Sub Gen 3 emits weird noise

I have just recently added a Sonos entertainment system to my bedroom. I have the Sonos arc paired with a Gen 3 sub. The sub has been causing me many problems in my 2 weeks of owning it. The sub will sound amazing when first paired and it will be booming. However, over time the sound quality seemed to decrease and the oomph that the subwoofer had was completely gone. I would have to increase the sub level even higher than normal to even try to achieve the oomph I once had. I decided to purchase the Sonos Boost to help with any connectivity issues. I cant tell if the Boost really helped or not to be honest. If i place my ear close to the oval opening in the Gen 3 sub it seems to emit a sound that sounds like an old film reel ticking over and over. When the sub was performing at its best with the oomph I was looking for, there was no weird film reel ticking sound when i put my ear close to it. I just want to figure out what the hell is wrong with it. Im sick of purchasing more things to try and fix a problem that shouldn't even be there in the first place…