Engineering guides / AI and realtime voice integration
By Arte Soft engineering · 24 October 2026
iOS audio session routing: repair silent microphones and missing playback
Microphone permission can be granted while an application still captures nothing. Diagnose the active audio session, selected route and running graph separately from the remote speech service; the permission dialog proves only one part of the chain.
Observe the route at the point of failure
Log the selected input and output, engine state, channel format and session activation result when capture starts. Compare these with a working launch. Do not rely on the route shown several seconds earlier in a settings screen. A Bluetooth accessory, phone interruption or competing playback component may have changed the effective configuration between the user’s tap and the first microphone sample.
Assign ownership of session configuration
Identify every component that changes the shared audio session. Recording, realtime transport, speech synthesis and preview playback may all attempt to choose categories or modes. Consolidate the policy so the last component to initialize does not silently override the rest. A routing repair often involves lifecycle coordination rather than a completely new audio library or a new permission request.
Rebuild only what has become invalid
Route changes can affect sample rate, channel count and node connections. Define which parts of the graph must be recreated and which state should survive. Preserve the user’s chosen conversation mode while resetting unusable buffers. Handle failed activation visibly and allow a clean retry. Repeatedly restarting the entire session without explaining the cause can consume requests while never restoring capture.
Cover interruptions and transitions
Test an incoming call interruption, background and foreground transitions, headset removal and repeated start-stop cycles. Include the receiver, built-in speaker and accessories the product claims to support. Record whether capture resumes automatically or requires an explicit tap. Either policy can be valid when communicated clearly, but silent ambiguity leaves the user believing that the application is recording when it is not.
Define a diagnostic handover
Useful artifacts include an audio ownership diagram, route event logs, a minimal reproduction and a device checklist. For privacy, capture levels and state changes may be sufficient; full conversation recordings need a separate reason. Acceptance should verify that samples reach the intended processor, responses play through the expected route and the next session starts without reinstalling the app.
Audio-routing reproduction notes
- Write down which accessory was connected before launch, which route was selected after Start and whether input samples actually arrived.
- Capture the session activation error if present instead of assuming a granted permission proves the graph started.
- After fixing the transition, verify the next clean start without reinstalling or clearing the user’s data, since those actions can conceal lifecycle defects.
Understand the boundary of the fix
An audio session audit cannot prove a remote model understands speech, and a successful text response cannot prove microphone routing works. Validate those stages independently. Arte Soft can discuss this work through the published GPT Realtime Assistant product. Bring the affected OS and hardware versions plus a short reproduction sequence, so the engagement can target the failing transition instead of guessing from a screenshot of a microphone icon.
Relevant Arte Soft work
GPT Realtime Assistant — our own published product is our own product or engineering project. It provides context for the work we discuss here; it is not a claim of identical results for every client deployment.
Sources and further reading
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