Updating your OS on a PC

Before starting, close all other audio or MIDI or DAW software, and disconnect all other MIDI devices.

Note: Tempest can only be updated via USB after Main OS version 1.2 is installed. If your Main OS reads less than 1.2, you'll need to update via the MIDI jacks first.

If you're on a PC, there is a free MIDI utility called MIDIOX. You can download MIDIOX at the following link:

  1. Download and install MIDIOX.
  2. Decide if you're going to update via the MIDI jacks or USB. Press the System button on the Tempest and navigate to the "MIDI: SysEx IN+OUT Cable" option and select either "MIDI" (for the MIDI jacks) or "USB". If you are updating from Main OS 1.0 or 1.1, see the *Notes section at the bottom.
  3. After installing, launch MIDIOX. Attach a MIDI cable from your MIDI interface to the Tempest's MIDI in port (attach a USB cable from your computer to the Tempest's USB port if using USB). In MIDIOX, select "Configure Buffers" from the pull down menu labelled "Options". Set the "Low Level Output Buffers" "Num" and "Size" to "1024" bytes. Click "OK" to close the window and save the settings.
  4. Next, select the "Options" pull down menu and choose "MIDI Devices" . In the lower left quadrant of the window click on the MIDI port which is connected to the Tempest (or select Tempest if using USB). The selected MIDI port will appear in the top right quadrant of the window in the "Port Mappings" window. Click "OK" to close the window and save the settings.
  5. Now, under the "View" pull down menu select "SysEx". The "SysEx" window will open. Select the "Command Window" pull down menu and choose "Load File". Browse for and select one of the 4 Tempest update files. From the "Command Window" pull down menu, select "Send Sysex" to start file transmission.
  6. The Tempest's display will update with a numeric countdown indicating the progress of the SysEx file's transfer. Follow any directions listed on the Tempest's screen before/after the countdown completes. If you find the countdown stops and does not complete for any reason such as freezing on a number before countdown reaches zero or displaying a "Status Byte Received In Data" message, restart the Tempest by powering it off/on and try again. DO NOT power down when Tempest says "Writing Now!".
  7. Double the "Low Level Output Buffers" "Num" and "Size" values and re-send the SysEx file to the Tempest. If the countdown gets closer to zero, then you know your settings are moving in the right direction. If the countdown goes further from zero try reducing the "Num" and "Size" settings. You can also try doubling or quadrupling the "Size" setting. You may have to adjust the "Low Level Output Buffers" several times before finding the right combination.
  8. If you received a "Statuts Byte Received In Data" message, it means some other MIDI message the Tempest was not expecting was sent through your MIDI interface. Make sure all other audio or MIDI or DAW software is closed, and no other MIDI devices are connected. If you continue to receive this message try restarting your computer and open MIDIOX as your only application.

After successfully installing the file, restart the Tempest by powering off/on, then send the next OS file to the Tempest. You can check the installed versions of the software by pressing the "System" button on the Tempest and navigating to the "Show System Information" option. The order in which you send the OS files should not make a difference.


  • Most MIDI interfaces or sound cards with built-in MIDI interfaces will work. However, we do NOT recommend any Digidesign/Avid interfaces or Native Instruments Maschine for updating our instruments as they do not transmit Sysex correctly for updates. Alternatively, the M-Audio Uno as a cheap and widely available MIDI interface for use when updating your products. You can find them online for as little as $30-$40.
  • If you are updating from Main OS 1.0 or 1.1, a new global preferences parameter has been added on the 1.2 Main OS. The "Sysex IN+OUT Cable" parameter sets whether the Tempest receives Sysex update files through the USB or the MIDI DIN port. Make sure to set the parameter to the port you wish to send the updates through after updating to the 1.2 MAIN OS. To do so, press the "Global" button to enter the global parameter preferences. Scroll to the menu item labelled "Sysex IN+OUT Cable" and set it to "USB" or "MIDI".
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