Tritone v2 - ZX Spectrum beeper music engine
Original Z80 code by Shiru 03'2011, released as Public Domain
1tracker version by Shiru 03'2018

Tritone Digi - ZX Spectrum beeper music engine
Engine and 1tracker version by Shiru 03'2018


Original Tritone engine features three channels of tone with duty cycle 
control and detune support, a set of predefined interrupting clicky 
drums, global speed. 

There is two options on volume mixing that can be changed in the 
Instrument editor tab (F4). In 'Equal' mode all three channels will have 
equal volume. 'Different' mode makes each channel slightly louder than 
previous one, which is useful to create echoes and other effects. Unlike 
most engines, duty cycle and volume are unrelated here, different volume 
does not affect the timbre. 

Tritone Digi is just like the original, with a little better sound 
quality, customizeable interrupting sampled drums support, and per-row 
speed. Three channels of tone with duty cycle control. Unlike the 
original, it always uses unequal volume ratio. 


The columns are:

   T1 dW T2 dW T3 dW Dr
   ..... ..... ..... ..
   |   | |   | |   | 
   +ch1+ +ch2+ +ch3+

Sp T1 dW T2 dW T3 dW D
.. ..... ..... ..... .
   |   | |   | |   | 
   +ch1+ +ch2+ +ch3+
  
Sp : Speed (Tritone Digi only), 1..31

T1,T2,T3: Tone channels, have uniform capabilities
 Tn : Note, C-0..B-7
  d : Detune, 1..9
  W : Duty cycle, 1..8 (1 is 50% square wave, 8 is thin narrow pulse sound)
  
 Dr : Clicky drum (original Tritone only), 1..24
 
  D : Sample drum, 1..7
