One thing to consider is that the speaker designer chose the internal volume of the enclosure based on the fact that it is ported. He would have probably used a smaller enclosure if he was using the same woofer in a sealed application. With the port plugged, there will be unintended consequences---you will have changed the performance and behavior of the woofer.
Does Plugging Bass Port Affect Pace, Rhythm and Timing?
Hi, I recently purchased a used pair of Monitor Audio Silver S1 bookshelf speakers for, well, my bookshelf. :\ As expected, the presentation is a little muddy, and the highs not as extended as they might be otherwise on these speakers known for the quality of their tweeters. I am about to try plugging the ports to see if any improvement could be had. I was wondering if there is any downside to plugging the ports on a bass reflex design as far as bass accuracy and speed.