Improving bass from a front ported speaker

Move the speakers closer to the wall behind them. That should help. Plugging the port is not a good idea, IMO.

Agree. Plugging the port will skew the balance and literally make your speakers sound "congested," especially for male vocals, tenor sax, cello, etc.

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.