This upgrade page is only for registered OB-Xtreme version 1.x owners

If you do not own an OBXtreme v 1.0 license use the general OB-XTRM 2.0 page

V2.0 upgrade

New features, refined engine, Cross-Platform and 64bit, full info on the main page

OB-Xtreme version 2 is now available for € 45 EUR.

As a OB-Xtreme version 1 owner you can upgrade for free ( € 1 EUR symbolic so I can receive notification from Paypal) you can also choose to support me by paying the upgrade amount or the regular amount.
check out the new features below.

Thanks for your support!

There is a lot to say about what V2 is, I can already say what it is not : a simple V1 cross-platform update. V2 is a full remake, while OB-Xtreme V1 was a simpler take on an OB voice card architecture, V2 is more closely related to original OB designs and specs (including features from OB-X, OB-Xa etc) it is not a direct V1 replacement, nevertheless it got a Legacy mode for Envelope Generators and Filter control so V1 sounds can be reproduced or made (more on that later).
V2 have higher specs in every part of the circuit, it comes as an upgrade gift to all V1 owners, V1 owners can update for free or use a "give what you want" option.

Get OB-XTRM 2.0 Upgrade!

Main features

The summer 2022 pre release was the full functioning synth minus the v2 factory presets (only v1 bank + some extra were included, LFO2 wasn't active). Since then additional work have been done for Release version which features many improvments, more controls on voltage offsets (portamento offsets! you know you want that), more modulations and better logic. Design sounds and funk it up with some brass stabs, cutting leads, lush pads and screaming bass.

A complete list of OB-XTreme 2.0 features is provided below, in a nutshell OB-Xtreme can act as an 8 voice polyphonic, 8 voice unison mono or true (one voice) mono, a FAT mode engages the unison while also providing polyphonic unison, that means 8x8 voices power.
Most OB-X/OB-Xa functions are provided, including SAW, PULSE, TRI oscillators shapes and the peculiar SAW+PULSE which can produce an interesting +1 OCT harmonic depending on the pulse width setting.
the 2Pole filter is based on the OB-X and the 4Pole is based on the CEM3320 implementation, the 2pole has that classic SVF linear "singing" resonance across the bandwidth while the 4pole will resonate less at lower cutoff values (a bit Moog like), a bandpass output is also provided in 2pole mode while 4pole have an optional volume loss compensation.
The Xtreme factor is the main control over the emulated OTA enduced distortion, one chip in particular the CA3080 was used a lot at different places in the circuit (although less and less over the OB synths evolution). OB-Xtreme gives some control over that, you can push them way beyond the original specs or stay at minimum for more traditional behavior, you can also bypass PRE or POST circuits for versatility. The PRE stage will act more on lower notes while the POST stage is linear across the range.

Another feature is the under the hood access so you can control the 8 voice cards voltages across the main parts. The cards variations are an important factor to mimic the analog character, while using a VCM (virtual component modeling) approach, I wanted something effective but not time consumming so I designed some pre-defined offsets and deviations that you can dial in or scatter across all 8 voices.
You get seven macro sliders: OSC (which doubles on the front panel as the "SPREAD") controlling OSC 1 and 2 tuning offsets, FILT filter envelopes offsets, AMP for amplitude envelope offsets, VCF for VCF deviation, PW for pulse width offsets, PORT for portamento glide time lag and XMOD for cross modulation offsets. Additionally you can toggle a realtime small random deviation per note or randomize and scatter deviations around. Voltages offsets reflect on the GUI as positive or negative voltages (yellow/blue).
I removed a not so usefull temperature function that changed the EG timing to make room for individual card tuning, the cards tuning in semitone (+1 OCT range) can give interesting results, we can have a ressembling chord mode when using unison (FAT) mode.

Get OB-XTRM 2.0 Upgrade!

