Hi It is possible to transpose my mp3 and midi files in C Major and What will be the procedure thanks in advance

What kinde of question is this? Cos is paseble!On Ketron instruments everything is pasable,but here is a little trouble.
If you transpose Mp3 file,on every transpose step sound on every step is worse and worse....On the end of transpose sound is like a frog saund....
For Midi file is no problem.Simply hit a button for transpose...

Thanks Dusan I will follow your advise

WAV files work better as they are uncompressed. you can also adjust speed without affecting pitch