Improving bass from a front ported speaker

Agree...plugging the port often results in a muffled presentation...have u tried a sub?

You want to improve bass, not increase output correct? Try it, you cannot hurt the speakers.

Did you setup the speakers properly in your room? I had the same problem with my new ushers, they had too much bass when I placed them in the same position as my older ushers that were back ported. I divided my room in 1/5's for my speakers and chair, used the cardas alignment for side wall distances and things popped into place. I also put more sub traps in my room on top of what I already had. Now the bass is perfect.
Some of The reviewers of these speakers plugged the ports but I really didn't want to do that.

The bass output has more to do with room and less with the speaker. Where they are, where you are, where the boundaries are all the important questions. I would start from scratch with speaker locations before anything else. My favorite is the Sumiko Master Set plan. Formulas did not work. Every room has its quirks. Trust your ears.

Speaking very generally, stuffing a port will raise the speaker's low-end rolloff frequency, but at the same time make it more gradual. There are also many gradations between completely open and completely plugged, depending on the density of material you stick in the port.

I'm with Brf . . . give it a try, you won't hurt anything. The side-effect of sounding "congested" is also highly dependent on the particular speaker and how loud you're playing them.

As far as materials go, maybe start with your sock drawer? Worked wonders for those ubiquitous Cerwin-Vegas I remember from my college days.