If I block the speaker, will it damage the drivers?

I have a pair of Paradigm 85F, pair of Totem Mini Sub and they are powered by Moon 340i Intrgrated Amp.

I found the mid bass is kind of overpowering and sounds blurry (this could be my room acoustic). But then I blocked the ports and immediately the mid sounds much better and I get clear high. The bass is still very nice from the pair of Totem.

Now, is this going to damage the drivers for long run? I just done it for like 5 songs and it sounds the way I like.

thanks.