OsTIrus is a free software emulation of the legendary Access Virus TI synthesizer, delivering the unmistakable hypersaw-driven sound that defined trance, techno, and electronic music throughout the 2000s.
Built by The Usual Suspects, OsTIrus faithfully recreates the Virus TI, TI2, and Snow architectures while removing the hardware limitations that once held the instrument back.
OsTIrus reproduces the original DSP-based design of the Access Virus TI, including hypersaw oscillators, wavetable synthesis, grain tables, formant oscillators, and complex modulation routing.
Polyphony is not artificially capped and instead scales based on your system’s CPU performance, closely mirroring how the original dual-DSP hardware behaved at 133 MHz per chip.
Unlike the hardware unit, MIDI timing is sample-accurate inside modern DAWs, eliminating jitter and sync issues. Multiple stereo outputs are supported, making it easy to route Virus-style parts across complex mixes without external hardware.
OsTIrus supports high sample rates up to 96 kHz, offers fast preset browsing, and includes both instrument and effects versions of the plugin.
While the emulator itself is completely free, users must supply a legally obtained Virus TI firmware file, ensuring accurate DSP behavior and long-term compatibility with original patches.
Available on Windows, macOS, and Linux, OsTIrus runs in VST, VST3, AU, and CLAP formats, making it one of the most flexible hardware emulations currently available.
OsTIrus models the original DSP workload rather than enforcing a fixed voice count, so polyphony scales dynamically based on CPU performance.
Yes, original Virus TI patches load correctly when used with the appropriate firmware file.
The firmware contains proprietary DSP code needed for accurate synthesis behavior and legal emulation.
Yes, OsTIrus supports sample rates up to 96 kHz, reducing aliasing and improving high-frequency clarity.
OsTIrus works in most modern DAWs that support VST, VST3, AU, or CLAP, including Ableton Live, Logic Pro, Cubase, Bitwig, Reaper, and FL Studio.
The Mac plugins are not signed, if you get a warning such as “OsTIrus.xxx cannot be opened because the developer cannot be verified”, please ensure you carefully follow the instructions in the Installation Guide below.
