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

[MusicFan]

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.

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