C304 & C304XR Hydrophones

Cetacean Research C304 series of hydrophones has been replaced by the C305 series. The C305 replaces the C304XR and the C305X replaces the C304.

Cetacean Research™ 305 hydrophone

The following is retained for reference.

The Cetacean Research C304 and C304XR hydrophones have a directional receive pattern with very wide frequency response for monitoring ultrasonic signals not detectable by competing brands. The connector is an integral part of the hydrophone. The hydrophones are not individually calibrated but calibrated frequency response measurements can be performed on request.

  • Cetacean Research™ C304 hydrophone
  • Cetacean Research™ C304 hydrophone
  • Cetacean Research™ C57 hydrophone with hydrophone protection cage
  • Cetacean Research™ C304 frequency response
  • Cetacean Research™C304 beam pattern

C304 hydrophone specifications

C304 C304XR
Linear Frequency Range (±3dB) [kHz] 0.012 to 250+ 0.012 to 1000
Usable Frequency Range (+3/-12dB) [kHz] 0.005 to 250+ 0.005 to 2000+
Transducer Sensitivity* [dB, re 1V/µPa] -201 -201
Preamplifier Gain [db] 33 20
Effective Sensitivity* [dB, re 1V/µPa] -168 -181
SPL Equiv. Self Noise at 1kHz [dB, re 1µPa/√Hz] ≈ 63 ≈ 63
Power Requirement [Vdc] 5 to 32 5 to 32
RMS Overload Acoustic Pressure [dB, re 1µPa] 172 to 189 185 to 202
Maximum Operating Depth ** [m] 460 460
Operating Temperature Range [°C] -40 to 60 -40 to 60
Output Impedance [Ω] 10 10
Dimensions [mm] 83 L x 32 W x (25 to 6)T 83 L x 32 W x (25 to 6)T
Integral Connector **** Subconn MCBH3MSS Subconn MCBH3MSS

*  Transducer Sensitivity + Preamplifier Gain = Effective Sensitivity.
**  1,000 meter versions are available. Append "-1k" to the model number to order a hydrophone with a depth rating >1,000 meters.
*** Connectors are rated to a depth of 7,000 meters; see below (or to the side) for mating connector and cables.

Shielded Cable Length [m]

  • mating connector molded to 15, 30, or 50 [m] shielded cable
  • other lengths available on a custom order basis
  • cable includes Integral Connector rated to a depth of 7,000 meters.


  • omnidirectional below 10kHz;
  • very directional at high frequencies (e.g., ~15º solid angle at 200 kHz, –3dB);
  • directionality pattern is a dipole.

Battery / Connector box

Battery boxes are rated NEMA-4X water resistant. Standard signal connection for Cetacean Research C304 hydrophones is through a watertight female BNC connector with gold center contact. The hydrophones are powered by one 9V battery (not included) or an optional long-life rechargeable, external power supply.

Signal Output Female BNC connector
Battery Life [hours] > 20
Box Dimensions [mm] 98 long x 64 wide x 40 high