I have a pair of Tannoy Mercury MX3 front speakers and a pair of MX2 rears. The MX3 floorstanders have a forward facing bass tuning port and the MX2s a rearward facing one. They came with foam bungs in them which I assume were just for protection in packaging so I took them out. Now I've read that perhaps that isn't what should be done. So, what's the difference between having them bunged up or not? I still have the foam bungs. Michael.
It depends on the position of your speakers and your room acoustics. If you have enough free space towards rear and sidewalls and if you have a tight, smooth bass without the foam plugs, I would of course let them out. In case the bass is boomy and not too precise without the plugs, you should put them in, especially if your speakers are placed near walls. With the foam plugs put in, you have a closed speaker, the bass is often more precise, but less deep. Just have a try with both options, and then decide.
I prefer my speakers with my bass ports bunged. I found that the lower midrange improved and the whole sound flowed more. But its really about taste, as well as placement