HX-Pro is a system to automatically adjust the bias level when recording, in order to increase headroom. It is only needed on the recording device, and improves

HX-Pro is a system to automatically adjust the bias level when recording, in order to increase headroom. It is only needed on the recording device, and improves playback quality on all tape decks. Dolby B/C/S is needed on both the recording and playback decks, as it changes the frequency response to boost high-frequency sound quality.