Poor ear speaker sound quality

I replaced a cracked display on my wife’s iPhone 6s with one I purchased from iFixit.com. Everything went smooth and everything is working but the sound from the earpiece speaker sounds muffled. Every time the person on the other line speaks, there is a buzzing distortion that makes it hard to understand at times. It’s similar to how it might sound if a regular speaker cone had a tear in it.

I took it apart again and ensured that all my connections were good and it did not make any difference.

Could it be a defective earpiece speaker in the replacement display unit?