Comment # 15 on bug 1157910 from Freek de Kruijf

I reopened this problem because I hear the same strange sound when I play a
video in Firefox and again, testing Musescore, it also produces the strange
sound.

So it looks like there is a problem in the sound system.

In both cases I hear the sound distorted with noise, but also the same sound
distorted with noise delayed about 1 second again. When I stop playing the
sound, the delayed sound continues to play and stops playing after this second.

# hwinfo --sound
10: PCI 500.1: 0403 Audio device                                
  [Created at pci.386]
  Unique ID: 5yAR.K3+3qP5NfZ8
  Parent ID: _Znp.ZJmKoWxd6BF
  SysFS ID: /devices/pci0000:00/0000:00:02.0/0000:05:00.1
  SysFS BusID: 0000:05:00.1
  Hardware Class: sound
  Model: "ATI Cedar HDMI Audio [Radeon HD 5400/6300/7300 Series]"
  Vendor: pci 0x1002 "ATI Technologies Inc"
  Device: pci 0xaa68 "Cedar HDMI Audio [Radeon HD 5400/6300/7300 Series]"
  SubVendor: pci 0x1043 "ASUSTeK Computer Inc."
  SubDevice: pci 0xaa68 
  Driver: "snd_hda_intel"
  Driver Modules: "snd_hda_intel"
  Memory Range: 0xfe9bc000-0xfe9bffff (rw,non-prefetchable)
  IRQ: 36 (177 events)
  Module Alias: "pci:v00001002d0000AA68sv00001043sd0000AA68bc04sc03i00"
  Driver Info #0:
    Driver Status: snd_hda_intel is active
    Driver Activation Cmd: "modprobe snd_hda_intel"
  Config Status: cfg=yes, avail=yes, need=no, active=unknown
  Attached to: #32 (PCI bridge)

29: PCI 14.2: 0403 Audio device
  [Created at pci.386]
  Unique ID: 5Dex.BDUuYMOWyw7
  SysFS ID: /devices/pci0000:00/0000:00:14.2
  SysFS BusID: 0000:00:14.2
  Hardware Class: sound
  Model: "ATI SBx00 Azalia (Intel HDA)"
  Vendor: pci 0x1002 "ATI Technologies Inc"
  Device: pci 0x4383 "SBx00 Azalia (Intel HDA)"
  SubVendor: pci 0x1002 "ATI Technologies Inc"
  SubDevice: pci 0x4383 
  Revision: 0x40
  Memory Range: 0xfe6f8000-0xfe6fbfff (rw,non-prefetchable)
  IRQ: 10 (no events)
  Module Alias: "pci:v00001002d00004383sv00001002sd00004383bc04sc03i00"
  Driver Info #0:
    Driver Status: snd_hda_intel is active
    Driver Activation Cmd: "modprobe snd_hda_intel"
  Config Status: cfg=yes, avail=yes, need=no, active=unknown

Clicking on the loudspeaker symbol in the system tray, shows two devices:
HDMI/DisplayPort/Cedar ... and
Simultanious output to Ce...

It is quite possible sound is back to normal later during this KDE session or
after a restart.

Will report my further findings.