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Hardware and Software for Investigating
Animal Acoustic Communication
Avisoft Bioacoustics
Schönfließer Str. 83
16548 Glienicke

tel +49 33056 426086
fax +49 33056 426087




Animal Sounds

Accessories for Connecting Hydrophones to the Avisoft-Bioacoustics UltraSoundGate Devices

The UltraSoundGate system allows to connect various hydrophones. Generally, the commercially available hydrophones can be divided into two basic categories :
  • Plain hydrophones that consist of the piezo electric sensor element only (the nominal capacitance is usually in the range between 1 ... 10 nF)
  • Hydrophones with integrated pre-amplifier that additionally require an external supply voltage between 5 and 32V (depending on the specific model)
Each of these hydrophone types have different operating requirements. The hydrophones without pre-amplifier require an external high-impedance pre-amplifier, while the hydrophones with integrated amplifier have a low-impedance output and require a DC supply voltage. Therefore, the hydrophone input of the recording device must be compatible to the specific hydrophone type. Especially for recording high frequency vocalizations or ultrasonic echolocation clicks by dolphins, high-intensity and low-frequency ambient noise might be a problem. A suited analog high-pass filter can help to prevent clipping caused by loud low-frequency noise. For that reason, a high-pass filter with adjustable cutoff frequency is desired. The two dedicated UltraSoundGate hydrophone interface boxes meet these requirements.
Principle of the UltraSoundGate hydrophone recording system
Principle of the UltraSoundGate hydrophone recording system (larger view)

UltraSoundGate Hi-Pass Filter and Hydrophone Power Supply Adapter

for hydrophones with integrated pre-amplifier
part # 42001
UltraSoundGate Hi-Pass
  • Hydrophone input connector : 3-pole screw clamp inside the housing. *
  • Selectable hi-pass cut-off frequencies [Hz] : 10, 25, 50, 100, 250, 500, 1k, 2.5k, 5k, 10k, 25k, 50kHz
  • Selectable hydrophone power supply voltage : 5V (supplied internally from the UltraSoundGate 116/416) or external (via 2.1 mm coaxial connector)
  • Splash-proof and electromagnetically shielding aluminium housing
  • Physical dimensions : 60 (110) x 55 x 30 mm
  • Weight : 150 g

* In order to simplify the exchange of hydrophones, an adapter cable with a female splash-proof XLR-3 connector is also supplied. The corresponding male XLR connector for the hydrophone is included too.

In case the hydrophone can be operated from a 5V DC voltage (e.g. the Cetacean Research Technology C304), then there is no additional external power supply required. Hydrophones requiring voltages of more than 5V (e.g. Reson TC4032) can be powered from an externally supplied voltage (e.g. a battery).

UltraSoundGate Charge Amplifier with Hi-Pass Filter

for hydrophones without integrated pre-amplifier
part # 42002 (USG)
part # 42003 (P48)
UltraSoundGate Charge Amplifier
  • Hydrophone input connector : female BNC socket
  • Selectable input resistance : 3.3kOhm ... 15MOhm
  • Selectable input capacitance : 100pF or 1nF
  • Available hi-pass cut-off frequencies at an input capacitance of 1nF [Hz] : 10, 25, 50, 100, 250, 500, 1k, 2.5k, 5k, 10k, 25k, 50kHz (or 100 Hz ... 500 kHz at 100 pF)
  • Gain = 20 log (capacitance of the hydrophone / selected input capacitance)
  • Splash-proof and electromagnetically shielding aluminium housing
  • Physical dimensions : 60 (110) x 55 x 30 mm
  • Weight : 150 g
The gain of the charge amplifier depends both on the nominal capacitance of the connected hydrophone and the selected amplifier input capacitance. A hydrophone capacitance of 3nF and an input capacitance of 1nF would provide a gain of approximately 10 dB. The alternate input capacitance of 100pF would provide a gain of 30 dB. The supply voltage for the amplifier is provided by the UltraSoundGate device (via USB) which means that there is no additional power supply required. A special phantom powered version allows to connect the amplifier directly to other audio recording equipment.
UltraSoundGate Charge Amplifier with RESON TC 4013
A RESON TC 4013 hydrophone connected to the USG charge amplifier.
CRT C304 + Hi-Pass + USG

A complete hydrophone recording system consisting of a CRT C304 hydrophone, an UltraSoundGate Hi-Pass filter and an UltraSoundGate 116.

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© 2005 Avisoft Bioacoustics

last modified on 12 November 2004