Streaming music is the next big thing in audio, according to many industry insiders, but the sound quality of streaming audio can vary from not even worthy as background music to so good that it drags you in from another room. Obviously, we audiophiles are more interested in the latter than the former. The new Cambridge Audio Minx Xi attempts to bridge the gap between the convenience and reliability of a Sonos system and the sound quality of something better, such as the late, lamented Logitech Squeezebox Transporter or the new Sony HAP-Z1ES. For $999, the Minx Xi includes a plethora of features and capabilities in a relatively small and user-friendly package.
The Minx Xi is, in essence, an audio receiver brought into the 21st century. Inputs include two analog, one digital Toslink, one digital S/PDIF, two USB 2.0, and a BT100 Bluetooth receiver. Outputs include a 3.5mm stereo headphone output, a line-level subwoofer output, and one pair of high-level speaker outputs. The Minx Xi's power amplifier section produces 40 watts RMS into eight ohms and 55 watts RMS into four ohms. The Minx Xi supports a plethora of digital formats, including ALAC, WAV, FLAC, AIFF, WMA, MP3, AAC, HE AAC, AAC+, and OGG. High-resolution fans will be somewhat disappointed to find that the maximum sample/bit rate supported by the Xi is 96/24, regardless of the digital format or input used. Also, the Minx Xi does not support DSD and DXD. The Minx Xi's digital section is based around a Wolfson WM8728 DAC chip, and the Minx Xi uses external clocking taken from the Cambridge Audio NP30 network player to reduce jitter from digital sources.
The Cambridge Audio Minx Xi has what I would call a "half-size" footprint that is 3.5 x 10.6 x 11.2 inches. My review sample had a white chassis, but the Xi is also available in black. Given the number of inputs and outputs on the Xi and its small size, it's a wonder that its rear panel is not a complete jumble. Except for the speaker terminals (more about them later), physically connecting the Xi to a system is easy. The Xi can be operated from its front panel, where you will find a full set of controls that use eight dedicated push buttons and one large rotary control. The rotary control can also be pushed in to enter a selection.
The Xi comes with a full-featured, wand-shaped remote control that includes all the functions accessible from the front panel. For some functions, such as adjusting the treble or bass levels, the remote navigates through the Xi's controls quicker than its front-panel buttons. Cambridge Audio also has a remote control application available for Android or iPhone called "Stream Magic". The addition of a WiFi app increases the Xi's placement options exponentially. You can put it in a closet or inside a cabinet and still be able to operate it via the app, since line of sight is not needed for its WiFi connection.
Setting up the Cambridge Audio Xi was simple and straightforward except for one detail: the speaker output connections. Cambridge Audio developed a variation on standard speaker terminals that uses a special dedicated spade-lug-to-banana adapter. The problem with the adapter is that it moves freely and can swivel easily - so easily that you can, if you aren't careful, hook up large spade-lug-equipped speaker cable in a way that causes the spade lugs to touch. If that happens, you've created a short that could damage the Xi's power amplifier. I used a piece of cardboard between the two speaker connectors to prevent this from happening, but I can't help but think that some users will find, much to their dismay, that their Xi only works on one channel because they have inadvertently shorted out one of their speaker outputs during installation.
Once you've hooked up speakers, you're ready to turn on and set up the Xi. The turn-on sequence takes a while; I timed it at 50 seconds. While energy-use-conscious owners may want to turn the Xi off from the front panel when not in use, the long turn-on time may push many owners into using the mute button instead of powering down the Xi when it's not in use.
The Xi lets you use either a UPnP-aware NAS drive or a USB-2.0-compatible hard drive as your music library source. You can also access your music from USB thumb drives by inserting one into the front-panel USB connection (which can also charge your iDevice.) In my system, the Xi did not find my Buffalo HS-500 Linkstation NAS drive. After quite a bit of research, I found out that this particular NAS was not natively UPnP-compatible. Because I was near deadline and didn't really want to go out and purchase a new NAS drive quite yet, I used a large USB drive with my music files for most of my critical listening sessions. Later, I hooked up an old LaCie HipServe NAS that I had retired from duty a couple of years back, and the Xi recognized it immediately.
Once the Xi was fully set up, I found day-to-day operation to be glitch-free. I was able to find and access my favorite radio stations via the Internet, save them to the Xi's memory, and play them easily with no dropouts or buffering errors. My own music files on my attached USB drive also played flawlessly through the Xi. After a couple of days' use, I found that I preferred to control the Xi via its app, as opposed to using the wand remote or front-panel controls, as the app allowed me to navigate through my music libraries more quickly. I also preferred the app when surfing though Internet radio stations; again, the app delivered quicker response and more information than the Xi's front panel with its scrolling lines of LEDs.
Besides access to virtually every Internet radio station on Earth, by country, the Xi also supports "streaming radio" from BBC iPlayer Radio, Pandora, Live365, Rhapsody, and Aupeo! I have a Pandora account that I use on occasion, which worked fine with the Xi after a rather long initial search. I also connected the Olasonic Nano-compo Nano-CD1 transport to the Minx Xi via Toslink and S/PDIF digital connections and found it to be a very synergistic combination. The Minx decoded both digital streams from the CD1 transport without any issues. Due to the Nano-CD1's small size, it fit quite nicely on a shelf next to the Xi. The two components even had matching white cases. I also connected and used my Logitech Squeezebox Duet with the Xi via its S/PDIF and Toslink digital outputs. Once again, the Xi decoded and played all the files and streams that the Duet sent it without any hesitation or glitches.
