Late 2013 15" Macbook Pro distorts audio with Facebook notifications?

So overall the audio has seemed pretty decent on the late 2013 15" Macbook Pro.

However, there have been a few occasions where I wonder if it's normal or if my machine may be defective.

A really easy example that other users could test for is on Facebook. The notification sound distorts and sounds like it's clipping/popping or otherwise struggling to play smoothly and sound good even when I'm around 20-40% volume levels.

It seems strange to me that this would occur on such a popular site on facebook, especially with my low volume settings. Can anyone verify if this does or does not happen on their 15" Late 2013 Macbook Pro?

I also seemed to hear a bit of "rattling" or vibrating sounds when watching a Netflix movie at max volume which caused me to lower the volume a few bars. I'm not sure if these are the type of speakers you are supposed to "break in" a little bit before maxing the volume? If so I would hope Apple would do that before shipment?

Well anyways I'm a little paranoid that something could be wrong with my macbook pro, it's hard to tell since it's not like every sound is obviously wrong. But the facebook notification thing is a bit much for me to ignore this issue...