Appendix Q & A - Yamaha PLG100-VL Bedienungsanleitung

Appendix : Q & A
1
Some voices sound as if they are in the original octave even when shifted
down an octave.
This is because Virtual Acoustic synthesis accurately simulates the acoustic behaviour of a
pipe or string. Simply stated, the harmonic balance of the voice when played in the normal
octave is retained even when the voice is shifted down an octave. The change in timbre can
be greater or less, depending on the selected voice.
2
Portamento doesn't produce smooth effect on some voices.
Trumpets and some other brass instruments tend to exhibit this phenomenon more than oth-
ers. In a VA tone generator portamento is produced by lengthening or shortening the
instrument's pipe. A trumpet is designed to emphasize the "modes" of the pipe(s) to produce
notes over a wide range using only three valves. When portamento is applied to a trumpet
voice, the pitch tends to jump from mode to mode, thus producing the observed glissando
effect. The same effect occurs with some flute voices. Saxophone modes are not nearly as
strong as trumpet modes, but some sax voices do have two definite modes which, when
spanned by a portamento slide, can produce irregularities.
3
The filter, EG, and other parameters have more effect on some voices than
others.
Most voices use the low-pass filter type, but some use the bandpass or high-pass type. Some
voices use very little filter processing at all. Changing the filter settings may not produce a
particularly noticeable effect. Also the Breath Noise, Throat Formant, Growl, Harmonic En-
hancer and Pitch EG parameter settings cannot have a significant effect on some voices.
4
Some bowed string instrument voices tend to "squeak."
As anyone who has played (or tried to play) a real violin knows, these instruments naturally
tend to squeak if not properly controlled. The same occurs with VA synthesis. As with a real
bowed string instrument, bow speed and pressure must be properly controlled to produce the
desired sound. Bow speed is usually controlled either via breath control or an expression
pedal. Bow pressure is controlled via control number 13: "64" is medium pressure, lower
values produced reduced bow pressure, and higher values produce increased bow pressure.
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