I bought a pair of earbuds on eBay and I'm slightly concerned that they could be a knockoff. Its pretty difficult for me to tell if they are fakes or not since I have nothing to compare the sound with, and as far as I know, it sounds fine and better than my previous earbuds.
Are there any simple methods to gauge the performance of the earbuds so I can get some numbers to compare with existing data for my earbuds? Things like impedance, frequency range, etc