The Tva Section - Roland V-Synth Book

The TVA Section

TVA stands for Time Variant Amplifier, and this is the section which governs the
overall volume of each note while it is being played - including master volume (Level),
the envelope itself, keyboard velocity, panning and tremolo (via the dedicated LFO).
Having been introduced to envelopes earlier in this tutorial, you should already know
how to set up the most important parameters, but I will go into more detail here.
✱ T T h h e e T T V V A A s s l l i i d d e e r r s s o o n n t t h h e e p p a a n n e e l l c c a a n n b b e e u u s s e e d d f f o o r r a a n n y y o o f f t t h h e e V V - - S S y y n n t t h h e e n n v v e e l l o o p p e e s s - -
w w h h e e n n e e v v e e r r o o n n e e i i s s v v i i s s i i b b l l e e o o n n t t h h e e s s c c r r e e e e n n ! !
If TVA is deactivated, this is practically the same as setting maximum level, minimum
Attack and Decay, maximum Sustain and Release of 15. Release is not zero here
because cutting the sound off too suddenly would cause a click. Start with 512:INIT
PATCH and try out the following:
Level KF
Lvl LFO Dp
Pan
Pan KF
Pan LFO Dp
Curve
Sens
A-Sens
D-Sens
R-Sense
Env Time KF
22
Level KeyFollow. Level follows the MIDI note - try setting -200 and play
all the 'C' notes on the keyboard starting from the lowest one. Then set
Level KF to +200 and play each of these notes again. You should now
know what "KeyFollow" means! Set Level KF back to +0 and press the
cursor-right button to highlight the next parameter...
Level LFO Depth. Amplitude modulation from the TVA's own dedicated
LFO. Useful as a tremolo effect - try different values. Set Lvl LFO Dp
back to +0 and press the cursor-right button again...
Panorama. This moves the sound to the left or right. Try extreme values,
then take it back to zero.
Panorama KeyFollow. In a similar way to Level KF, the panorama position
will follow the notes on the keyboard. Note that panning is polyphonic,
i.e. if you play the lowest and highest notes on the keyboard at the same
time, they will be split in the stereo field. Try it!
Panorama LFO Depth. Try extreme values for a deep stereo tremolo effect.
At zero, this is flat i.e. the level (as well as some other values we will come
to shortly) is always the same, no matter how hard you play the keyboard.
The small graph indicates keyboard velocity in the X-axis, and how this is
translated into levels in the Y-axis. For instance Curve 1 means that keyboard
velocity is translated linearly, whereas Curve 3 means that it will take a lot
more energy to reach medium levels. Try playing the keyboard very
dynamically using each of these curves in turn - you will soon get a feeling
for each one, and understand intuitively what each individual graph depicts.
Sensitivity. This parameter governs the degree to which keyboard velocity will
affect Level. The default value is +32, but with Velocity Curve at 1, values
around +27 are better (for my personal playing style at least). Note that setting
negative values here will make the sound softer the harder you play. Set Sens
to +0 so you can hear the effects of the following parameters in isolation:
Attack Sensitivity. The Attack time is affected by how hard you play the
keyboard. Try setting A-Sens to +63 and the nominal Attack (using the
A slider) to 40, then alternate between playing very softly and very hard.
When you are finished, take both A-Sens and Attack back to zero.
Decay Sensitivity. The Decay time can also be affected by keyboard velocity.
To make Decay longer when you play harder, you will have to set negative
values here. Set D-Sens to -50, Decay to 50 and Sustain to zero. Alternate
between playing very softly and very hard, then set D-Sens back to zero.
Release Sensitivity. Similar to A-Sens and D-Sens, but affects Release time.
Envelope Time Keyboard Follow. Envelope times follow the MIDI note.
Setting positive values here shortens Attack, Decay and Release (all at
the same time) when you play higher notes, and lengthens them when
you play lower notes. You will hear this effect when playing a piano.