Headphones making bubbling sound if microphone not plugged in.

As the title says, my headphones are making a strange, bubbling / gurgling noise instead of playing sound. I managed somewhat of a fix by adjusting the balance in the levels tab of the speaker properties, like so:
Which allows sound to be played but it's quite quiet unless I pump the volume way up.
Now, I borrowed the room mates headphones which has two plugs, one for the headphones and another for the microphone (I thought of this because I let them use the laptop earlier whilst theirs was getting fixed and they had these headphones plugged in, with the mic) to test it. With both headphones and mic plugged in, normal sound without issue.
However, if I unplug the microphone from the jack? Exactly the same issue. If the balance levels are even, I get the strange gurgling noise instead of sound, be it a video or music. I've tried uninstalling drivers, disabling the laptops mic but nothing.
So, anyone got any idea's what the issue is? Everything was working fine as of this afternoon until the headphones and mic were plugged in, now this.

Oh, and the laptop speakers work perfectly fine, no issues there. Just the headphones when plugged in without a mic.
And to clarify, my headphones are simply headphones, no mic.

Small update: Sound plays perfectly when I run the "Test" option.