[x1lexure]

It's about 3 mm wide, and on the right cup on the front where the "swinging arm" attaches to the cup itself. When it's on your had it cannot be seen as the "swinging arm" covers it up. What's this for? Air comes out of it when the pads are pressed together, but thwe left cup doesn't have one? I have been noticing that the pressure seems alittle worse in the left cup but the left cup sounds slightly more "full"? It's quite weird. Like the left cup is truelly closed and the right is sem-open. If I can get some pictures I will but...not right now.

 

[joelongwood]

Mine has a hole on both ear cups.

 

[lini]

Did you take a look at the front of the other earcup? On mine, the holes are present on both earcups, even on the same side - but you have to look at it from the side and turn it around!

Greetings from Munich!

Manfred / lini

 

[greenhorn]

Both earcups have each a hole, but you have to turn the headphones 180° to see the other hole

 

[JMT]

So do mine....it looked like an adjustment hole, until I tried to adjust the earcups. They wouldn't budge out of the original hole.

 

[Snufkin]

Like little ported subwoofers on your head

 

[Jackangel]

Although it's difficult to see, the bottom of each hole (on mine, at least) has a screen covering it. Gives me the impression that it's meant to let sound out in a certain way as to change/tame the sonic qualities of the headphones.