This is a follow-up to last week's "Before you buy a sound bar speaker, read this" post, but this time I'm setting my sights on expensive, $400-plus iPod and Bluetooth speaker "docks." They have built-in limitations common to all single-speaker systems. They might have two sets of speaker drivers housed in a single cabinet, but when the drivers are just a few inches apart, "stereo" sounds more or less like mono. In the quest to make these speakers as sleek and lightweight as possible, bass and dynamic range capabilities are limited, compared with a pair of stereo bookshelf-size speakers. In a $100 or even $200 single-speaker Bluetooth system, those failings are understandable, but once the price rises to the point at which you could buy a decent set of stereo, self-powered speakers, like the Audioengine A2 ($199 per pair) or the A5+ ($399 per pair), Bluetooth models lose their luster. Better sound for the same dollars makes more sense to me.
To test my theory I compared one of the very best-sounding "docks," the Bowers & Wilkins Zeppelin Air ($600) with the Audioengine A5+s. To make the contest as fair as possible, my iPod Classic was directly connected to both, so I wasn't comparing wireless to wired sound, just the two speakers' sound quality.
To my surprise, the Zeppelin's bass was bigger and stronger than the two A5+s', but the A5+s' bass clarity outshined that of the Zeppelin. Individual bass notes were easier to follow with the A5+s. Those speakers, spread 5 feet apart, projected a broad and deep stereo soundstage. The Zeppelin's sound, from 5 or more feet away, was essentially monophonic. The A5+s had more dynamic life and superior overall clarity; they sounded more like a bona-fide hi-fi than did the Zeppelin. The A5+ can rock harder than the Zeppelin and sound great as TV speakers. Again, they'll trump the Zeppelin when used as a home theater sound system. I used the Zeppelin because it was handy, but I wouldn't expect other highly rated single-speaker systems to do any better in a shoot-out like this.
Oh, but the Zeppelin Air is a wireless speaker, and a lot of folks don't want to be tied down to a speaker with a wire or a physical dock. If that's a priority, stream your tunes to the A5+s with a $99 AirPort Express.
I'm writing this post not because I think everyone should abandon Bluetooth and other types of wireless speakers; they have their place. But stereo speakers have tremendous performance advantages over the wireless competition. If you care about the sound of your music, consider the stereo alternatives before you invest in a wireless system.