Hole in intake

I took off my intake to clean my IAC with some rubbing alcohol and I found the attached hole that was rubbed by my alternator pulley.

Does anyone know what this box does and if the hole would affect anything, like idle?

http://en.wikipedia.org/wiki/Helmholtz_resonance

and yes a hole will effect your idle.

Wouldn't it also cause in issue with the air/fuel ratio as un-metered air is getting in the intake?
Could it also slightly change the temperature of the air, its now coming from behind the radiator rather than by the exhaust header?

Thanks Rogue and EricJ!

And unfiltered air i.e. dirt.

Aftermarket intakes often eliminate the box in their design. Not sure what loss/benefit this has.

I was able to pick one up from Rogue at Miata Solutions for a nice price. All installed and seems to have fixed my idle issue, or the rubbing alcohol did.