Hi guys!

Quick question here - I recently bought a pair of AKG k702s, and they sound really great and detailed. However, it seems that at low frequencies the left driver seems to rattle noticeably. I'm kind of a newb, but is this a sign of defect or does this mean maybe that I need an amp?

Also I've been hearing some occasional crackling, which I can only assume is due to lack of amplification.

I would appreciate any help at all, thank you very much in advance!

Additional info:
- Currently plugged in straight from my laptop.
- Rattles at about 85 Hz using a headphone bass test track off Youtube.
- First noticed rattling while listening to 'Dreaming of the Crash' (Hans Zimmer, Interstellar)

There might be a hair or some other object on the surface of the driver. Remove the pads and blow gently onto the speaker and see if it helps. You can also use flashlight and check out if you can see what is wrong.
 
It is possible that your headphones are defect. Loose voice coil can be a source of the rattle. You might be able to see the coil of of copperwire coming out of the magnet when the headphones rattle.

Thanks for your reply, Roderick. I've opened up the pads but I can't find anything on the drivers, and the rattling sound persists even after blowing on it. Oh well I guess I'll find tech support or something. Thanks very much anyway