Originally Posted by Zala

Assuming the sound recorder on your phone isn't playing tricks, that sounds like a higher pitched belt slip sound along with the normal low pitch the exhaust emits upon warm up. Am I right? If so, I've never heard such a sound on start up on my 2016 Nismo (if it makes a difference). Granted mine wasn't brand new when I acquired it either (had 10k miles) in case it's a non-broken-in engine quirk.

Lastly, do you hear that noise when inside the car with the windows up? That's been my driving lately (colder weather this week) and I haven't heard it.