard drive with PATA (Parallel AT Attachment) interface is 320 GB. You can get a double hard drive adaptation kit to double the memory of your AURAL (640GB).

Which firmware version is in my AURAL?

- Recent AURALs have firmware V4.1.3.

The latest firmware for AURAL running with older Printed Circuit Board V3 is V3.4.0

Why am I not able to communicate with my AURAL in configuration mode?

- It may be in standby mode. Since the AURAL is designed for energy saving, it will get into standby mode after 5 minutes of inactivity in configuration mode. To wake it, hold the SETUP button of the control box and press the RESET button. You must hold the SETUP until the message "Entering in setup" appears in the AURAL Setup message box. You will be able to continue configuration using AURAL Setup.

Which configuration should I program my AURAL?

- It depends on many factors: the number of battery, the sampling rate, the hard drive memory, the size of the WAV files, etc.

There is no better configuration. We recommend that you base yourself on the information that you already know, and try several combinations in AURAL Setup. By pressing "Compute", the software estimate the battery and recording lifetime corresponding to your criterias.

Notice also that a very large wav file may take a long time to open later.

What is the sonar equation?

- 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). The 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

* In practice there is a self noise of a bew bits that should be considered.

Note that the receiving sensitivity varies with frequency. The (RS vs. frequency) curve is obtained by users from their calibration according to ANSI calibration standards. Hydrophone RS nominal value is provided by HTI manufacturer. The (RS vs. frequency) curve measured by users is relatively flat (± 1 dB), in the low frequency band below 5-10 kHz.