S-4 changelog

Changes in S-4 OS v2.0.1

July 17 2025

This release fixes a few issues and bugs present in v2.0.

We added the possibility to format the internal disk for optimal playback of audio files in DISC. To optimize and format the internal disk, do a factory reset (CONFIG → SYSTEM → FACTORY RESET). Thanks to @boorch from the community, for the suggestion on optimizing sector/cluster size.

Bugfixes

  • Improved stability, fixing various freezes and crashes.
  • Fixed a bug where the display did not turn on when plugging in power.
  • Fixed a bug where the device was unable to save projects.
  • Fixed an issue where the PROJECT SAVED notification would display before the project was saved.
  • Fixed an issue where the sample browser is laggy when using an external USB drive.
  • Factory Resetting the S-4 improves DISC performance, limiting pops and clicks. We will address the remaining issues with playback in a coming update.

Enhancements

  • Significantly increased the frames per second of the display.
  • Added CONFIG → SYSTEM → FORMAT EXTERNAL USB DRIVE option when an external USB drive is connected.

Get the update at: https://torsoelectronics.com/pages/support

Find the update instructions in the manual.

S-4 OS v2.0

June 17 2025

Features

  • PERFORM: Global macros and punch-in effects for expressive, hands-on control. Map any parameters across the four tracks of the S-4 to the eight slider macros (supports unipolar and bipolar modes) or use the four action buttons as punch-in effects.
  • SCENE: Save and trigger up to 128 snapshots of full machine states per project. Use CHANCE and RULE to trigger chained scenes in sequence or randomly. Supports Program Change for easy external control.
  • TEMP: Temporarily change any parameter during performance and snap back instantly with the [TEMP] button.
  • COPY: Copy and paste scenes, tracks and devices with the [COPY] button.
  • DISC: New MATERIAL device for streaming audio directly from the internal storage.
  • FOLLOW: New envelope follower available as Modulation Source. Use internal or external audio as the control source, adjust fall and rise time, apply sample and hold and apply modulation to any parameter.
  • Track Launch: Start and stop any of the four tracks individually using the new Track Launch available in the Mix View. Track mutes moved to [CTRL] actions in the Mix View.

Enhancements

  • Optimized Internal Microphone: The internal microphone has been polished for a cleaner sound.
  • New Modulation Mapping Workflow: Modulation Mapping is updated for more seamless and intuitive mapping with momentary controls. While [MOD] is held, Mapping Mode is active – turn any parameter to apply modulation to that parameter. Tap an action button while [MOD] is held to switch Modulation Source, tap again to open the Modulation Source view.
  • Sample Preview: Preview samples directly in the Sample Browser by holding [CTRL] + [PLAY].
  • Track Record and Track Launch quantization options available in [CONFIG].
  • Quick actions enabled for [TRACK], [SCENE], [MIX] to overlay view-specific actions in any view.
  • Added option in CONFIG → METER for stopping Modulator transport when the S-4 is not playing.
  • Storage used is now indicated in CONFIG → SYSTEM.
  • Track Input and MIDI settings restructured in [CONFIG]. They are now under separate menus CONFIG → AUDIO and CONFIG → MIDI.
  • Inputs options renamed to IN1/IN2.
  • Added IN1/MIC input option.
  • Increased gain for line out and headphones.
  • Main Level is no longer bound to projects.
  • USB audio out is now post-fader, respecting levels set in the Mix View.
  • Settings in a Device are saved when switching Devices (or bypassing) in a Device Slot.
  • Tap an encoder while in Modulation Mapping Mode to switch between unipolar and bipolar mapping.
  • Inverted bipolar mapping added for modulation.
  • MAIN REC feature moved to [CTRL] + [PLAY] and features quantization, adjusted under CONFIG → METER.
  • Holding [TRACK] or [CLEAR] when changing device keep actions.
  • Reorganized [CLEAR] actions.
  • Updated CCs and MIDI NOTE implementation.
  • Buttons LED strength and color tweaked.
  • GUI Enhancements:
    • Modulation Mappings are now visually indicated in the GUI as well as via the LEDs on the S-4.
    • Updates to header includes showing current Scene instead of current device, MIDI in/out indicator removed and updated page indicator design.
    • Added scrolling slider to list views.
    • Smaller tweaks to layout, icons, device visualizations, etc.
  • TAPE: Enhanced TAPE device for the MATERIAL slot with new looping and overdubbing capabilities, as well as vari-speed recording.
  • TAPE and DISC monitor behaviour can be changed in [CONFIG] → METER.
  • RING: Added modes for the DECAY parameter.
    • SUSTAIN: Decay resonance is applied *after* filter cutoff, and WAVES/NOISE modulation.
    • CHOKE: Decay resonance is applied *before* filter cutoff, and WAVES/NOISE modulation.
  • DEFORM: Added modes for the CRUSH parameter.
    • BITCRUSH
    • REDUX
    • BITCRUSH/REDUX
  • DEFORM NOISE COLOR renamed to NOISE TONE.
  • VAST Added modes for the SPREAD parameter:
    • PHASE SHIFT: Shift the delay time in stereo
    • PING PONG: Alternate the delay between and left and right stereo channels.
    • DIFFUSION: Diffuse the delay for reverb-like effects
  • VAST: Feedback increased to 200%
  • VAST: The TONE parameter is now bipolar, allowing for both highpass and lowpass filtering of the delay feedback chain and reverb.
  • POLY: Can now be triggered via the [TRIG] action.

