Source Playback Architecture
Map every media, transport, control, clock, conversion, routing, and analog stage.
Sources And Mobile Audio
A Source Is A Path, Not A Logo
A phone, head unit, USB port, Bluetooth badge, streaming app, or projection screen describes only part of the playback system. The maintained source workflow traces media, software, transport, host, decoder, sample-rate conversion, volume, mixing, DAC, analog output, and the next input boundary.
Open the guided Head Units, Smartphone Audio, And Source Verification lesson →
Canonical Topics
Head-Unit Preamp Output
Measure clean voltage, noise, impedance, channel behavior, and next-stage compatibility.
Volume Control And Level State
Record phone, app, host, head-unit, DSP, normalization, mute, and ducking states.
Bluetooth Classic Audio
Separate A2DP, AVRCP, HFP, codec negotiation, buffering, and measured behavior.
Bluetooth LE Audio
Understand LC3, isochronous transport, unicast, multi-stream, broadcast, and support layers.
USB Audio Playback
Separate connector, power, host/device role, storage, projection, and Audio Class streaming.
Smartphone Projection Audio
Map CarPlay and Android Auto media, calls, navigation, controls, transport, and host behavior.
Source Priority And Audio Focus
Verify pause, replace, duck, mix, mute, restore, safety, and multi-zone behavior.
Measurement Contract
- Use one known reference file or signal for cross-source comparisons.
- Record phone, app, operating system, host, firmware, transport, source mode, and every volume state.
- Measure clean maximum level, response, noise, latency, channel map, and clipping for each source.
- Trigger calls, navigation, assistants, alerts, reconnects, key cycles, and sleep.
- Save the approved calibration and user-volume states per source.