Interpret dBFS, SNR, latency and distortion only within the route and processing settings shown in Evidence.
IP-AUD-01 / PCM LEVEL / DEVICE PATH
Acoustic Harmonic Distortion Experiment
Average multiple 1 kHz FFT frames with optional loopback floor calibration.
The audio path sounds distorted even below visible clipping.
This focused entry uses the shared Audio protocol. The measurement logic and Evidence version remain identical to the complete lab.
Remove the easiest false alarms first.
01
Close calls and recording apps, select the intended route and keep system gain fixed.
02
Use a moderate safe volume and avoid changing microphone distance during a protocol.
03
Treat acoustic and confirmed fixed-gain loopback sessions as different measurement paths.
Run one repeatable protocol.
- 01
Choose acoustic or confirmed fixed-gain loopback mode.
- 02
Capture the loopback floor, then average the 1 kHz signal frames.
- 03
Compare the fundamental with harmonics two through five.
Evidence the result should expose.
DIRECT / INFERREDFrame counts
DIRECT / INFERREDFloor calibration
DIRECT / INFERREDExperimental THD estimate
Separate observed, review and inconclusive.
Repeat with fixed gain, then compare wired, Bluetooth and direct loopback paths one variable at a time.
Acoustic measurements include speaker, room, microphone, OS and browser; they are not device specifications or hearing diagnoses.
Start with the likely path, then retest.
01
Acoustic path
02
Speaker/microphone clipping
03
Room reflection
04
Processing