What is Dolby HX-Pro?
HX-Pro is a scheme to reduce the level of the bias signal when high frequency information is present in the recorded signal. Sufficient high frequency information will act to bias the tape itself, and by reducing the AC bias signal somewhat, additional signal can be applied without saturating the tape. This is a single-ended system; it requires no decoding on playback, because it merely permits more signal to be recorded on the tape. In theory it is an excellent idea, and some implementations have lived up to the promise of the method, although some other implementations have produced unpleasant artifacts.
HX-Pro is a scheme to reduce the level of the bias signal when high frequency information is present in the recorded signal. Sufficient high frequency information will act to bias the tape itself, and by reducing the AC bias signal somewhat, additional signal can be applied without saturating the tape. This is a single-ended system; it requires no decoding on playback, because it merely permits more signal to be recorded on the tape. In theory it is an excellent idea, and some implementations have lived up to the promise of the method, although some other implementations have produced unpleasant artifacts.