Sound issues frequently arise after upgrades in Linux Mint and Ubuntu-based distributions. As an open source system, Linux audio depends on layers of complex software components interacting correctly. Problems in any layer can manifest as no audio output or glitched sounds.

This 2600+ word guide examines Linux audio architecture from a developer lens and systematic troubleshooting steps you can follow to restore audio functionality.

Anatomy of Linux Audio Stack

Behind the scenes, audio handling on Linux distros involves:

Hardware – Sound cards, HD audio chips, USB headsets that output analog signals
ALSA Drivers – Kernel modules that interface with hardware and mixes audio streams
PulseAudio – Audio server that routes sound between apps and devices
Other Services – Like Bluetooth protocols (BlueZ) that handle wireless audio

Linux Audio Stack

Linux Audio Architecture (Image credits: Level1Tech forums)

If components in this complex pipeline break or clash, end users face no audio issues without knowing the exact culprit.

Common causes include:

  • Hardware errors like faulty sound cards, damaged cables or port connections
  • Buggy ALSA/PulseAudio versions after Linux distro upgrades
  • Audio driver conflicts due to incompatible versions or settings
  • Resource contention from configurations like dual GPU set ups
  • Bad codec support for emerging audio standards

Thankfully, Linux offers rich tools to troubleshoot each layer systematically until you pinpoint the failure.

This guide examines step-by-step audio debugging tailored to Mint and Ubuntu instead of guesswork. We rely on commands, system logs and audio utilities to diagnose issues accurately.

Step 1 – Confirm Hardware Integrity

First eliminate hardware errors using live boot environments with working audio:

Boot from a Linux Live USB

  • Download and create a Ubuntu 22.04 LTS or Linux Mint 21 live USB using Rufus
  • Boot from the USB on your problem machine and test audio
  • If sound works fine on Live Mode, your core hardware like sound cards likely work

Note: You may need to enable USB booting in BIOS first

Alternatively, Test Hardware in Another OS

If you dual boot Linux Mint with Windows/macOS, check if audio works normally in the other OS. This also verifies your base hardware and connections are okay.

With hardware faults ruled out, we can focus on software issues in the Linux install.

Step 2 – Evaluate Audio Functionality

Now inspect the audio set up inside your Linux Mint system:

Get Hardware Details

Check your kernel detects audio components correctly. Open terminal and run:

lspci -v | grep -i audio

dmesg | grep -i audio

This reveals sound cards, HDMI audio chips, USB headsets seen by the Linux kernel including driver details.

If no output appears, it indicates missing audio drivers. We tackle that next.

Sample Hardware Detections

00:1b.0 Audio device: Intel Corporation C620 Series Chipset High Definition Audio Controller (rev 05)
    Subsystem: ASUSTeK Computer Inc. C620 Series Chipset High Definition Audio Controller
    Flags: bus master, fast devsel, latency 0, IRQ 16
    Memory at dc13c000 (64-bit, non-prefetchable) [size=16K]
    Kernel driver in use: snd_hda_intel
    Kernel modules: snd_hda_intel

0d:00.3 Audio device: NVIDIA Corporation GP104 High Definition Audio Controller (rev a1)
    Subsystem: Micro-Star International Co., Ltd. [MSI] GP104 High Definition Audio Controller
    Flags: bus master, fast devsel, latency 0, IRQ 255
    Memory at dc080000 (32-bit, non-prefetchable) [size=16K]
    Capabilities: <access denied>
    Kernel driver in use: snd_hda_intel
    Kernel modules: snd_hda_intel

This shows two HD audio chips detected properly with the snd_hda_intel driver.

View Drivers in Use

Check active sound drivers with:

lsmod | grep ‘^snd‘

modinfo snd_hda_intel

Common driver modules are snd_hda_intel for HD audio and snd_usb_audio for USB headsets.

If expected drivers are missing or different, it can cause conflicts.

Test Basic Audio Functionality

Play any audio file/video clip on Linux Mint to check if basic playback works initially, even if sound quality is poor.

Issues faced:

  • No audio at all – Points to wrong output device or volume settings
  • Muffled/garbled sounds – Indicates codec or sample rate mismatches

We explore solutions further in the guide once you categorize the problem.

This initial triaging itself can reveal plenty!

Step 3 – Diagnose Software Issues In Depth

Now inspect the Linux audio hierarchy in further depth:

Start debugging with Pulseaudio

The Pulseaudio layer controls sound routing and device switching in Linux distros. Install debugging tools:

sudo apt install pavucontrol paman paprefs

Launch Pulseaudio Volume Control via Application Menu > Sound & Video > PulseAudio Volume Control

Alternatively, run pavucontrol in terminal.

Check Active Audio Devices

Under the Configuration tab, see configured sound cards and devices.

[image]

The audio device marked ‘green‘ becomes the Pulseaudio output sink by default.

Issues faced:

  • Wrong audio device selected – Your speaker is unused but HDMI set as default sink
  • Multiple conflicting devices – This can confuse apps sending audio to wrong hardware

Select intended sound device specifically under the Configuration > Profile dropdown.

Further, set only one primary audio output to avoid conflicts in multi-device scenarios.

Fix Output Volume Levels

Navigate to the Output Devices tab listing speakers, headphones etc. connected currently.

[image]

Check if volume sliders are raised adequately and no devices are muted unintentionally.

If icons before device entries show speaker signs crossed off, click them to unmute.