Bugfixes

  • Fixed issues with saving and loading projects.
  • Performance enhancements and optimizations to prevent crashes.
  • Optimized laggy interface in TAPE.
  • Fixed an issue where files could not be transferred to and from the S-4.
  • Fixed an issue where recordings didn’t play when transferred to a computer.
  • Fixed an issue where renaming projects in USB Mass Storage Mode didn’t affect projects when opening them up on the S-4.
  • Fixed crashes when entering USB Mass Storage Mode while sending CC.
  • Fixed an issue where sending CC to parameters could cause them to lock.
  • Fixed an issue where the first entry in a list couldn’t be deleted.
  • Fixed crashes when the internal storage becomes full.
  • Fixed an issue where the Global Tempo didn’t reset on new projects.
  • Optimized button presses so the S-4 no longer register double presses by mistake.

Updating to v2.x from v1.x

A rework of the S-4 filesystem requires an extra step when updating to v2.x from v1.x.

  • Upgrading from v1.x to v2.x requires you to remove all user data from disk. A prompt will guide you through the process—no data will be deleted automatically.
  • When prompted to wipe the S-4, the device will automatically enter USB Mass Storage mode. Simply connect it to your computer via USB to back up your files.
  • The v2.x installation cannot proceed if any user samples, recordings, or projects remain on the S-4.
  • When the installation is complete, you can transfer any user samples, recordings and projects back on to the S-4.

S-4 OS v1.2.2 Hotfix

December 9 2024

Bugfixes

  • Improved project buffer handling for long samples, enhancing overall loading stability
  • DEFORM: Fixed an issue where the DECAY parameter remained static and could not be adjusted

Known Bugs

  • While the improved buffer handling resolves some of the project load issues, it does not fix corrupted projects on save. Stay tuned for a completely revamped save system.

Get the update at: https://torsoelectronics.com/pages/support

Find the update instructions in the manual. Remember not to unzip the update file before transferring it to the S-4.

S-4 OS v1.2.1 Hotfix

November 5 2024

Bugfixes

  • TAPE: Fixed an issue where START and LENGTH did not initialise correctly after trimming a sample

Get the update at: https://torsoelectronics.com/pages/support

Find the update instructions in the manual. Remember not to unzip the update file before transferring it to the S-4.

