FXpansion has announced that ORCA, a free experimental monosynth based on detailed and accurate models of analogue synthesizer circuits and components, is now available in RTAS (Pro Tools) and AU (Mac) format. ORCA was previously released in VST format.

According to the company, “ORCA is an experimental monosynth built to showcase some exciting new technology that we’ve been developing. Based on detailed and accurate models of analogue synthesizer circuits and components, ORCA excels at deep, squelchy basses and thick unison leads.”

Orca is a free download, but registration at the FXPansion site is required.

ORCA Engine Overview

Orca has a simple subtractive synthesis structure, being comprised of an oscillator, filter, fixed amp envelope, velocity sensitive filter envelope and an amp module. The monophonic voice engine in Orca runs at twice the hosts sample rate to reduce the aliasing caused by the non-linear analog modeling of the filter and amp modules. A voice priority of newest note is used, and every new note re-triggers the amp and filter envelopes.

The oscillator is a fixed Saw (75% volume) plus Sub Sqr (25% volume) that has continuously smooth varying unison from 1 to 9 voices, and a detune parameter from 0 to 12 semitones. Oscillator sync is available from the mod wheel of up to 48 semi-tones.

The BLEP technique is used to bandlimit steps generated by the analog model of the oscillator. Since the oscillator is passed into several non-linear stages care is taken to have a fairly smooth time domain transition on waveform jumps, which results in less aliasing.

Orca is free to download. ORCA is available as a VST 2.4 plug-in for Windows (XP) and OS X (10.4 PPC and Intel), and can be used in other hosts (Audio Units, RTAS) via our VST-RTAS or VST-AU Adapters.