Pragmatics of a polyphonic calculator (chapter 2)

[Joseph_21sv]

Ever since fully programmable monophonic sound came to handheld calculators in the form of the User RPL BEEP command with 12-digit floating point frequency control, there has been technical thought that it could be nice for a calculator to have polyphonic sound. After all, they all reasoned, it could only be logical that a polyphonic calculator should materialize. However, that failed to happen because no major manufacturer thought that that could be done profitably without crippling the calculator's numerical functionality very much. How correct that might ever have been is up for debate, but this is not the thread for that debate. Rather, it is a thread for discussing exactly what specifications a polyphonic calculator would need to have to be taken as at least a semi-amateur grade instrument.
Anyway, here is my list of minimum requirements for that standard:
CPU data bus/data register width: 8 bits
CPU base clock rate: 894.886 kHz
Hardware sound mixer (if used): Monaural Triphonic with at least one user-assignable voice
Display resolution: equivalent to 160x88
Display master palette: 8 colors (preferably 3-bit RGB)
Calculator type and level: Entry level Scientific/Business programmable
Floating point display precision: 10 digits
Programming model: partially merged keystroke
Program flow control: branching, conditional transfers
Storage memory on board: 64K
Do you agree that this, by post-HP 28C standards, makes a passable semi-amateur grade instrument?