Monitor Audio 12i center has muffled sound

Newbie here. I recently purchased a used Monitor Audio 12i center speaker based on the recommendation of an "audiophile" friend. I am putting DVD and TV audio output through my amp. The sound through the 12i from a DVD is fantastic but the sound from TV output is fairly muffled and I have to keep turning up the volume to get decent sound. Previously, I used a Boston Acoustics Lynnfield VR10 and it sounded very good with the TV output.

When I was looking in the open front ports of the speaker I see thick foam lining the bottom and back of the speaker (it may also line the top and sides but I can't tell) and wonder if this has anything to do with muffling the TV sound. Does anyone know if this the way a 12i came from the factory...is this done, in general, to center speakers? Hard to figure why is sounds so good with DVD but not TV. Thanks in advancd for any info/advice.