[Created at pci.366]
 Unique ID: u1Nb.WiEkMfkoYv9
 SysFS ID: /devices/pci0000:00/0000:00:1b.0
 SysFS BusID: 0000:00:1b.0
 Hardware Class: sound
 Model: "Intel 5 Series/3400 Series Chipset High Definition Audio"
 Vendor: pci 0x8086 "Intel Corporation"
 Device: pci 0x3b56 "5 Series/3400 Series Chipset High Definition Audio"
 SubVendor: pci 0x17aa "Lenovo"
 SubDevice: pci 0x215e 
 Revision: 0x06
 Driver: "snd_hda_intel"
 Driver Modules: "snd_hda_intel"
 Memory Range: 0xf0900000-0xf0903fff (rw,non-prefetchable)
 IRQ: 25 (701 events)
 Module Alias: "pci:v00008086d00003B56sv000017AAsd0000215Ebc04sc03i00"
 Driver Info #0:
   Driver Status: snd_hda_intel is active
   Driver Activation Cmd: "modprobe snd_hda_intel"
 Config Status: cfg=new, avail=yes, need=no, active=unknown

What is it I need to fix and how?

I checked your suggestions on: https://support.mozilla.org/en-US/kb/fix-common-audio-and-video-issues but when I click on a link apparently pointing to: https://www.pulseaudio.org/ but I am being redirected to an obnoxious looking page at: http://0pointer.net/ ~ The problem doesn't seem to be the sound card since you listen through it just fine. Here is what I have got: $ hwinfo --sound 10: PCI 1b.0: 0403 Audio device [Created at pci.366] Unique ID: u1Nb.WiEkMfkoYv9 SysFS ID: /devices/pci0000:00/0000:00:1b.0 SysFS BusID: 0000:00:1b.0 Hardware Class: sound Model: "Intel 5 Series/3400 Series Chipset High Definition Audio" Vendor: pci 0x8086 "Intel Corporation" Device: pci 0x3b56 "5 Series/3400 Series Chipset High Definition Audio" SubVendor: pci 0x17aa "Lenovo" SubDevice: pci 0x215e Revision: 0x06 Driver: "snd_hda_intel" Driver Modules: "snd_hda_intel" Memory Range: 0xf0900000-0xf0903fff (rw,non-prefetchable) IRQ: 25 (701 events) Module Alias: "pci:v00008086d00003B56sv000017AAsd0000215Ebc04sc03i00" Driver Info #0: Driver Status: snd_hda_intel is active Driver Activation Cmd: "modprobe snd_hda_intel" Config Status: cfg=new, avail=yes, need=no, active=unknown ~ What is it I need to fix and how?