MIDI Latency Issue with Scaler 2 & Scaler 3 as MIDI FX in Logic Pro 11 /12 (Specific to Apple Studio Instruments)

Scaler 2 Support Bug Reports
1

I am writing to report a persistent MIDI latency issue I am experiencing with both Scaler 2 and Scaler 3 while using them as MIDI FX plugins in Logic Pro.

The Issue: When Scaler (2 or 3) is placed in the MIDI FX slot to c

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ontrol Apple’s “Studio” series instruments (such as Studio Horns or Studio Cellos), there is a significant delay/lag between the key press and the actual sound output. This issue does not occur when using simple stock instruments like the “Classic Electric Piano”.

Troubleshooting already performed:

  1. Scaler Settings: I have disabled DAW Sync, Play Quantize, and set Input Quantize to OFF. I also ensured Bind MIDI is not forcing a “Next Beat” trigger.

  2. Logic Pro Settings: I am using a low I/O Buffer Size and have “Low Latency Monitoring Mode” active. I have also tested different Latency Compensation settings.

  3. Instrument specific: I have disabled “Legato Transitions” and “Auto Voice Split” within the Studio Instruments to rule out internal script processing lag.

Observation: The lag is only present when Scaler is used in the MIDI FX slot. If I load Scaler as a Software Instrument and route the MIDI, it works perfectly. This suggests a synchronization conflict between the MIDI FX engine and the high-buffer requirements of Apple’s multi-sampled Studio instruments.

System Specs:

  • DAW: Logic Pro (Latest version)

  • Plugins: Scaler 2 & Scaler 3 (AU MIDI FX)

  • OS: macOS [Tu versión aquí]

Could you please advise if there is a workaround or a fix planned for this specific MIDI FX behavior?

Best regards, julian

2

Hi @Julian I have the same setup and just checked and get 0 delay. Have you tried another third party or even Logic MIDI FX as a process of elimination?