Apparatus for guided wave testing a test object comprising: a linear array of receiver electromagnetic acoustic transducers, each of said receiver electromagnetic acoustic transducers having a receiver coil and serving to convert vibrations in said test object into received electrical signals in said receiver coil; and at least one linear array of transmitter electromagnetic acoustic transducers disposed substantially parallel to said linear array of receiver electromagnetic acoustic transducers and configured to launch guided waves in said test object in a direction substantially perpendicular to said at least one linear array of transmitter electromagnetic acoustic transducers, each of said transmitter electromagnetic acoustic transducers having a transmitter coil and serving to convert driving electrical signals in said transmitter coil into vibrations in said test object; wherein one of: (i) transmitter coils of electromagnetic acoustic transducers within said at least one linear array of transmitter electromagnetic acoustic transducers have a common winding direction, receiver coils of adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers have alternating winding directions, and receiver coils of at least two adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers are connected in series; and (ii) transmitter coils of electromagnetic acoustic transducers within said at least one linear array of transmitter electromagnetic acoustic transducers have alternating winding directions, receiver coils of adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers have a common winding direction and receiver coils of at least two adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers are connected in series. a linear array of receiver electromagnetic acoustic transducers, each of said receiver electromagnetic acoustic transducers having a receiver coil and serving to convert vibrations in said test object into received electrical signals in said receiver coil; and at least one linear array of transmitter electromagnetic acoustic transducers disposed substantially parallel to said linear array of receiver electromagnetic acoustic transducers and configured to launch guided waves in said test object in a direction substantially perpendicular to said at least one linear array of transmitter electromagnetic acoustic transducers, each of said transmitter electromagnetic acoustic transducers having a transmitter coil and serving to convert driving electrical signals in said transmitter coil into vibrations in said test object; wherein one of: (i) transmitter coils of electromagnetic acoustic transducers within said at least one linear array of transmitter electromagnetic acoustic transducers have a common winding direction, receiver coils of adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers have alternating winding directions, and receiver coils of at least two adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers are connected in series; and (ii) transmitter coils of electromagnetic acoustic transducers within said at least one linear array of transmitter electromagnetic acoustic transducers have alternating winding directions, receiver coils of adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers have a common winding direction and receiver coils of at least two adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers are connected in series. (i) transmitter coils of electromagnetic acoustic transducers within said at least one linear array of transmitter electromagnetic acoustic transducers have a common winding direction, receiver coils of adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers have alternating winding directions, and receiver coils of at least two adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers are connected in series; and (ii) transmitter coils of electromagnetic acoustic transducers within said at least one linear array of transmitter electromagnetic acoustic transducers have alternating winding directions, receiver coils of adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers have a common winding direction and receiver coils of at least two adjacent electromagnetic acoustic transducers within said linear array of receiver electromagnetic acoustic transducers are connected in series.