Subject: Bug Report: Scaler 3.4 (AU Multi-Output) in Logic Pro – Mixer Output Selector Ignored (Routes Everything to Main Track)

[jonkenhod]

Hi Scaler Support Team,

I am experiencing a multi-output routing bug in Scaler 3 (version 3.4, AU Multi-Output 9x Stereo) in Logic Pro on macOS.

Issue Description:
Inside Scaler 3’s Mixer, the track output assignment dropdown is completely ignored by the Audio Unit audio engine. Regardless of whether a track is set to Channel 1, Channel 2 (or higher), or None, all audio continues to output directly through the main Scaler instance track in Logic Pro, leaving all multi-output Aux tracks completely silent.

Steps to Reproduce:

1. Load Scaler 3 v3.4 (Multi-Output 9x Stereo) on a Software Instrument track in Logic Pro.
2. Create the multi-output Aux channel strips in Logic’s Mixer (+ button).
3. Load two tracks with active patterns/instruments inside Scaler 3.
4. Set both tracks to Channel 1 in Scaler 3’s Mixer — both play through the main Scaler track in Logic.
5. Switch both tracks in Scaler 3’s Mixer to Channel 2 — both tracks continue outputting through the main Scaler instance track, and the Aux track stays silent.
6. Switch the tracks in Scaler 3’s Mixer to None — audio still continues outputting through the main Scaler instance track in Logic.

System Details:

• Plugin: Scaler 3 (v3.4, Audio Unit – Multi-Output 9x Stereo)
• DAW: Logic Pro 13
• OS: macOS Tahoe 26.7.2

Could you please confirm if this is a known bug in v3.4 and when a fix will be available?

Thanks,
John

[davide]

Hi @jonkenhod Welcome to the forum,
Scaler doesn’t output multi-channel audio. You would just route each Scaler Track’s MIDI Output to another Instrument channel in Logic to do what I think you want.
Check this section in this video for an explanation. Basically you just send each channel out from Scaler to whatever MIDI channel you want. Then you set your receiving instrument in Logic to receive from Internal MIDI In (Select Instrument Output /Scaler / The required MIDI channel).

Building a Track from Scratch with Scaler 3 & MIDI Out – Full Walkthrough

See attached here for my receiving channel: