Crackling Audio Peaks when using Headphone Output

Question

Intro and system

I'm experiencing problems with the headphone sound output of my HP Envy notebook (pretty recent model: 13-ab010nd, came out October 2016). I'm running Ubuntu 17.04 but the problem was also there in 16.10, and possibly in 16.04 as well.

It sucks, because I really need normal fidelity audio for sound-VR experiences. I am not a super technical Linux user, so I really hope someone here could walk me through or assist me in solving this problem. :)

Problem description

When I plug in headphones or speakers I very often, though not very consistenly hear the sound crackle seemingly on the volume peaks. Note: it is no continuous crackle when quiet or silent soundfiles are played, it happens just on volume peaks it seems. I have identified that it happens pretty much always when using Pure Data and it happens very often when watching YouTube videos. When these episodes happen the crackle is also there when playing music in Rhythmbox.

I've tried:

• Switching headphones; but it persists, also when I plug in speakers instead of headphones.
• Connecting a tv through HDMI does not seem to give audio trouble.
• I tried disabling Automute in Alsamixer; did up sound volume dramatically at next startup suddenly, but then went back to normal and the crackling persists.

Others with same issue

I googled around and these two forummembers seem to be encountering the same problem: Dan (April 4 2017) and nedned (December 26 2016). They have tried even more than I have, but still without success. One could think the issue is experienced only on more recent generation notebooks.

I really hope that somebody is able to help fix this issue, because it renders external sound sources pretty much useless. Please do tell me what you would like me to do or get and I will gladly provide it to aid in solving this problem, also for others in the future with newer notebook models.

EDIT: I have taken some more note of the problem: the crackle happens mostly in the left (headphone)speaker. Also, when playing a .wav file in the Videos application the crackling only seems to happen if the system volume is above about 1/5 of total volume. That's it for now. I really hope someone can help :)