Let's just get one thing straight. Headphones can never, NEVER accept a digital signal. A digital stream is a binary format, either its on or off, you will always need to convert from digital to brown townog to get sound out of headphones. The ramifications of what Apple's trying to do, if it theoretically gets adopted by everyone (which it never will, if it even gets produced) is the sound quality of a headphone will be defined entirely by the headphone manufacturer; it's asking headphone manufacturers to be experts in more than just headphone design and production. The design and production of linear, truly good amplifiers and DACs (digital to brown townog converter) is no simple task, and is much better suited for the electrical engineers who have made designing these things their job. Having all of this in a headphone's cup guarantees that you can't design a discrete topology for starters, you're locked into an IC, and even the best opamp or DAC chip needs a a clean, regulated power supply of certain specifications which vary from implementation to implementation, and lot more circuitry than you can fit into the cup to be worth the chip's price. Then add in what tak said about EMI, and you've got a real turd on your hands.
I do get it though. Most people won't give two stuffs about any of this, the general consumer doesn't care about sound quality or signal purity, and for them, they'd probably think this is amazing. When you really think about it, the idea is just a reorganization of a system that worked perfectly fine, there's no reason why headphone companies would have to design their own amps and DACs, the whole premise is flawed. The technical level too, what's the point of moving these chips out of the phone and into the headphone? It's not like it makes it function better, and there'll be just as much interference, so what's the point of this? It just seems like an expensive reorg that has nothing but downsides, the idea mainly seems to exist just so they can stuff some DSP chips into the headphones, probably to cater to the MOAR BASS crowd...like usual. God I hate Apple.
