Music Studio - ZX Spectrum beeper music engine
Original Z80 code by Sasa Pusica, 1988
1tracker version by Shiru 01'2018, based on Beepola version by ccowley


Code comes from a ZX Spectrum music editor with the same name, The Music 
Studio. 

The engine features two tone channels. First channel can also play a 
simple slide drum in a range of pitches, starting from B-5. Global speed 
(1..99). 

Use a note B-5 and above in the first channel to play a drum sound. 


T1 d T2 d
.... ....
|  | |  |
+ch1 +ch2

T1,T2 : Tone channels
 Tn : Note, B-2..B-7
  d : Detune, 1..9
