Today I tried Ubuntu on my laptop Asus n550jx 64 bit version. Everything works fine except there is constant static/ hissing in headphones (in laptop speaker too, but its too silent to be heard). It uses intel 4th generation sound drivers or something liek that, on windows realtek hd drivers. Also hissing is constant - it doesn't stop if there is no music playing or something like, pop only happens when Ubuntu boots. Hissing doesn't become louder if there max volume, it happens even if there is speaker on mute( sound of hissing changes thought).
What have tried:
Mute built in microphone- no effect
Check playback settings with alsamixer. There was something loopback which turned off made hissing quieter, but its still annoying
Checked sound card power saving which was turned off
I know I am late to the party but I solved this on Ubuntu 17.04 by doing the following:
Open terminal and type the following:
and then press F6 and select your sound card. Use your arrow keys to decrease the volume where the hissing sound disappears (I solved it by decreasing it to green area only. See the screenshot). After that, adjust volume using standard volume control on Ubuntu (from Unity menu). You may have to do this every time you plug/unplug sound card but it has given me peace of mind really.