If you've seen some of the recent threads on this issue, you'd notice that some people who have heard both swear that they sound virtually the same, and others claim that the Senns have the edge. I only have one of the earphones in question, but speaking as someone who knows a bit about product design and branding practices, I would be very surprised to find that there really is any difference. Why would Sennheiser spend money engineering a superior IEM, and then use the same housing as a cheaper model marketed to a different audience by a different company? It's absurd.
It's far more likely that a company or consortium planning to sell an item at different price points would cosmetically change the housing and leave the guts alone than that they would reengineer the electronics and stick with a housing visually recognizable as belonging to a cheaper brand. And until one of the three companies selling these headphones comes clean, we won't know for sure which of them commissioned the design and which licensed it. I'd guess that only Sennheiser has a serious in-house headphone design team, but I'm sure that there are now product design firms that handle headphones for several companies. And sometimes even high-end companies like Sennheiser will rebadge someone else's model to fill a gap in their product line-- does anyone remember when high-midscale Honda sold downscale Isuzu Rodeos as Honda Passports for thousands of dollars more money? Have you heard of the Saab 9-2x, aka the Saabaru? We could make the same comparison with toasters, or wristwatches, or anything else you cared to name.
So what I'm saying is that you might as well trade in for the creatives. There may, however, be a real difference in the sound between any two pairs, but I'd bet that this would be more attributable to different batches from the factory in China than to real design differences apart from the J to Y cord. I'm guessing a large batch was messed up, or there wouldn't be shortages of ep-630's at distributors at the same time as a huge number of OEM ep-630's with CX300-style J-cords showed up on ebay. Duh.
But maybe Sennheiser did detune the CX300 when Creative and Sharp asked to sell a rebadged version. Hey, that's what Etymotic claimed they did for Altec Lansing, right? But if we really believed that, then why are we all racing to buy im-716's?
