freesey
Adding a port to a non ported design can drastically change a speakers characteristics. Both an acoustic suspension design (sealed enclosure) and a ported design have advantages and disadvantages. And greater efficiency is an advantage of the tuned port design (thus the greater bass output - for a given power input). I don't really know the brand of your old ugly speakers, (is that a Smirnoff crown on the dust cap?) but if they are of a reasonably good design and manufacture, then you could really mess up the sound with a port. If you just want to experiment and it doesnt matter if you mess them up.. well then......
I suggest you search the 'net a bit and read up on some basics of speaker design and get some understanding for the different types that are built. (i.e. acoustic suspension, ported, tuned port, passive radiator, etc.) - and understand the basic philosophy behind the design principals - THEN decide if you want to poke holes in the cabinets.
Good Luck.
Randyman