OB-XTRM 2.0 New Features

  • Cross Platform 64bit capability (Windows VST3 and Mac AU(Audiounit).
  • 64bit build using latest OS and IDE(PC VisualStudio and Mac Xcode).
  • Updated GUI(graphic Interface) also now using high-res graphics and DPI awareness.
  • Rewritten and Refined sound engine.
  • 8 voices poly or mono unison with per voice PAN control and global stereo widening control, can also turn into real (one voice) mono or act as polyphonic unison (8x8).
  • Most of OB-X/OB-Xa functions added (OSC shapes, X-MOD, F-ENV, SYNC etc) on top of new modulation routing.
  • Enhanced oscillators spectrum and filter modes (2Pole/4Pole LowPass and 2Pole BandPass) based on OB 2pole SVF and CEM 3320 24Db, 4Pole can have an optional volume compensation.
  • Accurate SAW + PULSE OSC mixing (can produce +1 octave harmonic depending on the pulse width).
  • Up to x32 oversampling.
  • POST and PRE OTA (CA3080 chip used for VCA, Filter and Output Stage) variable distortion (Xtreme factor) with bypass.
  • x8 Voice cards voltage offsets and deviation can now be controlled easily by seven macro controls, optional random propagation and realtime deviation (per note).
  • Legacy modes for Filter modulation and EG/VCA shapes to match V1 sounds and behavior if needed, the default envelope/VCA behavior is the CEM3310/CA3080 combo (Linear VCA and exponential envelopes) while the legacy mode can be used for more snappy sounds (using an ultra exp VCA response).
  • Vibrato LFO, original LFO + additional LFO 2, Phase reverse option mode for LFO 1 & 2 (card 1,3,5,7) got phase reversed modulations, can also invert Keytracking.
  • LFOs have gate re-triggering option, SINE, RAMP, PULSE, SAW, TRI, S&H and Noise shapes, LFO2 can be BPM synced or act as a one-shot ramp (up or down) envelope.
  • LFOs can be set to single: one LFO on the main board for all voice cards or to multi: one LFO per card
  • Optional OB-X 6bit resolution on the Filter Cutoff knob scanning.
  • Sustain pedal can act normally or use the OB Mode (sustain like piano) controllable Envelope Release offset.
  • (Mac) Introducing new Mac Signed and Notarized Installers.
  • Basic internal preset browser with main categories.
  • OB-X (light mode) or OB-Xa (dark mode) changeable skins.
  • OB-XTRM 2.0 features 2 legacy modes to match version 1 behavior or give another flavor if needed:

    FILTER CONTROL MODE gives "Hardware" option which is the typical OB implementation (Cutoff knob controls the filter frequency, modulation adds the envelope amount)

    "Legacy" option is the custom v1 implementation (Cutoff knob controls voltage is multiplied by modulation) which gives a different behavior, the range of the filter cutoff in this mode can get lower than the hardware mode.

    ENVELOPE and VCA TYPE gives "CEM 3310 EG - LIN VCA" option which is the typical OB-X implementation (Exponential envelopes generated by the CEM 3310 chip into a Linear VCA)

    "LEGACY EG - EXP VCA" option is the custom v1 implementation (custom attack shaped envelopes into peculiar Exponential VCAs acting before and after the filter.) it can be used for matching v1 sounds or to give another flavor.


    Windows 10 and higher, 64bit host, plugin provided format is VST3.
    Not supported but has been proved to work on Windows 7.

    Mac OS:

    Mac OS (10.14) to Mojave or higher, 64bit host, plugin provided format is AU (AudioUnits).
    Not supported but has been proved to work down to Mac OS (10.12.6).

    About AudioUnits format:

    AU is Apple s proprietary audio technology, part of the Core Audio provided by Mac OSX. It is part of the operating system so it provides low latency and system-level support for the interface. Most DAWs developed for Mac OSX support the Audio Units interface due to its stability and system-level solutions (which also means faster processing). Apple Logic only utilizes Audio Unit format plugins, but other DAWs such as Ableton can also use these.

    One or two DAWs like for example Cubase do not support Audiounits directly yet but you can still easily load an AU plugin with the help of a VST host plugin, some popular solutions are DDMF Metaplugin or BlueCat's Patchworks, a popular free one that recently got open sourced is KUSHVIEW ELEMENT. You will find info and a direct link to latest free binaries at the support/OSX Support part of my website.


    Avid Protools only supports its proprieratary format AAX at the moment but you can still easily load an AU or VST plugin with the help of a VST/AU host plugin, some popular solutions are DDMF Metaplugin or BlueCat's Patchworks, others might be available that I am not aware of yet.

    Other info:

    32bit is not supported ATM
    Mac M1 handles it fine (rosetta 2) even if not compiled for native ARM yet. Native ARM/INTEL as universal binaries as well as Mac VST3 format are in the making.

    Get It !

    Get OB-XTRM v2 upgrade for Windows & MAC

    OB-XTRM 2.0 comes with both Windows & Mac Installers and Manual
    *works on Mac M1 even if not native ARM yet (see compatiblity info tab)