Changes in S-4 OS v1.2.0

November 4 2024

Features

  • TAPE: TRIM action
    Samples can now be trimmed within the TAPE device. Use [CTRL] + [TRIM] to trim the sample within the loop region set by START and LENGTH. Trimmed samples are saved within the project and can be saved as a file using the [CTRL] + [SAVE] action to use elsewhere.
  • TAPE: Adding length to buffer
    Extending the LENGTH beyond the sample length in TAPE adds silence to the end of the sample.
  • TAPE: STRETCH mode
    This new mode retains the pitch of a sample regardless of TEMPO and global BPM, replacing the KEYLOCK action in TAPE. In STRETCH mode, PITCH can be offset freely, and GLIDE can be applied. STRETCH mode lives alongside the SYNC and FREE modes, and can be selected by pressing and holding the encoder for the TEMPO parameter.
  • TAPE: DENSITY parameter
    DENSITY controls grain size and rate for playback in TAPE. When TAPE is in FREEZE, DENSITY can be used to control the size of the frozen area, and in STRETCH mode it can be used to tweak the sound the loaded sample. It can also be used creatively with modulation. The DENSITY parameter is found on page two of the TAPE device.
  • MIX: Revamped DJ filters
    The DJ filters on the MIX page have been revamped to provide a smoother response.

    Enhancements

    • Significant DSP optimisation, reducing overall CPU load
      This includes increased performance when using POLY and MOSIAC together and when using the S-4 as an audio interface
    • Improved clock-in stability
    • Confirmation pop-ups added for CONFIG actions
    • Added option to reset device
      Under CONFIG → SYSTEM, there is now an option to do a factory reset of the device
    • Changed default modulators in new projects to RANDOM, RANDOM, WAVE, WAVE

    • TAPE: In FREE mode, recording no longer quantises the start and stop of RECORD
    • POLY: Added fade time to voice-stealing algorithm

      Bugfixes

      • Fixed an issue with audio buffers not clearing when loading projects, which could cause saving/loading issues
      • Fixed an issue where the S-4 became unresponsive after repeated saves and loads
      • Fixed an issue where long recordings could cause the S-4 to crash
      • Fixed an issue where CC control of time-based parameters didn’t follow the parameter’s quantisation settings
      • Actions without text no longer get highlighted when tapped

      • TAPE: Fixed an issue where overdubbing caused audio distortion
      • TAPE: Fixed an issue where initial overdubbing in a new project caused clicks and audio ducking
      • TAPE: The LENGTH parameter now instantly updates after START is moved towards the end of the sample
      • TAPE: Fixed an issue where the buffer length extended incorrectly while looping remained correct
      • TAPE: Fixed an issue where TAPE didn’t reset correctly after loading a project with TAPE in FREE mode
      • TAPE: Fixed an issue where TAPE in FREE mode didn’t reset correctly after reboot
      • TAPE: Fixed an issue where the loop region shifted when LENGTH was set below START
      • TAPE: Fixed an issue where configuring LENGTH could cause S-4 to freeze or crash
      • TAPE: Fixed an issue where changing START or LENGTH to a larger division didn’t snap to the nearest division
      • TAPE: Fixed an issue where moving START all the way to the right in FREE mode caused audio to stop
      • TAPE: Using [CLEAR] + [DEVICE] no longer stops TAPE playback
      • TAPE: Fixed an issue where buffer dirty indicator (“*”) didn’t appear until re-entering TAPE
      • TAPE: Fixed an issue where START became negative after loading an old project and creating a new one
      • POLY: Fixed an issue where certain sequencers caused POLY to trigger notes twice

        A special thanks to our beta testers for helping us with testing and giving feedback on this update!

        Get the update at: https://torsoelectronics.com/pages/support

        Find the update instructions in the manual. Remember not to unzip the update file before transferring it to the S-4.

