🔍 Summary of the Issue:
After upgrading to Sonar 2025.07, clicking on audio or instrument tracks (just selecting them, not editing) during playback causes audio glitches, including:
Out-of-sync tempo-synced FX (e.g., MTremolo, MRhythmizer)
MIDI note dropouts (e.g., arp in Sylenth1 stops playing)
This did not occur in CbB (Cakewalk by BandLab) even under low buffer settings.
Glitches do not happen when clicking on clips or MIDI tracks.
Issue occurs in larger projects (~60 tracks, 20+ plugins), not in blank/test projects.
Tried: buffer size increase, plugin bridging changes, driver updates, all common settings (multiprocessing, MMCSS, plugin load balancing).
Audio interface: Focusrite Scarlett 6i6 Gen 2 (ASIO, latest driver).
Hardware and CPU usage are not bottlenecks.
🧠What Might Be Going On
1. GUI-to-Audio Thread Interference
Sonar may have introduced changes in how the track selection GUI action is handled — potentially interrupting real-time audio scheduling, especially in heavy projects.
Clicking on a track likely triggers focus changes, GUI refresh, and potentially UI-linked audio processing.
If this is handled poorly (e.g., synchronously or on the main thread), it can lead to audio glitches, especially with tempo-synced effects or note triggers.
2. VST Bridging Stability
Your use of multiple bridged 32-bit plugins (Shortcircuit) via JBridge may be playing a role. Even if they ran fine before, the host’s internal threading and resource management may now interact differently post-upgrade.
Clicking around the UI might be causing plugin thread contention or timing mismatches in the new host environment.
Bridged plugins (especially older 32-bit ones) are notoriously sensitive to such changes.
3. Project Size & Complexity
While your project isn't using heavy FX or CPU, the sheer number of VST instances and tracks might be pushing Sonar's real-time handling to a threshold, where any UI activity can cause minor timing disruptions.
4. Bug in Sonar 2025.07
Given this didn't happen in CbB and does happen reproducibly in Sonar 2025.07 (but not in minimal projects), this could be a regression or performance bug in the new version.
âś… What You Can Try Next
Here are focused suggestions you can try, and what to report if contacting Sonar/Cakewalk support:
🛠️ Technical Workarounds:
Disable Waveform Preview / Track Meter Animations Temporarily
These can tie into the GUI refresh and cause glitches.
Go to Preferences > Display and disable unnecessary visuals during playback.
Minimize GUI Load
Try switching to the Console View or a different layout that doesn’t actively draw 60+ tracks at once.
Keep fewer views open (e.g., close Inspector, Browser, etc.) during playback.
Try Running Sonar as Administrator
Helps avoid OS-level priority mismatches, particularly with MMCSS.
Create a Copy of the Project Without Bridged Plugins
Replace or remove the Shortcircuit instances just for testing.
See if the issue persists with native VSTs only.
Set “ThreadSchedulingModel” to 2 (if editable via INI/config)
In some older Cakewalk/SONAR versions, you could tweak thread scheduling via AUD.INI.
May not exist in Sonar 2025, but worth checking for advanced options.
Try Disabling Tempo Sync on Melda FX (if possible)
Just to test: if MTremolo or MRhythmizer has a non-tempo mode, see if the glitch is less severe. This would confirm the clock resync glitch as a root issue.
📬 When Reporting to Cakewalk Support:
Provide:
Repro steps: "Clicking on track number during playback in large project causes glitch."
Mention plugins involved (especially tempo-synced Melda FX and bridged Shortcircuit).
Attach project file (or a stripped-down repro version).
Link to the audio examples (like your rec1 and sine files).
Confirm that CbB 2019.09 did not have this issue under identical conditions.
🧩 Final Thoughts:
Unfortunately, this seems like a low-level timing bug or performance regression in Sonar 2025, likely affecting how UI thread interactions impact audio thread timing. It may be worse in larger projects or when bridged plugins are involved.
