YMF795 Datasheet, PDF (12/45 Pages) YAMAHA CORPORATION – APL-2 Automobile sound Player-2

YMF795
■ Caution ■
When KEY is turned on again while release rate is not completely finished yet in the same channel, timbre may
change.
This happens in both sustained sound and decaying sound.
The reason why it happens is that both envelope and phase in the career side and modulator side of the FM sound
source deviate.
The hardware creating the phase and envelope of FM sound source starts its operation according to the following
two conditions.
- End of the release rate.
- Occurrence of Key ON.
Timbre data is created on the assumption that modulator, phase between careers, and envelope operate at the same
timing; therefore, timbre may vary when this condition is not met.
Description mentioned above is explained with the envelope waveform.
For example, assume that a timbre of which only release time differs between carrier and modulator is present. If
operation is in the state completely stopped, it shifts to the Attack rate in conjunction with KEY ON. If the
previous sound generation is being released and is not in a state completely stopped, the release settings is forcibly
hastened (8.94 ms) and a stopped state is shifted to the attack rate state. (Dotted line of A)
Although envelope indicated in a solid line changes to the attack rate state soon at the second KEY ON, shifting
to the attack rate state is not immediately performed because sound indicated in a dotted line is not completely
stopped. The release time is hastened to stop the state, and then the state stopped is shifted to the attack rate state.
The starting time deviation of both envelopes and phase caused by this deviation causes a change of timbre.
Timbre varies.
A
TK
TK
TI
How to avoid this symptom:
Be sure to observe “Try to pronounce under the condition that the release is completely stopped.”
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