XPS 17 9710 - Tapping Noise coming from left fan/speaker?

Hey Filbert, so after getting my torx set. i opened the computer to find minimal to low dust on the computer and no obstructions to the fans. after some research, i saw that i needed to get some thermal paste becuase i believed it was a heat sink issue. once i got it today, i opened up the heat sink to find the horrible paste job dell did but also that the heat sink had very little dust. after some cleaning, i would think that the tapping noise goes away but no. the tapping is still there and now i believe it has something to do with the top left sound bar. when you run the computers fans, there isn’t anything making the tapping noise from the fans or heat sink but rather, under the two usb c ports. i have to read the manual to get a better understanding but i’m not sure how i could fix an issue if it’s related to the sound board. is the bass thingy just bouncing a lot when fans are running? has it broken? im not sure what i could do since it’s seems like i’m the only one with this issue and i have never worked with sound parts. please let me know your thoughts 

The sound's frequency increases as the fan speed increases. It's possible that the fan bearing has worn. That could cause an imbalance and vibration. The vibration might be transferred to other laptop parts, so that while the most audible sound comes from a vibrating part, it could an imbalanced fan or worn bearing that is the source of the vibration.

As a comparison, when an acoustic guitar is strummed or plucked, a sound is heard. The sound comes primarily from the vibration of the soundboard. However, it is the vibrating string(s) that are the source of that vibration, transmitted via the bridge to the soundboard.

With proper ESD precautions (as I noted in a previous post), feel around to see if any part or board seems a bit loose or capable of vibrating when stimulated. If you can't find anything, I would be inclined to replace a fan (unless it's coil whine - see below).

Mysterious sounds, such as vibrations, are one of the bugbears of automobile repair shops. It can take hours to find the cause, often involving tightening and replacing various parts in a process of elimination.

Since this increases as the laptop's load increases, it's also possible that this is coil whine, which can sound like a whine, buzz, hum, scratching, rattle or vibration. It's hard for me to know, because I am not there to hear it in person. I have only your video to go by. You must judge. Coil whine can sometimes be quite loud with increasing volume as system load increases. See my post on coil whine.

I still lean to a fan being the issue, since you say that the problem began recently. Coil whine would generally appear even with a new system, though there's some evidence that imperfect soldering can cause coil whine. If it's soldering, that might occur later as an imperfect solder section loosens slightly, given the movement that a portable laptop incurs vs. a more stationary desktop system.

i have taken apart the motherboard from the computer and i see no imbalances or loose parts. i did notice that the noise would stop occurring whenever i would flip the computer upside down but right side up, the tapping noise would occur again. im not sure if it’s a fan because i don’t see any form of wear on it, additionally, whenever i use a blow dryer on the fan, the tapping noise goes away. im gonna try to open the fan to see if the bearing looks worn. do you have discord or a form of conversation i can message you personally?

So after opening the computer and inspected every piece of tech inside this computer, I believe it is the bearing. Now I just gotta spend about 35 dollars to get a replacement fan since Dell made it nearly impossible to open the fan to lubricate the bearing