Some CDs were mastered to have pre-emphasis that boosted high frequencies if the player didn't properly account for it. This caused them to sound "high pitched"

Some CDs were mastered to have pre-emphasis that boosted high frequencies if the player didn't properly account for it. This caused them to sound "high pitched". https://wiki.hydrogenaud.io/index.php?title=Pre-emphasis https://wiki.hydrogenaud.io/index.php?title=Pre-emphasis