[Production Verification] Logic Pro track-header fader and pan responsiveness

Support & Troubleshooting Logic Pro
1

As soon as I open metagrid on my ipad the track fader en pan knob will work once as it should and after that it only works in little parts. As soon as I move the mixer slider or pan knob it works again for one time and then again only in short bits.

MacBookPro Tahoe 26.6.1

Logic 12.3.1

Metaserver 6.1.3

Metagrid ipad 1.7.3. Build:35821

2

Hi Kris,

Thank you for posting this. Your email was received and a detailed response was sent there as well.

Your testing was extremely useful. Ruling out OmniSpace, the CC 7/10 configuration and the TCC resets pointed directly to MetaServer’s Logic Pro Accessibility handling.

MetaServer uses the Accessibility API to determine which part of Logic is active so MetaGrid Pro can switch pages automatically. While Track Header and Inspector controls are being dragged, Logic generates focus notifications very rapidly. MetaServer was responding with synchronous Accessibility reads, repeatedly interrupting Logic’s main thread and producing the stepped fader and pan movement you observed. Mixer controls do not generate the same notification pattern, which explains why they can behave differently.

MetaServer Mac 6.1.4 Beta 1 contains improvements for this issue:

  • Accessibility reads are suppressed while a mouse button is held.
  • Bursts of focus notifications are consolidated.
  • The cost of individual Accessibility reads has been substantially reduced.

Please install the beta while leaving Accessibility permission enabled and let us know how the Track Header and Inspector controls behave:

Download MetaServer Mac 6.1.4 Beta 1

Before installing it, one additional test would be very helpful: leave MetaServer running with Accessibility enabled, completely quit MetaGrid Pro on the iPad so that no device is connected, and then drag a Track Header fader.

Please let us know:

  1. Whether the fader becomes smooth when no iPad is connected.
  2. Whether you remember this working correctly with an earlier MetaServer version.

Either result will help confirm the exact boundary of the problem.

3

Ahhhhhh!!! This has been an issue for me since Logic 12.3! I thought I was going crazy! I only today tried to troubleshoot and disconnected the ipad from Metaserver then it started working as usual.

Happy to report that this 6.1.4 beta worked for me.

Thanks Przemek!

4

MetaServer Mac 6.1.4 is now publicly available and includes the Logic Pro Accessibility-performance correction developed from this report.

MetaServer now coalesces rapid focus notifications, defers synchronous Accessibility reads while a mouse button is held and limits the focus-ancestor traversal. This prevents repeated Accessibility queries from interrupting Logic’s main thread during Track Header and Inspector fader or pan drags.

Please update to MetaServer Mac 6.1.4, keep Accessibility permission enabled and test:

  1. A Track Header volume or pan drag with MetaGrid Pro connected.
  2. The same control with MetaGrid Pro disconnected but MetaServer still running.
  3. A Mixer fader for comparison.

Please let us know whether the Track Header and Inspector controls are now as smooth as the Mixer and whether Dynamic Focus Tracking still updates correctly after the drag ends.