Strange running/motor noise, please help diagnose

[Digitalwave]

Recently I noticed a mysterious sound coming from what sounds to be the engine bay. The sound is somewhat metallic, almost a grinding/rubbing noise. It sounds kind of like what a failed bearing sounds like.

Symptoms:

-the sound comes and goes. It's usually there in the first couple miles of driving the car, but then it will seemingly disappear (but not always).
-the sound is RPM dependent but does not have anything to do with the gear the car is in, it does it in neutral and rolling/full stop as well.
-it's loudest from 1k-2k and goes away by 3k. It's louder when the revs are falling back down especially from 1.5k-1k.
-the sound does not change when turning, braking, or doing anything else while driving.

I have searched through the engine bay a couple times, more extensively tonight. I have not found anything and really have no clues what to be looking for. This is what I have looked at/messed with so far, all to no avail:

-removed a/c belt: I thought it could be the compressor finally kicked the bucket. No effect.
-checked intake tract
-disconnected the air pump
-checked motor oil and ATF levels (thought it could be the steering pump, haven't ruled that out as a possibility though the noise does not change when turning)
-looking for any obvious vacuum leaks
-tested the fan clutch

I am having a very hard time pin pointing where the sound is coming from. My best guess is it's coming from the front of the motor, but when I have someone rev the motor for me so I can be closer to the engine bay it just stumps me further. I would say in front but underneath the motor. It may be something along the serpentine belt, but the belt and all tensioners/pulleys are only about a year old (8k miles). Perhaps it's one of the ancillaries? I'm lost at this point and any ideas would be greatly appreciated.

[m50commander]

did u check your pullies?

[ricerocket86]

did u check your pullies?

+1 Take the belts off and check all the pulleys.

[ricerocket86]

Just cause its new doesnt mean it cant be faulty. Just take off the belts and spin all the pulleys by hand. If you feel or hear grinding then thats your prob. Anti freeze on a belt wont make it slip. It will just make it squeal if it got enough on there.

[EastBayBimmer]

Try taking both belts off and running the car, (not long, it will drain your battery).

[Hellrot318is]

I just replaced a tensioner pulley on my 4 banger motor because it had a squeal during startup that went away during higher RPMs. Although mine seemed to be louder on idle.

[1997328IS]

My alternator makes a noise, if I hold my hand on the back of it I can tell that its the noise that I am hearing. Check it out.

[Digitalwave]

The bearings in the water pump had failed and there was about 1/2" of play on the water pump shaft that the pulley and fan attach to. Crazy! Quick trip to the auto parts store, and $67 + 1 hour of work later the noise is gone.

Thanks guys!