Keep the phone in the audio-path description
Roku’s mobile Headphone Mode routes listening through the phone app. Roku documents an Adjust audio delay procedure there. A subtitle offset in the viewing app addresses a different element and is not a substitute for output synchronization.
Write down the Roku, phone and headphones involved. Changing from wired phone headphones to a Bluetooth pair changes part of the route and deserves its own observation.
Use the documented wizard
In the Roku mobile app, open Remote, enable Headphone Mode, open the control settings and choose Adjust audio delay. Follow the on-screen process. Roku also documents an advanced adjustment if the initial procedure leaves a mismatch.
Keep a familiar dialogue passage for checking afterwards. Do not change TV processing or another app offset during the same comparison.
Distinguish a stable offset from interruptions
Consistently early or late sound and irregular dropouts are different symptoms. An offset adjustment can be a useful response to the former without proving the route is reliable under the latter.
For support, report the listening method, phone/headphone combination and whether the wizard changed the result. This page explains Roku’s documented tool without claiming a measured timing result on your hardware.
Questions answered
Is app subtitle delay the same correction?
No. Subtitle timing and headphone audio output timing are different layers.
Does a successful delay adjustment prove there are no wireless dropouts?
No. Stable timing and connection continuity need separate observations.
Sources & further reading
Official references for the subjects discussed. Service terms and device software can change.