An ultrasonic diagnostic imaging system produces an image with an extended focal range and reduced speckle by transmitting a plurality of beams spaced along an array for multiline reception. The receive multilines of a plurality of transmit beams are spatially aligned with phase adjustment between the respective receive multilines to effect signal alignment, detected and combined. The combined multilines produce the effect of an extended transmit focus so that an image produced using the combined multilines exhibits an extended focal range. Speckle is reduced by nonlinearly combining received multilines produced by different transmit apertures.