If it's a dealbreaker and you can't find a stable workaround, you might consider:
Keeping CbB around for critical mixing tasks
Using Reaper or another lightweight host just for playback and final bounces (many users offload this way)
https://audiobookcalcualtor.us/
🔍 Summary of the Issue: After upgrading to Sonar 2025.07, clicking on audio or instrument tracks (just selecting them, not editing) during playback causes audio glitches, including: Out-of-sync tempo-synced FX (e.g., MTremolo, MRhythmizer) MIDI note dropouts (e.g., arp in Sylenth1 stops playing) This did not occur in CbB (Cakewalk by BandLab) even under low buffer settings. Glitches do not happen when clicking on clips or MIDI tracks. Issue occurs in larger projects (~60 tracks, 20+ plugins), not in blank/test projects. Tried: buffer size increase, plugin bridging changes, driver updates, all common settings (multiprocessing, MMCSS, plugin load balancing). Audio interface: Focusrite Scarlett 6i6 Gen 2 (ASIO, latest driver). Hardware and CPU usage are not bottlenecks. 🧠What Might Be Going On 1. GUI-to-Audio Thread Interference Sonar may have introduced changes in how the track selection GUI action is handled — potentially interrupting real-time audio scheduling, especially in heavy projects. Clicking on a track likely triggers focus changes, GUI refresh, and potentially UI-linked audio processing. If this is handled poorly (e.g., synchronously or on the main thread), it can lead to audio glitches, especially with tempo-synced effects or note triggers. 2. VST Bridging Stability Your use of multiple bridged 32-bit plugins (Shortcircuit) via JBridge may be playing a role. Even if they ran fine before, the host’s internal threading and resource management may now interact differently post-upgrade. Clicking around the UI might be causing plugin thread contention or timing mismatches in the new host environment. Bridged plugins (especially older 32-bit ones) are notoriously sensitive to such changes. 3. Project Size & Complexity While your project isn't using heavy FX or CPU, the sheer number of VST instances and tracks might be pushing Sonar's real-time handling to a threshold, where any UI activity can cause minor timing disruptions. 4. Bug in Sonar 2025.07 Given this didn't happen in CbB and does happen reproducibly in Sonar 2025.07 (but not in minimal projects), this could be a regression or performance bug in the new version. ✅ What You Can Try Next Here are focused suggestions you can try, and what to report if contacting Sonar/Cakewalk support: 🛠️ Technical Workarounds: Disable Waveform Preview / Track Meter Animations Temporarily These can tie into the GUI refresh and cause glitches. Go to Preferences > Display and disable unnecessary visuals during playback. Minimize GUI Load Try switching to the Console View or a different layout that doesn’t actively draw 60+ tracks at once. Keep fewer views open (e.g., close Inspector, Browser, etc.) during playback. Try Running Sonar as Administrator Helps avoid OS-level priority mismatches, particularly with MMCSS. Create a Copy of the Project Without Bridged Plugins Replace or remove the Shortcircuit instances just for testing. See if the issue persists with native VSTs only. Set “ThreadSchedulingModel” to 2 (if editable via INI/config) In some older Cakewalk/SONAR versions, you could tweak thread scheduling via AUD.INI. May not exist in Sonar 2025, but worth checking for advanced options. Try Disabling Tempo Sync on Melda FX (if possible) Just to test: if MTremolo or MRhythmizer has a non-tempo mode, see if the glitch is less severe. This would confirm the clock resync glitch as a root issue. 📬 When Reporting to Cakewalk Support: Provide: Repro steps: "Clicking on track number during playback in large project causes glitch." Mention plugins involved (especially tempo-synced Melda FX and bridged Shortcircuit). Attach project file (or a stripped-down repro version). Link to the audio examples (like your rec1 and sine files). Confirm that CbB 2019.09 did not have this issue under identical conditions. 🧩 Final Thoughts: Unfortunately, this seems like a low-level timing bug or performance regression in Sonar 2025, likely affecting how UI thread interactions impact audio thread timing. It may be worse in larger projects or when bridged plugins are involved. If it's a dealbreaker and you can't find a stable workaround, you might consider: Keeping CbB around for critical mixing tasks Using Reaper or another lightweight host just for playback and final bounces (many users offload this way) https://audiobookcalcualtor.us/