Headphone volume low This just started happening recently. When I plug my headphones in, I get full high fidelity volume for a fraction of a second and then it becomes significantly muted.

I've checked "Sound" in Preferences to ensure that I've not reduced my system volume. 

Any other ideas on what might be causing this?

UPDATE:


Tried restarting (multiple times)
Tried resetting NVRAM to no avail


System Specs: MBP 15" Mid-2014 on Yosemite
I waited a couple of days and randomly I tried playing a video and the sound worked perfectly fine. I would just try waiting a couple of days like I did.