I'm using Sennheiser HD280s with an HP ENVY 17. I've run into something similar with my laptop. You're not the only person to encounter this.
I mean, the motherboard makes a huge deal out of their onboard sound hardware, but I can barely use it as is. I find it hard to believe that I'm the only person that's ever encountered this, but I might be wrong I've got media buttons & whatnot, it's just that 2/100 (for both overall volume and individual sources.I really feel like that should be a percentage, but that's irrelevant) is already 'normal' volume, so there's nowhere to go down.
Well, I don't mind either permanently putting a volume control cable on the back of the machine, I just wanted to see if there was some software issue.