Dell Vostro 3750 temperatures after subwoofer removed.

After 10 years of pretty active exploitation, subwoofer started to crack very loud. I removed the back panel where RAM is, and found out that the subwoofer membrane started to degrade, literally it crumbles like cookie.

So I managed to open the laptop and disconnect the subwoofer wire from the motherboard. And after I assembled it back i found out that my medium temperature decreased by 10-20 Celsius. Before that, when I was browsing youtube in 720-1080, my temperature were 75-85 Celsius, now they are around 65. I also wondered that my cooler system has almost no dust, i literally cleaned it with the alcohol napkin and it hardly became grey from the dirt.

And I remembered that I noticed back in the days, that my subwoofer was making weird clicking system sound when laptop was loaded with browser, applications and video games.

So my question is, could it be that my subwoofer was defective from the start, or does the subwoofer overall is the reason of high temperatures for laptops in general or this model in particular?