15 kHz was the sample limit.

You know, someone could simply WRITE one. It doesn't have to be integrated into the player software

How do you propose to automate it, then? The idea was that the player samples it's own output and sets up an EQ setting that's compensated to give a flat 0 - 15 kHz response, which you can then use as a basis to adjust to your hearing preferences.

One of the few remaining Mk1 owners... #00015