GR-MEGA firmware 1.5.0 release notes

Recording overhaul.

Date: 28 November 2025

New features:

- #1443 Op encoder menu - option to toggle "soft cut" mode.. this crossfades crops at the extreme end to create a wrapping sample
- #1553 Sampling menu - growing record buffer. Select Sized = Auto.
- #1425 Routing: Audio in send, synth send -> FX. These are also modulation destinations.
- #231 Scrolling record, where you can easily keep the play head at the right distance from the rec head. [Shift] + [Record] forces scrolling recording.
- #1467 Sampling menu - Arm record: wait for midi clock start
- #1401 Sampling menu - Arm record: audio trigger level (LVL OFF: directly start recording)
- #438 Mod matrix - audio input follower
- #437 Resampling - now records to an auxiliary buffer and prompts the user to load, keep (store), or discard it after recording is done. 
- #1595 Sampling menu - "Channels": duplicate left (LL) or right channel (RR). Useful when using the GR-MEGA as an FX unit with mono sources.
- Op Encoder -> Crop recorded
- #1395 [Chord] + (Pitch) = without chord data: pitch snap to semitone, with chord data: or snap to chord keys 
- #1603 Grains close to record head won't crackle anymore.
- #1424 [Shift] + [Spray] toggles uni/bi 
- #1469 Sampling menu - popups when your press "init mono" or "init stereo"  
- [View] New sample view: overlapping time series "JointStencil"
- #1408 Tape and sampler engines now support spray polarity
- #1200 Physical modulation controls - holding down [LFO Select] and turning a destination knob now also works for all sources (dialed in using [Shift] + (Destination) encoder)
- New LFO wave graphics. square wave phase is more clear now.
- #1569 [View] + [Layer 1234] -> random waveform color, [Shift] + [View] + [Layer 1234] -> neutral waveform color
- #1398 File chooser preview - sample rate conversion for non-native sample rate. audition your 44.1, 88.2, 96, 192 kHz, etc samples in the right key.
- #1448 Sampling - Use an USB A audio interface as source.
- #1446 Sampling - name / status of USB A interface.
- [Feel] help bubbles in sampling menu
- [View] button now shows view mode in OSD
- (1.5.0-a8) window sides and window AM knobs now available for up front modulation with [LFO Select] button. 

changes:

- #1482 Better defaults for init patch: 0.1s attack and release, 1.0 Hz LFO's, pitch bend range 12 semitones, grain key trigger on
- #1444 Better/shorter recording text messages 
- More readable dialogs
- (1.5.0-a5) Menu button action now immediately switches from main screen to menu when button is pressed (not when released).
- #1594 Potentiometer pickups - setpoint range halved to avoid jumps when pot unlocks
- Buffered scrolling. boosts spectrogram frame rate, and frees up precious dsp time.
- #1475 Op encoder menu -> DRAG START/END now called SET START/END
- improved midi bpm estimation for delay fx
- #1628 (1.5.0-a5) sampling menu vu meters now use mean absolute instead of rms. better to estimate if you're in clipping territory this way.
- (1.5.0-a8) refuse to record in slice mode.

bugfixes:

- #1617 GR-1 patch import crash when playing, and proper matrix size
- #1635 (1.5.0-a3) large reverb could get muted by low time settings 
- Crop to tiny size + phase vocoder + (fft_len > cropped range) -> crash
- #1617, #1626 (1.5.0-a8) gr-1 patch import modulation fixes, sample rate conversion wrap crackle, sub-osc volume, random lfo frequency, delay time
- #1639 (1.5.0-a3) remove dead usb mountpoints when starting up
- #1620 Sampling menu - size can once again be set accurately in multiples of seconds or 10ms.
- #1616 Project menu -> [enter] on empty slot -> "load" -> gave a popup that was hard to close
- #1615 HPF resonance went up to 96% while LPF resonance tot 98% 
- Preset sample audition - plop when wrapping is now gone.
- (1.5.0-a1) Init preset in multitimbral killed layer LEDs
- System settings -> USB C Mode -> MIDI+FILES now has proper file sharing on tasty pi 5 / newer hardware
- (1.5.0-a4) Fixed a crash when recording into a buffer shorter than 40 ms. 
- (1.5.0-a4) A crash would immediately halt the pi. Now it restarts the app again.
- #1633 (1.5.0-a5) "ghost slices" existed after cropping, could lead to strange effects when using the play button.
- (1.5.0-a5) fixed bug where initially the LEDs didn't display the correct preset number. the first menu button press resulted in it thinking preset 1 was used.
- #1648 (1.5.0-a5) Multitimbral - focus op different layer + preset button - jumps to different preset 
- #1543 (1.5.0-a5) (FX Select), (FX1), (FX2), (FX Dry/Wet) - OSD uses official upper case fx names 
- #1628 (1.5.0-a5) sampling menu oscilloscope now has same level as main screen. 
- #1476 (1.5.0-a6) Fixed [Feel] button for layer volumes.
- #1437 (1.5.0-a6) Patch menu -> Env pile-up OFF.. could not handle a large amount of midi notes.  
- (1.5.0-a7) firmware update - robust against random enumeration of usb sticks!! 
- #1656 after loading a gr-1 performance, you could not load any project from the project menu.
- (1.5.0-a8) window (PowAR type) sides parameter modulation was broken since 1.4 

known issues:

- various MIDI CC's to still be implemented: glide, arp mode, scan mode, recording/sampling levels, window settings 
- high cpu load when connected to Macs via USB C, and using USB audio + MIDI + file sharing