[ubuntu-studio-users] Weird - Same hardware, different kernels, different levels of background noise

[Kaj Ailomaa]

On Mon, Jun 8, 2015, at 09:37 PM, MusicFan wrote:
> Hi,
> 
> I am aware that my systems are not Ubuntu studio systems, nonetheless, I
> am hoping that you might have some suggestions on what steps to take in
> order to identify the root cause for the difference in background noise.
> 
> The problem is the following: recording voice with Audacity using a USB
> headset (Logitech PC Headset 960 USB).
> Recording the voice with an older kernel generates very little background
> noise (which is easy to remove with Audacity). The noise is hardly
> noticeable.
> Recording the voice with a newer kernel generates a lot of background
> noise (removing it with Audacity removes part of the voice as well).
> 
> The hardware is same, as well as the recording environment. 
> Older Linux is:
>  System:    Kernel 3.2.0-84-generic x86_64 (64 bit gcc 4.6.3) Desktop Gnome  (Gtk 3.4.2) dm mdm
>             Distro Linux Mint 13 Maya
>  Audio:     Card-1 Advanced Micro Devices [AMD/ATI] SBx00 Azalia (Intel HDA)
>             driver snd_hda_intel bus-ID 00:14.2 chip-ID 1002:4383
>             Card-2 Advanced Micro Devices [AMD/ATI] Wrestler HDMI Audio
>             driver snd_hda_intel bus-ID 00:01.1 chip-ID 1002:1314
>             Card-3 Logitech driver USB Audio usb-ID 001-005 chip-ID 046d:0826
>             Card-4 Logitech driver USB Audio usb-ID 001-006 chip-ID 046d:0a45
>             Sound Advanced Linux Sound Architecture v 1.0.24
> 
> Newer Linux is:
> System:    Kernel 3.13.0-24-generic x86_64 (64 bit gcc 4.8.2)
>             Desktop Cinnamon 2.4.1 (Gtk 3.10.8~8+qiana) dm mdm Distro Linux Mint 17 Qiana
>  Audio:     Card-1 Advanced Micro Devices [AMD/ATI] Wrestler HDMI Audio
>             driver snd_hda_intel bus-ID 00:01.1 chip-ID 1002:1314
>             Card-2 Advanced Micro Devices [AMD/ATI] SBx00 Azalia (Intel HDA)
>             driver snd_hda_intel bus-ID 00:14.2 chip-ID 1002:4383
>             Card-3 Logitech driver USB Audio usb-ID 001-005 chip-ID 046d:0826
>             Card-4 Logitech driver USB Audio usb-ID 001-006 chip-ID 046d:0a45
>             Sound Advanced Linux Sound Architecture v k3.13.0-24-generic
> 
> 
> On the newer system, I've lowered all sliders using the alsamixer, but no
> improvement.
> 
> Any suggestions are much appreciated.
> 
> Thank you.


My first bet would be that there was some sort of difference in your
setup, and that this was caused by hardware only.
But, there is also a chance something changed in ALSA.

I cannot give any other advice than to google on a combination of your
hardware, linux, alsa and perhaps words like noise, bug, etc.

/Kaj