Troubleshooting: no sound in videos22.09.26

# Troubleshooting: no sound in videos (PC audio, 2026-09-22)

Headset plugged in, works on another computer. No sound on this PC.
Here is the step-by-step check — what to run, in order, and what each result means.

## Step 1 — Is the hardware even there?

```bash
cat /proc/asound/cards
```

Output:
```
 0 [NVidia         ]: HDA-Intel - HDA NVidia      <- GPU, HDMI only
 1 [Generic        ]: HDA-Intel - HD-Audio Generic <- onboard analog (headset jack)
```

Meaning: both cards are present → hardware is detected, don't blame the cable/port yet.
(No USB audio entry here → this headset is a 3.5mm jack, going to card 1.)

## Step 2 — Which playback devices exist?

```bash
aplay -l
```

Output:
```
card 0: NVidia ... HDMI 0 / HDMI 1 / HDMI 2 / HDMI 3   <- monitor/TV outputs
card 1: Generic [HD-Audio Generic], device 0: ALC897 Analog   <- our headset jack
```

Meaning: `hw:1,0` = `ALC897 Analog` is present. ALSA layer is fine.
It's now a *sound-server routing* problem, not hardware.

## Step 3 — What is the current default output (sink)?

```bash
pactl info | grep -i default
```

Output:
```
Default Sink: alsa_output.pci-0000_01_00.1.hdmi-stereo   <- BAD: HDMI/monitor
```

Meaning: the system default is the HDMI output (GPU/monitor), not the headset.
Videos go to the monitor's output → no sound on earphones.

## Step 4 — List all sinks and their state

```bash
pactl list sinks short
```

Output:
```
15  alsa_output.pci-0000_01_00.1.hdmi-stereo        RUNNING   <- default, from card 0
17  alsa_output.pci-0000_72_00.6.analog-stereo      IDLE      <- headset jack, unused
```

Meaning:
- `RUNNING` = audio is actively flowing there (the HDMI sink).
- `IDLE` = available and working, but nothing is routed to it (the headset sink).

This is the smoking gun: right sink exists, wrong sink selected.

## Step 5 — Verify by switching the default

```bash
pactl set-default-sink alsa_output.pci-0000_72_00.6.analog-stereo
speaker-test -c 2 -t sine -l 1     # plays a tone on L/R channels; Ctrl+C to stop
```

Meaning: sound now comes out of the headset → confirmed diagnosis.

## Step 6 — Make it permanent (survive reboot)

```bash
echo "set-default-sink alsa_output.pci-0000_72_00.6.analog-stereo" | sudo tee -a /etc/pulse/default.pa
```

## Vocabulary (so the steps stay understandable)

| Term | Meaning |
|---|---|
| **card** | physical audio device (e.g. onboard `ALC897`, Nvidia HDMI) |
| **sink** | an output that sound can be routed to (headset jack, HDMI) |
| **default sink** | where system sound goes when an app doesn't choose one |
| **RUNNING / IDLE** | is audio flowing / available-but-silent |
| `alsa_output.pci-XXXX.analog-stereo` | PulseAudio name of the onboard headset output |

Anonymous

Troubleshooting: no sound in videos22.09.26

Information Epoch 1790201046