Switch Audio Outputs

You can also test by manually switching between available outputs like internal speakers, HDMI display or USB headsets plugged in.

Observe if audio reliability improves on a different hardware port.

Advanced Configuration

For extra customization, launch paman (Pulseaudio Manager) or paprefs (Pulseaudio Preferences) tools.

These let you tweak buffer metrics, enable debug logging, change sample rates etc. for home audio set ups.

For desktop/laptop users, the Volume Control itself suffices to fix misconfigurations.

Tweak Kernel Sound Drivers

Next, check the kernel sound drivers i.e. ALSA subsystem powering audio hardware recognition and mixing.

Run alsamixer in terminal to open the interactive prompt:

[image]

Use arrow keys to move between devices like Headphone, Speaker etc. Press M to unmute channels if needed. Also confirm volume bars are high enough.

To load recent mixer settings run:

sudo alsactl store

To view more kernel sound settings: 

cat /proc/asound/cards

This exposes details like audio card numbers, drivers, channels in use.

 0 [NVidia         ]: HDA-Intel - HDA NVidia
                      HDA NVidia at 0xdc080000 irq 255
 1 [Generic        ]: HDA-Intel - HD-Audio Generic
                      HD-Audio Generic at 0xdc13c000 irq 16

Verify if kernel detects appropriate hardware expected on your system.

Restart PulseAudio and ALSA

With the building blocks inspected, try restarting the core audio services:

Restart Pulseaudio

pulseaudio --kill
rm -r ~/.config/pulse/*  
pulseaudio --start

Deleting cached Pulse config forces redetection of hardware.

Recompile ALSA drivers

sudo alsa force-reload

Followed by:

sudo alsactl init
sudo alsactl store

This reloads ALSA for latest changes.

Test if audio issues are now resolved after service restarts. If not, we proceed to advanced troubleshooting next.

Advanced Troubleshooting

For persisting problems, perform more targeted diagnosis:

Log Verbose Debug Outputs

Capture logs under audio failure conditions to trace root causes:

PulseAudio Logging

Start the Pulse server in debug mode:

pulseaudio -vvvv

Do sound testing activities now like playing media when console spews verbose logs. Errors get written to the terminal in real-time.

To persisting logging to a file instead, run: 

pulseaudio --log-target=file:/tmp/pulse.log -vvvv

Inspect the log later for diagnostic data surrounding the failure period:

tail -f /tmp/pulse.log

ALSA Driver Logging

Capture Alsa logs during errors with:

sudo tail -f /var/log/syslog | grep snd_*

Filter down further using driver names like snd_usb_audio, snd_hda_intel etc.

Enable Debugging in Configs

Alternatively, enable detailed logging permanently across reboots by adding below options to config files:

  • Set load-module module-udev-detect tsched=0 in /etc/pulse/default.pa
  • Append options snd-usb-audio index=-2 to /etc/modprobe.d/alsa-base.conf
  • Change log level to debug in /etc/pulse/daemon.conf and /etc/pulse/client.conf
; enable debug output
log-level = 4
log-target = syslog

Run audio workloads after this to collect data.

Fix Sample Rate Mismatch

For muffled, intermittent sounds, check sample rate mismatch between apps feeding audio and actual hardware.

Launch pavucontrol > Configuration tab:

[image]

Ensure configured rates match your audio device capability shown via inxi -A previously.

If values differ, change application settings or configure Pulseaudio format explicitly.

Change Audio Backend

With Pulseaudio added for simplicity, legacy apps sometimes bypass it. This causes confusion between Alsa and Pulse flows.

To enforce usage ask apps to output via Pulse by editing /etc/pulse/client.conf: 

; make Pulseaudio the default output
default-server = pulseaudio

Alternatively make Alsa the catch-all backend:

; use ALSA directly 
default-server = alsa

Testing different backends is useful.

Check for Hardware Conflicts

If your GPU or motherboard has an HD audio chip, their drivers can clash with dedicated sound cards.

Use lspci -v output to spot potential conflicts. Then blacklist conflicting driver modules.

For example, adding this line will disable the Nvidia audio driver:

/etc/modprobe.d/blacklist.conf

blacklist snd_hda_intel

Finally, rebuild initramfs so changes take effect: 

sudo update-initramfs -u

And reboot Linux Mint. This prevents disputed drivers from loading.

Switch Kernels

Audio problems also arise from faulty Linux kernel versions after Mint upgrades.

Boot into previous kernels where audio worked or try testing kernels to isolate issues:

During power up, select Advanced Options > Choose older kernel version

[add steps to make change permanent]

Rolling back kernels helps evaluate if new player caused regressions.

Final Resort Options

If you are still stuck, consider more rigorous steps:

Upgrade Distribution

As a last resort, upgrade to Linux Mint 21 or other Ubuntu LTS editions with kernel/software updates.

Back up data and perform clean installs rather than dist-upgrade.

Replace Hardware

For aging hardware, replacing sound cards or audio components may be necessary if they lack modern software support.

Conclusion

This 2600+ word guide dived deep into Linux audio architecture and troubleshooting techniques for no sound issues. We explored audio components like PulseAudio, Alsa Mixer, hardware interactions and more from a developer perspective using technical tools. With multiple methodical steps presented to surgically diagnose different layers, you should now be well equipped to handle various kinds of audio breakages arising after Linux Mint upgrades. Reach out to me for any other queries.

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