Being a SAMHO newbie, I'm experimenting. I plugged the ports. Plugging the ports on the SAMs just made things too thin. But plugging the HOs is magic! I had to do some reading about what happens. Of course there is some differences of opinion, particularly about frequency response. The most common opinion is that plugging just causes the roll off to happen sooner. So bass is somewhat less loud. However the bass that remains is tighter. This is great for me given powered mid-woofers and subs as it makes integration work much better. I think it would work for anyone with just subs as well. Probably best with two.
More on point is that it increases coherence. Reading indicated a simple explanation. The port emits sound, as does the driver, of course. But that is two sound sources which causes phase issues. Plugging eliminates that.
To me, they now sound like SAMs with better dynamics and bass response.
Or maybe I like it as I cut my teeth on the New England sound: AR, Advent, KLH, etc. All sealed (acoustic suspension). I suppose the ideal would be to calculate the box volume for sealed; it is probably a bit different in required volume than ported. But it is working beautifully for me.
Anyone else tried this, or care to try and report results?
Are you ready for some football?! (I ordered black sponge balls)........Pete