Complex sentence: Lennon's post-Beatles albums frequently employed doubling echo on his vocals, in place of the ADT system the Beatles had; some critics complained that the effect made the impression that Lennon recorded all his vocals in a bathroom.
Split into simpler sentences: Lennon's post-Beatles albums frequently employed doubling echo on his vocals in place of the ADT. Some critics complained that the effect gave the impression that Lennon recorded all his vocals in a bathroom.