Someone just before said that bias has no application during playback and is only applied during record. But if that's the case why does my sony walkman have a switch for "normal" and "CRo2" tapes? Is it necessary to play chromium dioxide tapes on a deck with a chromium dioxide setting?
I thought I answered this post. It is not "necessary" to play chromium dioxide tapes on a deck with such a setting, but failing to do so will result in a boost to high frequency output and an overall sonic difference. You can play any standard cassette on any standard cassette player.