        Changes in S-4 OS v1.1.0

        September 6 2024

        Features

        • MIDI sync in/out
        • Analog clock sync in/out
        • TAPE: Added SYNC and FREE modes for TEMPO

        Enhancements

        • Changed MIDI Config menu names for clarity
        • VAST: Tweaked slew limiting of delay time
        • POLY: Added icons for loop modes
        • POLY: Voice is released when sustain reaches 0

            Bugfixes

            • Fixed a crash when sending multiple CCs to the same parameter
            • Fixed a visual bug where sending CC to one parameter made the same parameter on all other tracks move
            • Choosing same device in the device selection menu, no longer causes device parameters to reset
            • Fixed an issue where OS updates were not correctly applied to the S-4
            • TAPE: Fixed an issue where long samples did not load on saved projects
            • TAPE/POLY: Fixed an issue where switching from POLY to TAPE caused TAPE to have irreversible negative values on START and LENGTH
            • POLY: Removed aliasing on short envelopes
            • POLY: Fixed an issue where a small part of the start of the loaded sample was played, when the envelope reached end of the waveform
            • POLY: Fixed an issue where the start point of the sample was inconsistent as multiple notes were played
            • POLY: Fixed an issue where mono samples were not displayed correctly
            • POLY: Removed audible pops when using the ping pong loop mode
            • VAST: Delay freeze no longer drifts over time
            • VAST: Fixed an issue where the delay feedback became shifted as SPREAD was moved
            • MIX: Fixed an issue where parameters on the MIX page did not change using CC from external USB devices
            • RANDOM: Fixed an issue where modulator went out of sync as length was changed

              Get the update at: https://torsoelectronics.com/pages/support

              Find the update instructions in the manual. Remember not to unzip the update file before transferring it to the S-4.

              Changes in S-4 OS v1.0.4

              June 19 2024

              Enhancements

              • An animation now indicates when the S-4 is busy
              • Update .zip file is now automatically removed after update
              • Encoders can now be used to navigate the sample and project browser
              • Both updates and factory sample packs can be installed from external USB drive

              Bugfixes

              • Fixed crashes when saving and loading projects
              • Fixed issue where old parameter ranges were used when loading projects created in previous firmware
              • Fixed an issue where free rates did not save in projects
              • Fixed an issue where audio config settings did not load correctly
              • Fixed an issue where parameter modes did not reset correctly when creating a new project
              • Fixed an issue where the firmware version was wrongly displayed in the system config
              • Turning an encoder in an empty folder in the sample or project folder no longer causes the S-4 to crash

              S-4 OS v1.0.3 Hotfix

              June 13 2024

              Bugfixes

              • TAPE: Fixed issue and issue caused by previous update, where Start and Length parameters did not load correctly.
              • TAPE: Fixed issue where GUI grid division did not update accordingly when loading project.

              Changes in S-4 OS v1.0.2

              June 5 2024

              Enhancements

              • RING/VAST/RANDOM/WAVE: Lower rates for time-based parameters.
              • TAPE: The timeline now updates instantaneously when selecting a sample, so it is more apparent when longer samples are being loaded.
              • RANDOM: Improved Smoothing parameter. Values up to 70% now behave more like a glide.
              • VAST: Improved Damp and Spread behavior when Freeze is enabled.

              Bugfixes

              • TAPE: Length of loaded samples is increased to 6 minutes.
              • TAPE: When Tape is in Freeze mode, the playhead no longer moves forward when adjusting Start or Length. The playhead will resync when Freeze is disabled.
              • TAPE: Fixed a bug where Start and Length grid division was not linked.
              • VAST: Toggling Freeze no longer causes delay line to self-oscillate.
              • VAST: Damp no longer increases delay feedback
              • RANDOM/WAVE: Rates in Free are now independent from BPM.
              • RANDOM: Modulator no longer goes out of sync when changing rate.
              • RANDOM: Variation parameter now affects the last step of modulation.
              • Fixed USB audio in artefacts on ch. 5/6, 7/8, 9/10

              Changes in S-4 OS v1.0.1

              May 23, 2024

              Enhancements

              • MOSAIC: Increased grain size

              Bugfixes

              • S-4 won’t turn on in some cases
              • TAPE: Recorded audio plays too fast
              • Crash when saving project with punctuation
              • Brightness adjusting wraps when pressing select or pressing encoder
              • Track inputs bleed

              S-4 OS v1.0.0

              April 28, 2024

              • Initial release