BENTHOWAVE INSTRUMENT INC. Acoustic Transducer & System
Low Noise, Low Power, and Low Frequency Hydrophone
BII7120 Series Low Noise, Low Power, and Low Frequency Hydrophone: Noise Level below Sea State Zero
BII's low noise hydrophones are optimized to possess self noise levels below sea-state zero with omnidirectional response in low frequency range and toroidal response in high frequency range. Its streamlined hemispherical dome minimizes drag force and hydrodynamic noise. The power consumption can be customized to be 600µA quiescent current at 5VDC for battery powered underwater instrumentation. A spatial array of multiple hydrophones can be set up for directional measurement system. BII7128 hydrophones can measure underwater sounds and pressure fluctuations down to 0.1Hz infrasonic sounds: Surface Waves (Wave-height Sensor), Turbulences, seismic, ocean traffics, industrial noises, precipitations, biologics, ... With these low power hydrophones, battery and system lifetimes are extended, and lighter portable systems with lower-capacity batteries can be achieved. Its compact small size avoids interferences to acoustic field under test. Preamplifiers integrated in hydrophones can drive cable up to 200m without signal loss. Available cable terminals include audio connectors (TRS, XLR, DIN), BNC, and underwater mateable connectors. The housing and mounting part are corrosion resistant plastics and/or stainless steels.
Low Frequency Sounds in the Ocean at 1 Hz to 1 kHz. Low Frequency Sounds between 1Hz to 1kHz undergo little attenuation in ocean and lakes: 1.2x10-7 at 1Hz, 0.0002 at 10Hz, 0.0015 at 100Hz, 0.07 at 1kHz, in dB/km, proximately. The major propagation losses are Spreading Loss, Absorption and Scattering at boundaries such as seafloor sediments. The sounds being trapped in deep sound channel or SOFAR channel avoiding losses from both top and bottom boundaries can propagate very big area with very low loss. These low frequency sounds contain valuable information on their sources and propagation areas such as Weathers (Winds, Rains, Surface Waves, Ice, Storms, …), Geological Process (Earthquakes, Tsunamis, Moving of Tectonic Plates and Crusts,…), Marine Animals (Whales, Dolphins, Fish, Invertebrates, …), Anthropogenic Activities (Shipping, Harbor, Oil and Wind Energy Extraction, Air Guns, …). Besides sounds detection or monitoring with deployment at 1000m depth, the distributed hydrophone network in shallow water (at a specific depth) can also be used to detect and monitor upward sounds being refracted from SOFAR channel.
| Typical Applications | |
| Noise Measurement, Marine Bioacoustics. |
Surface Waves, Ocean Turbulences, Marine
Hydrodynamics, Marine Geophysics. |
| Passive Acoustic Monitoring (PAM System). | Battery-Powered Instruments: Sonobuoy, Recorder, Transponder, Acoustic Release... |
| Wave-height Sensor, Wave/Tide Recorder/Logger. | Coastal/Offshore Processes, Engineering & Management, Wave-Structure Interaction. |
| Related Products | |
| BII7010 Low Noise Broadband Hydrophone | BII7070 Low Noise Directional Hydrophone |
| Acoustic Transducers and Measurement Systems: Installation/Mounting, Ordering, Wiring, Array & Aperture Design and much more. |
| Low Noise, Low Power, and Low Frequency Hydrophones. |
| Hydrophone | Noise Density @ 10kHz | Frequency Range | Directional Response Pattern | Maximum Depth |
| BII7121 Series | 20 dB μPa/√Hz | 1.0Hz to 50kHz | Omnidirectional to Toroidal | 300 m |
| BII7122 Series | 20 dB μPa/√Hz | 2.0Hz to 70kHz | Omnidirectional to Toroidal | 300 m |
| BII7123 Series | 32 dB μPa/√Hz | 2.0Hz to 120kHz | Omnidirectional to Toroidal | 300 m |
| BII7125 Series | 31 dB μPa/√Hz | 3.0Hz to 180kHz | Omnidirectional to Toroidal | 300 m |
| BII7126 Series | 30 dB μPa/√Hz | 10Hz to 260kHz | Omnidirectional to Toroidal | 300 m |
| BII7128 Series | 30 dB μPa/√Hz | 0.05Hz to 30/40kHz | Omnidirectional to Toroidal | 150/350 m |
| BII7079 Series | 20 dB μPa/√Hz | 3.0Hz to 100kHz | Conical (Planar Receiving Face) | 300 m |