My bottom speaker volume got lower and produces "screeching" sounds

Hello, I'm just here to double check if this the bottom speaker is indeed the one faulty before ordering and doing the replacement. Ear speaker works fine but the bottom one produces a "screeching" sound like the ones with a low-quality speaker also the volume of it is lower than when I first bought it. I compared it with my brother's phone as we have the same phone.

Thank you!