Answers to Some Common Questions

1.The VL70-m is a monophonic tone generator. Why is the “poly” mode initialy selected when the VL-XG sound module mode is engaged?

This is to provide compatibility between the currrent XG format and future polyphonic VL- series tone generators. It also provides a certain degree of compatibility to allow playback of VL-XG song data on existing tone generators which do not feature the VL-XG extension. Specifically, to switch the VL70-m to the mono mode a “mono mode” command (control change no.126, value 0-16) is embedded in the song data which, when received by a 32-note or 64-note polyphonic XG tone generator, switches the appropriate parts to the mono mode. The same will apply to future polyphonic VL-series tone generators, so no changes will be required. The VL70-m therefore has a “poly” which is automatically selected when a MIDI “XG on” system exclusive message is received.

2.Can the Treble and Bass parameters be edit during performance or playback?

In fact, they are a valuable expressive tool. Although the Treble and Bass parameters are basically similar in effect to the corresponding controls on an amplifier, for example, their actual effect varies slightly from voice to voice. In many cases they also affect the critical mid- frequency range, making it possible to give a voice extra “presence”, as required. The Bass parameter, in particular, can be used to bring a voice “forward” in an ensemble.

3.Why do 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.

4.Why does portamento produce more of a glissando effect on some voices?

Trumpets and some other brass instruments tend to exhibit this phenomenon more than others. In a S/VA tone generator portamento is produced by lengthening or shortening the instrument’s pipe or string and changing the Embouchure. A trumpet is designed to empha- size the “modes” of the pipe(s) to produce notes over a wide range using only three valves. When portameto 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.

5.Why do the filter, EG, and other parameters have more effect on some voices than oth- ers?

Most voices use the low-pass filter type, but some use the bandpass, high-pass, or band eliminate types. Some voices use very little filter processing at all. Changing the filter settings may not produce a particularly notice- able effect. Also the internal Breath Noise, Throat Formant, Growl, Harmonic Enhancer and Pitch EG parameter settings can have a significant effect on how much the parameters accessible via the VL70-m controls actually affect the sound. For detailed programming of all S/VA parameters, use the VL70-m Expert Editor software(page 25).

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