Comment 23 for bug 900364

I tried a possible workaround by Slaker96 in post #22 today. It did not work for me. However, in the process of trying the workaround I came across something that may get us closer to understanding the nature of this bug.

To operate Mixxx 1.11.0 on my laptop, I use an external USB audio card (Sabrent USB-SND8 Sound Card - 8 Channel 3D, 7.1 Surround Sound, USB 2.0, S-PDIF In/Out). Here is my audio config:

> aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC269VC Analog [ALC269VC Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 0: PCH [HDA Intel PCH], device 3: HDMI 0 [HDMI 0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Device [USB Sound Device], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

> arecord -l
**** List of CAPTURE Hardware Devices ****
card 0: PCH [HDA Intel PCH], device 0: ALC269VC Analog [ALC269VC Analog]
  Subdevices: 1/1
  Subdevice #0: subdevice #0
card 1: Device [USB Sound Device], device 0: USB Audio [USB Audio]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

In the Mixxx config:
Master Output is "USB Sound Device: USB Audio (hw:1.0)" (external audio card)
Headphones Output is "HDA Intel PCH: ALC269VC Analog (hw:0,0)" (internal audio card)
Microphone Input is "HDA Intel PCH: ALC269VC Analog (hw:0,0)" (internal audio card)

With this setup, microphone sound is indeed horrible as observed earlier by many. Now, set "Headphones Output" to "None". The microphone sound is good. Set the headphones output back to "HDA Intel PCH" and the microphone sound is again very bad.

When I set the microphone input to "USB Sound Device" and re-connect the mic to the external audio card, the microphone sound is again horrible.

It looks like the microphone sound is bad whenever the same hardware device is used as output for either the master audio or the headphones.

Any comments, Mixxx gurus?