ER-301/Aliasing Triangle

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< ER-301
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Applications

  • Thru-zero FM synthesis
  • LFO with sync capabilities

Description

This unit is a simple triangle oscillator with inputs for both exponential and linear FM, and an internal VCA on its output. The linear FM supports thru-zero operation.

Tip-bulb.png
Where are the controls to change the waveform? You don't need them. The replace command in every unit's menu is a more powerful and general alternative which lets you replace any unit with another unit bringing over values and sub-chains of similarly named parameters. This works particularly well for quickly and smoothly replacing this unit with any of the other oscillator units.


Parameters

V/oct

Control Type Has Sub-chain? Sub-chain Parameters Fader Scale
Pitch yes transpose (-3600¢ to 3600¢) logarithmic ratio

This parameter is used to transpose the base frequency up or down according to an incoming modulation value that is V/oct calibrated (typically one of the inputs from the ABCD matrix). In other words,

Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle \text{f} = \text{f0} * 2 ^{\frac{x}{1200}} }

where Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://en.wikipedia.org/api/rest_v1/":): {\displaystyle x} is the value of this parameter (which is in cents). For example, if the base frequency (f0) is equal to 55Hz and this V/oct parameter is set to 2400¢, then the resulting frequency will be 220Hz (i.e. 2400¢ = 2 octaves which is 4x).

f0

Control Type Has Sub-chain? Sub-chain Parameters Fader Scale
Gain/Bias yes gain (-10,000 to 10,000)

bias (10 octaves above and below 27.5Hz)

frequency in Hertz


This parameter sets the fundamental frequency that is subsequently transposed by the V/oct parameter. Modulating this parameter corresponds to (thru-zero) linear FM.

sync

Control Type Has Sub-chain? Sub-chain Parameters Behavior
Threshold yes threshold (-1 to 1) trigger


A trigger into this parameter will cause the oscillator to reset its phase accumulator to zero. This is equivalent to the hard-sync on many oscillators.

Pitfall.png
This sync operation is not anti-aliased. So audio-rate triggering of this parameter will exhibit strong anti-aliasing artifacts which depending on the desired result could be a good thing or a bad thing.


level

Control Type Has Sub-chain? Sub-chain Parameters Fader Scale
Gain/Bias yes gain (-10 to 10)

bias (-1 to 1)

linear gain


This parameter controls an internal bipolar linear VCA on the output of the unit. It behaves exactly the same as the level parameter of a Linear Bipolar VCA unit.