MakerBot Industries

Yes, that's the sound it's supposed to make as it pulls a slight vacum sucking the filament up. You also get a "slap" if using a filament box with the tube since it follows the reversal and then slaps the body of the filament drive on the fast forward of the filament.

Like my drill instructors said, "the Pain is there to let you know you are still alive"!

So in our case-the sound lets you know reversal is working. Printing someting like the cathedral play set will invoke this to the max, but that's what makes the perfect prints around the window frames.