[SOLVED] Sound from browser coming scratchy

[Fuffy]

EDIT: Solved by just opening the settings in my debian, the audio output (line-out built-in audio) was set to 130% and setting it back to 100% solved the issue.

Hello, this started out of nowhere (I didn't changed any software or hardware, only default OS updates). All audio output, whether playing videos on youtube or songs from whatever online audio stream or even when playing downloaded music through the browser (offline) gets the sound to be scratchy. Volume is fine. No other distortion is perceivable. Playing the same audio or any movie through other applications (VLC, native Movie etc) generates a clean sound.

On this same PC I also have a Windows 7 Ultimate installed, whose all sounds generated from browser (including Firefox Quantum and Chrome) and other programs alike are clean. I can spill more info if it helps.

My system specs:
- Debian 9.3 stable (stretch)
- 4GB RAM
- 140gb available with 22gb still available/empty (shared HD with other OS)
- Pentium(R) Dual-Core CPU E5300 @ 2.60GHz
- Intel NM10/ICH7 Family High Definition Audio Controller
- VGA Cable connecting GPU to monitor (so no HDMI or adapters here)
- Sound box connected to standard audio jacks (in motherboard)

What I tried so far that did not helped:
- Restarted several times and also left the computer off for a day.
- Downloaded Chromium (from package manager) and Firefox Quantum (directly from website), both also produced scratched sounds.
- Checked and installed general updates.
- Checked cables and other physical stuff (well, other apps generate a clean sound, so I doubt it is a physical issue).
- Googling and binging around, all I find are "no sound" problem threads that I could not use their troubleshooting methods to fix my stuff.

This already lasts for more or less two weeks. Any insights?

[Wheelerof4te]

When did you upgrade? How? Were there any errors?
Stretch has problems with sound, at least it did have on my laptop. I think it's a bug or misconfiguration in Pulseaudio. Have you tried suggestions from the Wiki?
https://wiki.debian.org/PulseAudio#Solving_Problems

[Fuffy]

The general OS installation is a fresh Debian 9 stable install, so no OS upgrade from 8 to 9, but once or twice a week my "Software" puts up the notification to install updates, including system updates. Not every week of course, but this month it has updated stuff like 5 times. So that's the how, through automatic "Software" updates. No errors on the update process (that I was notified of). Yes, I did tried the wiki stuff, also no high CPU usage when playing, for example, music in youtube.

EDIT: I'm running on this install since Debian 9 was released.

[Wheelerof4te]

For me, sound stuttered when opening another application, for example browser while music was playing. I honestly think it's a bug. When exactly did you notice it? Was the problem there before, or it started only recently?

[Fuffy]

Solved by just opening the settings in my debian, the audio output (line-out built-in audio) was set to 130% and setting it back to 100% solved the issue. Jesus, never thought I'd fall for such simple problems. @Wheelerof4te thanks for sticking with me!