Huby - ZX Spectrum 1-bit music engine by Shiru (shiru@mail.ru)
Original Z80 code 04'11, 1tracker engine 04.12
Public Domain


A very simple and limited enigine. It has two tone channels without 
volume and loop support, but with detune, global speed, one drum sound. 
Main feature of the engine is its very small size, just 100 bytes of 
code, along with compact data format. It could be useful for music games 
with a tight memory budget. 

Each channel has two columns. They are note of the channel and detune 
value that is only applied to a note on the same row. Last column is a 
drum, non-zero value triggers the drum. When it plays, it replaces note 
on the first channel. 

Detune could be used to produce 'fat' sounds by putting the same note on 
both channels, and using detune on one of them. 

Notes aren't continuous, they only play for a row. To make a longer note 
just repeat it as much as needed. 


The columns are:

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

T1,T2 : Tone channels
 Tn : Note, A#1..B-7
  d : Detune, 1..9
  
 D : Drum
