I also should mention one minor glitch I encountered on a very infrequent basis: namely, occasional low level “pops” heard when switching from one music track to another when streaming digital audio content from my PC to the Gem. The “pops” didn’t seem to be related to specific song tracks, album files, or USB cables, but in any event the problem occurs rarely and does not appear to do any harm.
Common wisdom might suggest that a Bluetooth interface, no matter how good, would inevitably fall short of the performance of a hard-wired connection to a DAC (the presumption being that something is apt to get lost in translation through the wireless interfaces). But in fact the Gem’s Bluetooth decoder comes close in many respects to matching to the sound of wired connections to its onboard DAC. Fundamental voicing remains largely unchanged, so that the primary difference I noticed with the Bluetooth decoder in play was a slight rollback in the acuity of upper midrange and treble details, plus a minor softening of transient attacks at the leading edges of notes. When you compare same musical tracks captured at identical resolution levels through the USB DAC and then through the Bluetooth decoder, the latter sounds slightly more softly focused and “polite,” but otherwise quite similar. For this reason, I would say the Gem offers the best Bluetooth implementation I’ve yet heard—one whose captivating three-dimensionality and smooth presentation are easy to listen to for long periods of time.
In my experience, pairing between my test Bluetooth player (a 3G iPhone) and the Gem was incredibly simple and reliable, though I have heard reports of some users needing to do bit of tinkering and troubleshooting to establish pairing between their Bluetooth devices and the Gem. One other point to bear in mind, based both on my own experience and comments from forum participants on the AVguide.com Web site, is that the sound quality of the Gem’s Bluetooth decoder is dependent to a degree on the Bluetooth software/firmware used in your player. For example, Apple sent along one of its periodic firmware updates for my iPhone as I was working on this review and after installing the update I noticed an immediate, albeit subtle, improvement in sound quality when playing the iPhone through the Gem. This leads me to think that the sound from the Gem’s Bluetooth decoder may get even better as Bluetooth firmware for playback devices improves over time.
To appreciate the remarkable naturalness and three-dimensionality the Gem provides, I played some 16-bit/44.1kHz tracks from Steve Strauss’ Just Like Love [Stockfisch, SACD]—an album thathas become something of a bellwether disk (on in this case, set of digital audio files) for me. Produced by the masterful Günther Pauler of Pauler Acoustics, this recording is rich in revealing instrumental and vocal details and is capable, when really high-quality source components are in play, of producing exceptionally wide, deep soundstages that seem to envelope the listener. As I played the track “Old Crow” through the Gem, several qualities stood out at once.
First, Strauss’ evocative baritone voice, which displays earthy textures with a just touch of grit at times, sounded spot on—full of nuance and warmth, yet never overtly rough-edged or harsh (which is how some competing USB DACs tend to render the sound of Strauss’ voice). Next, the sound of the late Chris Jones’ guitar was simply gorgeous, with appropriate body and warmth accented with smooth, sparkling high frequency details and filigrees that seemed almost to hover, floating in mid-air for a split second before decaying into silence. In contrast, some DACs give Jones’ guitar an almost hyper-detailed sound with jarring, jangly overtones that sound edgy and overblown. Finally, I was struck by both the roundness and tautness of the sound of Hans-Jörg Maucksch’s fretless bass—an instrument whose sound isn’t easy to get right. What the Gem did, in particular, was to reveal the deep bass body of individual fretless bass notes, while also showing how the instrument’s higher overtones have a tautly suspended and gently modulated quality (what I like to call the fretless bass’s characteristic “mwaaaah” sound) that reminded me, in some respects, of the sound of a tenor voice singing with vibrato. As I mentioned earlier, the Gem really does take a natural, organic, and holistic approach to music reproduction, giving listeners a sense for the whole rather than “deconstructing” sounds as some components do.