Paulwp, your dismissive comments reveal much more about the author than the system. No speaker on earth will reproduce a 50 hertz tone as 60 hertz. A 50 hertz tone will always be reproduced at 50 hertz with distortion components occuring at multiples of that tone, i.e. second harmonic distortion components will be found at 100HZ, but not 60HZ as you have so wrongly suggested. You know even less about physics than sound reproduction.
Marty