There has been much discussion on some web fora about the differences between different brands’ cassette equalization standards.
As I stated here in 2006, there is a 4 dB ambiguity at 16 kHz.
Many things conspire to make this 4 dB ambiguity essentially meaningless in a generally low-fi medium. The only reason I’m mentioning this now is that I’ve been bombarded with email from more than one participant in this discussion and apparently there may be some editorial judgment attached to what is posted.
Jay McKnight has graciously permitted my posting of his comments to me: