Everyone's Favorite Game: Name That Noise

[ryanheacox]

I'd like to call on everybody's collective expertise to help diagnose a new noise my A is making.

First, here is a link to a video of the noise, https://www.youtube.com/watch?v=SMkSiOYlupI

In the video, I'm coming down a hill. First few seconds, the clutch is in and I have the hand throttle set to about the correct engine speed for 30MPH. Rest of the video, the car is coasting in gear still around 30.

This noise doesn't seem to be coming from the engine but it does seem speed related(faster when the car is moving faster). Sitting still and revving the engine doesn't make the noise.

The only times I've heard have been coasting down hills and as the revs drop between shifting.

Also, seems to be coming from under the floorboard instead of under the hood but it's hard to tell.

Thanks guys.