Engineering Solutions to Noise and Vibration Problems

Sound-Guard is a PC-based data acquisition system used to measure, monitor, and log the underwater sound levels from any vessel. It is especially useful for research vessels which need to maintain low radiated noise during sensitive scientific operations. Sound-Guard is designed to be used with existing hull mounted hydrophones. However, existing ships without self noise hydrophones, can use Sound-Guard by installing hull-mounted accelerometers.

Sound-Guard will continuously check compliance of a vessel to an underwater sound criterion. The software will display and compare the measured underwater sound to any specified noise limit including the limit specified by the International Council for the Exploration of the Seas in the Cooperative Research Report 209 (ICES CRR 209).

The Sound-Guard system consists of an industrial-grade rack-mountable PC and touch screen. All Sound-Guard software features can be operated from the touch screen without the need for a mouse or keyboard. Administrative functions (setting up limits, recalling data) require a keyboard and other software applications such as Notepad and/or Excel. Data acquisition is through a 6-channel PCI-card. The hydrophones and accelerometers are not supplied with the Sound-Guard System. For best results and to compare data to known standards like ICES, a one time calibration of underwater noise-to-self noise must be performed.

Sound-Guard software features include:

Technical Specifications

Number Channels: 4 Maximum
Frequency Resolution: 1/3 octave band
Frequency Response: 10 to 50,000 Hertz
Underwater Noise Sensitivity: Vessel dependent

Screen Shots

Sound-Guard Main Data Acquisition Screen
(click to enlarge)

Sound-Guard Parameters Setup Screen
(click to enlarge)

Sound-Guard is a commercially available software package. For more information contact NCE at