But for me, sound quality isn’t about how loud you can crank the volume, it’s about being able to pick out the subtleties of the music. As Jon pointed out when he reviewed the Onkyo iPod Dock, connecting very high-end equipment to a device like the iPod will just highlight the limitations of the source device. With this in mind a solution like the iRhythms is probably preferable, although I found that even this speaker set showed that the iPod is far from the best digital music player from a quality point of view.
Let me qualify the above statement though, because I don’t want anyone attacking me for saying that the sound quality from an iPod is terrible, because it’s not. But devices from Sony and iRiver do manage to produce a more detailed sound envelope than an iPod when using MP3 source material encoded at the same bit-rate. Listening to an MP3 of Glory Box by Portishead (encoded at 192kbit) via my 4th gen iPod at a subdued volume resulted in a slightly muffled sound, with the upper end noticeably compressed. But firing up Fear by Ian Brown, also encoded at 192kbit showed just how amazing this combination of iPod and speakers could sound – the amount of subtle detail that could be picked out was superb, while the overall impact of this undoubtedly powerful track was maintained.
For comparison I connected a Sony NW-HD5 to the auxiliary input of the iRhythms and there was a tangible improvement in sound quality when playing back MP3 content. Switching to music encoded in Sony’s proprietary ATRAC format just took things to a completely different level. Of course if you’re an iPod user that’s concerned with sound quality you’re better of ripping your CDs to AAC rather than MP3 in the first place. There was a definite improvement when playing back 192kbit encoded AAC tracks on the iRhythms, while using Apple lossless encoding really showed what these speakers are capable of – although a 256kbit ATRAC encode on the Sony device sounded every bit as good.