And, its audio system, while not a technical tour de force, is more than up to snuff – especially at normal listening levels. Case in point:
Volume matched ‘Normal’ listening levels for Ultrasone IQ:
Plenue D VOL42
AK Jr VOL40
Prior to engaging its amp, the iPhone 4s is nearly hiss free. After engaging it, it hisses just slightly more than the Cowon Plenue D. Both hiss much less than the original AK100, which debuted a year after the iPhone. As you can see from the graphs above, the iPhone 4s is no slouch, either. In fact, it squeaks by the Cowon Plenue D in THD and IMD scores and squeaks by the AK Jr in both noise level and dynamic range. It is trounced in stereo crosstalk by both competing machines. But then again, it is a 5 year old phone built for a mass audience. The volumes at which I tested it are roughly 6dB beyond my comfort zone. Had I matched the volume to my taste, the differences between devices would slim even more.
Also note, that at matched maximum volume settings, iOS9 measurably outperforms iOS8. That said, at max volume, it is handily beat in most metrics by both the Plenue D and AK Jr. But if you’re listening to it at maximum volumes through any earphone, metrics won’t matter; hearing aids do.
Modern iDevice’s greatest coup is gapless playback. Not only of lossless files, or whilst reading a matching cue sheet through a third-party app. Gapless playback works seamlessly when playing MP3 and AAC albums. Outside of MiniDisk, iDevices, and Rockbox are your only contemporary choice for full proof gapless playback.
If you want parametric EQs, you can get them from the App Store. If you want DSD and FLAC playback, App Store. If you want hundreds of simulated volume steps, App Store. Which is to say: at normal listening levels, a 150$ to 200$ 64GB iPhone 4s isn’t just a steal, it’s ready for audiophile prime time.
Speaking of, what attracted me first was its subjectively warmer musical draw vis-a-vis my iPhone 6. That and the colours. And the flush camera. And the nice buttons. And the corners. No, there’s no comparison. The iPhone 6 sounds good and performs well. But it is the ugliest phone I’ve handled in years. If the iPhone 4s is an old Leica, the iPhone 6 is a sad Canon JII. And like an old Leica, it’s more than just iconic; it’s addictive.