Astrel™ Polyphonic Synthesizer

Astrel™ is a warm, characterful polyphonic synthesizer with analog-style oscillators and filters, a deep modulation matrix, an arpeggiator, a 64-step chord sequencer and built-in studio effects. Use it in your DAW as a VST3, Audio Unit (AU) or AAX instrument, or play it on its own with the included standalone app. No DAW required.

Sound

Two oscillators per voice

Saw, triangle and pulse waves can all run at once, plus a sub-oscillator one octave down and white or pink noise. Hard sync and through-zero FM give you everything from snarling leads to metallic bells. The oscillators are carefully band-limited, so they stay clean and alias-free even at extreme settings.

A filter that morphs

A smooth 2-pole filter sweeps continuously from low-pass through notch to high-pass, with a band-pass mode and gentle built-in saturation. A separate clean high-pass and low-pass pair shapes the sound before the filter, or runs in parallel with it for two bands at once, for vowel-like formants or a dry blend.

Real analog character

The Vintage control gives each voice its own small tolerances and slow drift, the way analog hardware behaves. Per-voice overdrive adds grit when you want it.

Five voices, played your way

Play it polyphonically, or stack up to five voices in unison with adjustable detune. Four portamento modes cover fixed rate, fixed time and legato-only glides.

Movement

• Two DADSR envelopes with natural, analog-style curves and optional looping

• Two LFOs, one global and one per voice, with five waveforms, rates up to 500 Hz and tempo sync

• A 16-slot modulation matrix with 20 sources and 66 destinations, including audio-rate modulation of pitch, filter cutoff and more

• An arpeggiator with Up, Down, Up+Down, Random and Assign modes over 1 to 3 octaves, with Hold, tap tempo, sync to your DAW and a probability control for patterns that breathe

• A 64-step sequencer that records chords of up to five notes with per-note velocity, rests and ties. Hold a key to transpose the sequence live. Play it forward, backward, ping-pong, at random or as a random walk, and let probability and mutation vary it as it plays. Every step can also carry a modulation value, so the sequencer can drive the filter, the effects or anything else in the matrix, alongside its notes or on its own while you play the keys. Sequences are saved with each patch.

Effects

Twelve effect types: stereo, BBD and tape delays (tempo-synced), chorus, flanger, phaser, high-pass filter, distortion, ring modulator, rotating speaker and lo-fi. These are followed by a lush plate reverb. Every effect knob can be modulated.

Presets

• An original factory bank of 305 presets in eleven categories: basses, leads, pads, keys, brass, strings, plucks, bells, FX, arpeggios and sequences

• A preset browser with search, categories, favorites and your own star ratings, sorting by name, rating, newest or most used

• Save your own presets, shared between the plug-in formats and the standalone app

• The factory bank appears in your DAW's preset list in VST3 and Audio Unit hosts, and in Astrel's own browser everywhere

Plug-in formats

• VST3 on macOS, Windows and Linux

• Audio Unit (AUv2) on macOS, for Logic Pro, GarageBand and other AU hosts

• AAX on macOS and Windows, for Pro Tools

Each installer installs every format available on your system, along with the standalone app. One license covers them all.

Standalone app

Play Astrel without a DAW: choose your audio and MIDI devices (on Windows, WASAPI or your audio interface's ASIO® driver for the lowest latency), play the resizable on-screen keyboard or your MIDI controller, and record your performance straight to a 24-bit WAV file. Your settings and last sound are restored every time you open it.

Expressive control

Astrel responds to velocity, pitch bend, mod wheel, aftertouch, breath, foot and expression controllers, and the sustain pedal. With MIDI Learn, any other knob or slider on your controller can take over any control: click LEARN, click a control, move a knob. Low Split drops the keys below a split point by one or two octaves for instant bass-and-lead playing.

System requirements

• macOS (Apple silicon and Intel)

• Windows (64-bit)

• Linux (64-bit, x86_64): .deb package for Debian and Ubuntu, or a tar.gz for other distributions

• To use it as a plug-in: a VST3 host (macOS, Windows, Linux) an Audio Unit host (macOS) or Pro Tools (AAX, macOS and Windows). The standalone app needs nothing else.

Licensing and trial

One license activates Astrel on two computers at a time. Activation needs an internet connection once, after which Astrel works offline for up to 30 days between check-ins. You can move a license to another computer at any time by deactivating the old one.

Try before you buy: without a license, each instance of Astrel inserts one second of silence once a minute, or every 10 seconds when rendering offline.

Astrel™ is a trademark of Tristar Advanced Software, LLC.