Let's say you dropped $300-plus on a nice set of wired AKG, Beats, Beyerdynamic, Bose, Bowers & Wilkins, Grado, Oppo, Sennheiser or Ultimate Ears headphones. Then later, you bought an iPhone 7 and discovered it doesn't have a 3.5mm headphone jack onboard. Are you going to toss your headphones to get a set of Bluetooth headphones that don't sound as good as what you have now? That doesn't make any sense.
Apple nixed the 3.5mm headphone jack on the iPhone 7, and there's not much chance it'll return on iPhone 8, but what are folks with nice wired headphones to do? Sure, they could use the Lightning-to-3.5mm adapter which comes bundled with the 7, but that's far from an optimal solution. And that's not just my opinion, it's one of the poorest-rated products on Apple's own site with 209 one- and two-star reviews! Apple customers really don't like the adapter.
Now, with FiiO's nifty i1 headphone amplifier and digital converter, iPhone 7 (and presumably iPhone 8) users have a better option. It sells for $40 on Amazon in the US and £50 in the UK. (The Australian price hasn't been set, but you could expect it to sell for around AU$80.)
Naturally, we had to compare the two adapters, FiiO and Apple. Starting with a Sennheiser Momentum 2.0, the i1's bass definition firmed up compared with the Apple Adapter. With "Pink Up" from Spoon's "Hot Thoughts" album, the drums and vibes have a lot of reverb, and the i1 sounds clearer than the Apple adapter. Not by a huge amount, but the differences are there.
The changes were more obvious when I plugged in myon-ear headphones. The Apple adapter sounded muted and dull; the i1 had more life and energy.
I also tried the i1 with some in-ear headphones, starting with my Ultimate Ears UE900, and the sound quality differences were slight. So I'm not all that convinced that i1 is a big enough sonic upgrade over the Apple Adapter with every headphone. However, the good news is that significantly better sound is available from the($99, £89, AU$160) and DragonFly Red ($199, £169, AU$320) portable headphone amplifiers/digital converters that work with iPhones. The catch: they're the size of a USB flash drive, so they're bigger and bulkier to carry around than the i1.
The i1 cable has a mic and inline controls, but call sound quality was a little muffled. There were instances where the i1 didn't play music at first, but unplugging and replugging the Lightning connector once or twice usually brought the sound back to life. What can I say -- the Lightning plug isn't the most reliable connector for audio devices.
The FiiO i1's 32-inch (81mm) cable was too long, I'd be happier if it was half that length, but as it stands, the i1 is a viable alternative for iPhone owners who have a decent pair of wired headphones and want something a little better than Apple's less-than-stellar Lightning adapter. I'm hoping even better adapters will eventually show up, but for now, I'm sticking with my iPhone 6S that has a 3.5mm headphone jack and the Lightning connector.