Digital Reverb The PCM 81 takes where the PCM 80 left off, and adds AES/EBU Digital I/O, includes algorithms and presets from the Pitch FX and Vocal Fix Cards, and adds 24-bit converters for even higher quality audio. The PCM 81 maintains Lexicon's highest standards for sonic clarity, and its extraordinary processing power yields the finest effects available in its price class, plus outstanding reverberation.