Abstrakt Instruments Avalon Reference Manual - page 11
11
AVALON - Reference Manual
3 ANALOG SYNTH
3.1 ZERO THE SYNTHESIZER
Before starting to program a pattern it is a good idea to reset the analog synth voice to the default settings to ensure sound will be heard when a
pattern is played.
The analog voice of the Avalon is backwards compatible with the Roland
®
TB-303. The additional features can be viewed as a layer on top of the
original TB-303 which greatly expand the capabilities without being cumbersome or overwhelming. Together with the external filter cartridges
from the Synth Cartridge System
™ the Avalon is an extremely flexible mono synth with capabilities far beyond the TB-303 subset of sound and
performance.
The analog controls are laid out in a straightforward manner.
3.2 OSCILLATOR
TUNE sets the master tune of the oscillators. The range of the control
is +/- 500 cents.
SUB/INPUT controls the level of the Sub Oscillator. When the external
input is used the Sub Oscillator is bypassed and it controls the
external input level.
The SUB and MAIN switches select the waveform for the main and
sub oscillators. When the main oscillator switch is set to the center
position the main oscillator is turned off. The
switch selects
the sub oscillator between (-1) and (-2) octaves. When the switch is
pushed to the "in" position the sub oscillator is set to (-2) octaves and
the indicator lights up for visual confirmation.
3.3 FILTER
CUTOFF adjusts the cutoff frequency of the filter. The internal filter
is a low-pass diode ladder filter (TB-303), so in this case it controls the
low-pass cutoff frequency. External filter cartridges may have any
topology, so in these cases the CUTOFF control may relate to high-
pass, low-pass, band-pass, or notch frequency depending on the
topology and filter mode of the cartridge being used.
RESONANCEsets the emphasis amount at the cutoff frequency.
TRACKING sets the key tracking amount. This determines how
much the filter cutoff frequency tracks the keyboard. The tracking is
purposely non-linear with regards to keyboard scaling, so a one
octave increase in key pitch will never correspond to a one octave
increase in filter cutoff frequency for all notes. It is desirable to have a
greater response at lower octaves in a bassline synthesizer. In the
case of the Avalon the tracking is logarithmic, so tracking becomes
progressively greater at lower octaves and progressively gradual at
higher octaves. The changeover key for tracking is D#2 (77.78Hz), so
as tracking is increased notes below D#2 will decrease the filter cutoff
frequency and notes above it will increase the cutoff frequency.
The switch labeled
is a hardware switch that selects between
the internal TB-303 filter and an external filter residing on an optional
filter cartridge. When the switch is in the 'out' position the internal
filter is selected. When the switch is pushed to the 'in' position the
filter plugin cartridge is selected and the LED indicator in the filter
section lights up for visual confirmation that the external cartridge
has been selected.
The
switch stands for frequency response (or full range) and selects
the low frequency response of the audio signal to the VCA. When the
switch is in the 'out' position the frequency response rolls off at 70Hz.
When the switch is pushed to the 'in' position the frequency response
extends down below 30Hz.