A seismic streamer comprising: a first group of hydrophones having outputs combined to produce a first group response; wherein the hydrophones in the first group are disposed at predetermined irregular positions along the length of the seismic streamer; characterized in that: the predetermined irregular positions are specified by a statistically random sequence of numbers, each number defining a unique deviation of the position of an associated one of the hydrophones from a corresponding nominal position in a uniform spacing of hydrophones; and said predetermined irregular positions of the hydrophones along the length of the seismic streamer having been determined by: (a) defining a series of uniformly spaced positions along the length of the seismic streamer, each of the positions associated with one of the hydrophones of the group of hydrophones being positioned along the streamer; (b) assigning each of the statistically random sequence of unique numbers to a corresponding one of the hydrophones of the group of hydrophones; and (c) positioning the hydrophones in the seismic streamer at hydrophone positions longitudinally offset from the series of uniformly spaced positions along the length of the seismic streamer by an amount at each hydrophone position proportional to the corresponding assigned unique numbers. a first group of hydrophones having outputs combined to produce a first group response; wherein the hydrophones in the first group are disposed at predetermined irregular positions along the length of the seismic streamer; characterized in that: the predetermined irregular positions are specified by a statistically random sequence of numbers, each number defining a unique deviation of the position of an associated one of the hydrophones from a corresponding nominal position in a uniform spacing of hydrophones; and said predetermined irregular positions of the hydrophones along the length of the seismic streamer having been determined by: (a) defining a series of uniformly spaced positions along the length of the seismic streamer, each of the positions associated with one of the hydrophones of the group of hydrophones being positioned along the streamer; (b) assigning each of the statistically random sequence of unique numbers to a corresponding one of the hydrophones of the group of hydrophones; and (c) positioning the hydrophones in the seismic streamer at hydrophone positions longitudinally offset from the series of uniformly spaced positions along the length of the seismic streamer by an amount at each hydrophone position proportional to the corresponding assigned unique numbers. the predetermined irregular positions are specified by a statistically random sequence of numbers, each number defining a unique deviation of the position of an associated one of the hydrophones from a corresponding nominal position in a uniform spacing of hydrophones; and said predetermined irregular positions of the hydrophones along the length of the seismic streamer having been determined by: (a) defining a series of uniformly spaced positions along the length of the seismic streamer, each of the positions associated with one of the hydrophones of the group of hydrophones being positioned along the streamer; (b) assigning each of the statistically random sequence of unique numbers to a corresponding one of the hydrophones of the group of hydrophones; and (c) positioning the hydrophones in the seismic streamer at hydrophone positions longitudinally offset from the series of uniformly spaced positions along the length of the seismic streamer by an amount at each hydrophone position proportional to the corresponding assigned unique numbers. (a) defining a series of uniformly spaced positions along the length of the seismic streamer, each of the positions associated with one of the hydrophones of the group of hydrophones being positioned along the streamer; (b) assigning each of the statistically random sequence of unique numbers to a corresponding one of the hydrophones of the group of hydrophones; and (c) positioning the hydrophones in the seismic streamer at hydrophone positions longitudinally offset from the series of uniformly spaced positions along the length of the seismic streamer by an amount at each hydrophone position proportional to the corresponding assigned unique numbers.