
W561XXX DESIGN GUIDE
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are many combinations of timbre size, sampling rate, and the dT of playing back. The following
tables are examples.
Timbre size = 1024 samples
Head length = 760 samples
sampling rate in
recording
recording time
sample rate for
playing back
dT for
playing back
track notation
12544 Hz
60.6 ms
1.0
G3
6272 Hz
121.1 ms
12544
sample/sec
0.5
G2
3136 Hz
242.3 ms
0.25
G1
8232 Hz
92.3 ms
0.65625
C3
Timbre size = 4096 samples
Head length = 3064 samples
sampling rate in
recording
recording time
sample rate for
playing back
dT for
playing back
track notation
12544 Hz
244.3 ms
1.0
G3
6272 Hz
488.5 ms
12544
sample/sec
0.5
G2
3136 Hz
977.0 ms
0.25
G1
5684 Hz
539.1 ms
0.453125
F2
Percussive Track Modification
should be some midi tracks, named percussive tracks, utilizing the percussive timbres. The
percussive tracks have one difference from the musical tracks. There are many notes with
different pitches in the musical tracks while the percussive tracks is usually composed of the
notes with a specific pitch which is decided by the recording sampling rate of the percussive
timbre. Besides, the original midi file usually combines all the notes of all percussive instruments
in one or two tracks rather than separate different percussive instruments into different tracks, so
users should make some modifications to them.
The steps for modifying the percussive tracks of a midi file are:
(I) Find the percussive track of the midi file, and split it's notes into different tracks by pitches.
This procedure can separate different percussive instruments into different tracks.
(II) For the hardware limitation (I), user should decide how many channel resources the
percussive tracks can share. For example, maybe they can share the 2 of 4 channels.
(III) Deleted unimportant percussive tracks and notes and make sure that no more than 2 notes
(the share amount of channels) are played at the same time.
(IV) Assign the timbre index of each track.
In fact, the timbre for percussive sound can be treated as a normal timbre, so there