Well, there is no sound coming from my realtek onboard HD audio. I tried to re-install, roll-back, and update drivers. I checked if the sound is all the way up, if there were errors in the device manager, and a million other possible fixes. And, the audio that DOES work (my speakers) is really acting strange. Why? Because when I play, for example, a youtube music video, one singer sounds as if he is 20ft away from the mic, another one sounds like they used 20 amplifiers whilst standing 1cm from the mic, and the instruments...sometimes sound weird. Hell, it's almost creepy, but thats not the point. The audio seems fine with speakers, but I primarily use headphones, and they worked fine two days ago, before I used my speakers to play a game.
P.S: I acknowledge this isn't related to a CARD, but I'm not sure where else to put this.
Are you using head phones straight from the motherboard audio jack or speaker set external control? Might be using the wrong jack on the motherboard.
Also Youtube sound quality can vary depending on the recording method. Not a reliable site to diagnose a problem.
Other things you could try are setting the operating system to stereo or lower the sound quality.
Edit: if you are using a speaker set which your headphones are connected to, make sure they’re connected right to the motherboard. Youtube is mostly recorded in stereo which may confuse your headphones rather if you have 5.1 speakers and hearing sounds (even though all messed up) could still sound ok.