You need to diagnose with car no moving first..like Dirt J mentioned above....
- Does this noise happen consistently at 2k RPM or does it only happen sometimes? If it happens all the time, it will be easy to track down . If it only happens sometimes it will be a bit harder...
- Does the noise go away when you climb in RPMS
- Is the engine quiet/running good at idle?
- any recent work done?
- Park car, pop open the hood, and rev engine to 2k or whatever it takes to try and re-create the noise
>> If you hear the noise, you can eliminate anything drivetrain related
>> if you don't hear the noise, then you have something going on with drivetrain / tires / etc. and it will be a bit tricker to narrow down. May need to get it on a lift.. or maybe get a little go pro camera mounted down there to look around while driving.