A memory card player, designed to reproduce a variety of digital audio data files from a memory card, is disclosed. It also includes a first reader configured to read card information from cards a first time and a second reader configured to read card information from cards a second time. For each intermediate beamlet, the associated piston error contribution is recovered using a Hadamard decoder. After a first zone is shocked, the tool assembly can be moved to a new zone, or multiple shocks can be applied cyclically at the selected zone.