Alesis A6 User Manual

Chapter 5: Oscillators and Filters

A

NDROMEDA 

A6 R

EFERENCE 

M

ANUAL

113

FREQUENCY

The frequency of 

 or 

.

SQR WAVE LEVEL

The output level of the selected VCO’s
square wave.

PULSE WIDTH

The pulse width of the selected VCO’s

square wave.

OSC2 -> PWM (Oscillator 1 only)

The output of 

 feeding into the

pulse width modulation of 

 .

OSC2 -> LIN FM (Oscillator 1 only)

The output of 

 feeding into the

linear frequency modulation of 

 .

OSC2 -> EXP FM (Oscillator 1 only)

The output of 

 feeding into the

exponential frequency modulation of

 .

EXT -> PWIDTH

The output of 

 (white, pink, red, or

) feeding into the pulse width of the

selected VCO.

EXT -> LINFM (Oscillator 1 only)

The output of 

 (white, pink, red, or

) feeding into the linear frequency

modulation of the selected VCO.

EXT -> EXPFM

The output of 

 (white, pink, red, or

) feeding into the exponential

frequency modulation of the selected

VCO.

PWMOD/PWM Parameters

Both VCOs provide for 

 

or Pulse Width Modulation, shown as 

PWMOD

 on the

display. This means that the width setting of the pulse wave set by the 

knob can be varied by a modulation source. This mod has been popular for years and

has been used to re-create many well-known sounds ranging from lush string
ensembles to thick synth pads.

When the 

 button is pressed on either VCO, the display shows the pulse width

modulation parameters for that VCO. A VCO’s pulse width is most often modulated
by an LFO, but it can easily be modulated by an envelope, the keyboard (velocity,

aftertouch or key track), the pitch bend and modulation wheels, pedals and ribbon
controller, just to name a few of the 79 possible sources in the A6. See Appendix B for
a complete list.