Knock acceptable while "cruising", how much?

I tried to capture the exhaust noise on video. The quality of the audio isn't the best and the actual footage can be completely ignored as I was rolling around under the car holding my phone near the exhaust. Does this seem excessive for exhaust rattles? I'm banging on the pipes between the header and the catback joint. No part of the exhaust is touching or even close to the body of the car, trans crosdmember, etc. it just seems that the exhaust itself is a little rattly. Thoughts?