To specify intelligently an unambiguous tow-noise level in marine seismic exploration, the electroacoustic characteristics of the streamer must be understood. In this paper, these characteristics are examined as a basis for an industry-wide standard for specifying streamer tow-noise level.Sources of tow noise--including electrical, ambient, flow, radiated, and mechanically induced--are examined and the important parameters that control their amplitude spectrum are presented. The theoretical bases for various means of reducing the components of tow noise are analyzed and compared with experimental results.With this background of tow-noise sources and noise-reduction schemes, the noise signal is traced from the hydrophone/seawater interface to the recording system. The hydrophone array's amplitude response and phase response are determined from the transfer characteristics of the coupling circuit and the recording system.Finally, a method for specifying tow-noise level is proposed. The specified tow-noise level is referenced to the hydrophone input terminals and is monitored at the output of the recording system. Therefore, the standard requires that the important electroacoustic characteristics outlined in this paper be specified.