The Yamaha VL70-m tone module is a monophonic "Virtual Acoustic" synthesizer based on Physical Modeling. The use of physical modeling allows the module to emulate many different kinds of (acoustic) instruments. The VL70-m manual gives a good explanation of the exact techniques used in this piece of equipment. A more general explanation can be found at Physical Modeling Synthesis. In brief, it uses special algorithms that emulate reed, lip, air or string vibrations like in clarinet/sax, trumpet, flute or violin. Next to that, it uses the shape (tube, cone, case) for building up the sound. These algorithms can be controlled by the player using embouchure, throat, bowing, tonguing, pressure, growl, pitch, etc. like on the real thing. There are a number of sound modifiers to enhance the sound, like harmonic enhancer, dynamic filter, frequency equalizer and resonator.
This technique makes is possible to create real sounding acoustic instruments, but also complete new instruments by combining its possibilities, e.g. a bowed clarinet or a flute-like violin.
The VL70-m has 4 sound banks; PRESET 1 with 128 built-in sounds, PRESET 2
with 128 built-in sound, CUSTOM with 6 free sound slots and INIT where you can store customized sounds from the other three banks.
I mainly use my two VL70's to play real acoustic instruments. The built-in sounds are very nice, but there are a few possibilites to get more out of this module. Both my VL70's have been upgraded with a TurboVL chip. This chip replaces the original sound chip and gives the VL70-m a whole new meaning. Not only are there more acoustic instruments, replacing many of the never used original sounds, but they're also of a higher quality offering more realism. On the other hand they need some editing as well, especially on the, to my taste, too heavy effects settings.
I can still store some of the sounds from the original chip in one of the six slots of the CUSTOM bank of each VL70-m.
Owning two VL70-m's enables me to stack sounds to emulate a small ensemble or play different sounds for melody and solo parts without the need to change patches. With the transposing features of the module you can play intervals on two modules. To do this, I have built a MIDI THRU interface that can switch the MIDI data to either of the two modules ON and OFF. Using foot switches I can either layer two sounds or quickly change modules without having to use any other controls.
When you want to create your own sounds for the VL70-m you'll need an editor for Mac or PC. Go to VL70-m Software Downloads on YamahaSynth.com for an overview of available editors and other downloads.