How is the sound quality between the Nano 7G and the Shuffle 4G? For better or worse?
I know they use the same Cirrus DAC (from looking at the ifixit teardown pics on the logicboards).
The Nano 7G sounds a little "softer" around the edges compared to both the Shuffle 4G and the Touch 5G. When I say softer I mean there's a little less clarity. The difference is subtle - they all sound like iPods in general and this is not a deal breaker if your heart is set on Apple, at all. Darker, looser, low-detail headphones may even drown out this difference. But if we strongly insist on discerning a difference between the three, and using a variety of IEMs, then I think I can hear this. The Shuffle comes surprisingly close to the Touch in sound sometimes, particularly clarity.
A song I often use for auditioning is Gotye's "eyes wide open" - I often saw it on demo units, so I bought it off iTunes for a comparison with my own players. It's the kind of music that really benefits from the colder, more analytical iPod sound in general (as opposed to say, the warmer fluffier Sony sound). It is this song that single-handedly persuaded me of the benefits of the iPhone 5/Touch 5G's digital amp.
To me the song clearly "rocks" a little more on both the Touch 5G and Shuffle 4G over the Nano 7G. The synths and vocals just pop a bit more.
The Nano 6G also has a tiny bit less clarity compared to the Shuffle 4G and the Touch 4G. The Nnao 7G is clearer than the Nano 6G but still softer than the 2 products I mentioned above. The 6G can sometimes rides a line where you're not sure if its amp is sufficient or underpowered, neutral or plasticky-sounding; my ears subjectively think the 7G is better in this regard.
After sampling these iPods extensively (going to stores for 3 months on-and-off) I bought 2 Shuffles instead of a Nano 7G. If you're looking for a fun sound, I actually think nothing beats the Shuffle in its price range. It hasn't got EQ so it's not a bassy kind of fun, but that can be easily fixed by the endless array of IEMs and headphones today that (without declaring so) are really tuned to be driven much better by Apple products. Say, the entire Zound Industries lineup (Urbanears/Marshall/Coloud/etc) is designed to provide so much bass that you don't need to EQ for bass, just EQ for how much treble and mids you want.
I don't think the Shuffle actually has any Cirrus Logic parts - I cite the iFixit teardown frequently and I've never seen it on there - I just assumed everything on the Shuffle is contained in that custom SoC. Also worth noting is that multiple Sony Walkmans use Cirrus Logic parts but the sound is digitally tuned to give a very different sound.
There's also a theory that Apple intentionally tuned the Nanos to have a somewhat softer sound than the other iPods and iOS devices - which I agree with. But these are all just my opinion
