Strange metallic rattle at around 3-4k rpm.
 

You can hear the sound right at the very beginning of the video. It comes and goes throughout. This sound is very intermittent, but seems to be increasing in frequency. The video is less than worthless, only the audio is of any use. You might have to turn up the volume to hear it. It's a cell phone video, but it's the best I have of the noise.

Once it starts to happen, I can modulate the sound by modulating the throttle. More throttle makes for more noise, until about 4k when it goes away

Pressing the clutch slightly (maybe 1/4" - 1/2"?) makes the sound go away immediately.

I've had it happen in all gears.

Increased engine load seems to make it happen more often. For example, climbing a mountain pass will almost certainly elicit the noise.

I didn't notice it until I moved from OH to CO. A coincidence I think.

Without further adieu:
[ame="http://www.youtube.com/watch?v=XxfdT4Lha60"]YouTube[/ame]

video is private.

that said, do you have a visconti flash? if so, he said this noise is his "secret sauce"

Can't tell if you're serious, or if this is a joke. His "secret sauce"? Really? Creating unnecessary noises, without explaining what it is? Personally, I wouldn't be okay with Visconti's explanation.

Doh! Thanks.

And no, my car is completely stock.

Finally made some progress on this problem. Went for a ride with one of the guys from the dealership that I'm working with now (working with the previous one was like trying to push a rope).

We reproduced the problem, and now both of us think it's something with the clutch mechanism. The biggest reason we think it's the clutch is that pressing the clutch just a tiny bit can can change or even silence the sound. When I say a tiny bit, I mean a very small amount. Just enough to take up the slack in the mechanism, but not enough to slip.

It's going in next week to get outfitted with chassis ears, so they can identify where exactly it's coming from. Then I'm betting they'll have to drop the engine and transmission to get a look at it.

Wish me luck.

Brett

Sounds like a throw out bearing.

I get this too but its soo random. Didn't have it for months but heard it last week.

Please report back

I get this noise when I'm slowing down in neutral sometimes... Happens in 2nd and 3rd gear that I have noticed so far

sounds like something is vibrating and hitting something.

My brz was making a metallic rattle at about 4k... Turned out to be the snap on the seat belt retension strap on the passenger seat. It was surprisingly loud! Sound on your video seems much louder.

And it's also definitely coming from the engine bay :)

Roger that. Will do. It will be going in next week, now that my new window switch has arrived too. The good dealership is far away, so I try to combine trips.

Status update Mr. Brett :)
ty ^.^