Click on over to Page 2 for the Performance, the Downside, the Competition and Comparison and the Conclusion . . .
I suspect that, in many homes, the Minx Xi will find itself in a small room or den system. It may even wind up on a shelf right next to a pair of small, modestly-priced speakers. Sonically, the Minx Xi is better than that. With a pair of properly set up, highly resolving small speakers, such as the Audience Clair Audient "The One" speakers, and a subwoofer, the Minx Xi can create dimensional, involving, and musical results.
During my listening sessions, I used the Minx Xi with several small high-performance monitors, including the ATC SCm7 rev3, Silverline Minuet Supreme, and Audience Clair Audient 1 + 1, plus an M&K MX700 subwoofer. I compared 96/24 and 44.1/16 files that were downsampled from my original DSD 128x masters. On a recent recording I did at the Salina Schoolhouse featuring the acoustic group Taarka, it was easy to hear the improvements wrought by the higher sampling and bit rates through any of the speakers I used. Not only was the imaging more definitive on the 96k files, but the low-level detail and acoustic qualities of the recording venue were also easier to hear. I especially like the way the 96k version captured the subtle textures and inflections in Enion Pelta-Tiller's unique vocals. The Xi's lack of noticeable additive or electronic colorations allowed well-recorded music to retain its own intrinsic textures and tone colors.
Next, I switched from a small ensemble to a full symphony orchestra, using my recording of the Boulder Philharmonic performing the Sibelius Violin Concerto OP 47. Once more, the sonic differences between 44.1 and 96k files were quite obvious. The 96k file was easier to listen into than the 44.1, with a greater sense of Macky Auditorium's acoustics. Dynamic peaks displayed less dynamic range than I've heard using components with more powerful (or standalone) amplifier sections. At times, the Minx sounded as if it had a limiter built in, which prevented speakers from getting to that fff level; instead, ff was the max. Also, compared with my other room-based or computer nearfield systems, the Minx Xi didn't have quite as much micro contrast to differentiate subtle differences in dynamics within the music. The differences were still there, but just not quite as prominent as in my other systems when playing the same tracks.
The shortcomings of the Minx Xi are minor but still worth noting. The first downside is the long turn-on time, which from the push of the "standby" button to full operation took, on average, 50 seconds.
The second potential downside is that, for access to a NAS drive, the drive must be UPnP-compatible. Most new NAS-capable drives will have UPnP capabilities, but some may present problems, such as my soon-to-be-retired Buffalo Linkstation (I bit the bullet and went for a two-bay Synology DS213J NAS enclosure and a Hitachi Enterprise level 4TB drive to replace it).
The third issue I had with the Xi was its speaker terminals. It's far too easy for the supplied banana-to-spade-lug adapters to rotate when using large spade lugs and cause a short between the hot and ground speaker connections, which could seriously damage the Xi's power amplifier section. And speaking of the power amplifier, it's only so powerful: if you try to drive inefficient speakers or need to fill a big room, the Xi's power amp may not have quite as much power as you really need.
The final issue with the Xi is that it does not support 176.4/24, 192/24, 64x DSD, 128x DSD, or DXD music files. This limited ultimate high-resolution capability could seriously truncate an end user's ability to enjoy some of the higher-definition files in their music library. And, as high-resolution files become more prevalent, this lack of complete high-resolution mastery could limit the Minx Xi's longevity in some systems.
Competition and Comparison
Wireless and wired music servers have proliferated in recent years. Sonos probably has the largest market share and is the most ubiquitous brand. Compared with the Sonos ZP-90 (now superseded by the Sonos Connect:Amp), the Xi has more high-resolution capabilities, more input options, doesn't require its own dedicated and closed WiFi network, and sounds quite a bit more detailed and musical. The Sonos does offer an easier setup and the ability to easily add extra rooms to the system, however.
I recently received the new Moon Mind 180 streamer ($1,295) from SimAudio. It has all the Internet radio, NAS drive, and similar streaming abilities as the Xi, but it lacks front-panel controls, a direct USB drive connection, and a dedicated remote. The Mind 180 uses a smartphone/iPad app to control all its functions. The first version of the app didn't like OS 7.1 on my iPhone (it crashed on startup), but the latest version has been quite stable.
Another competing system is the Sony HAP-S1 music player ($995). The HAP-S1 has a built-in 500GB hard drive, as well as provisions to add an external USB drive. Unlike the Xi, the HAP S1 can't play USB memory sticks and can't stream from a NAS drive, but it can play 64x and 128x DSD files and 192/24 PCM files, none of which are supported by the Minx Xi.
If your Logitech Squeezebox is getting a bit long of tooth (Squeezebox products are no longer supported with new or updated operating software) or you want something more than a Sonos system, for $999, the Cambridge Audio Minx Xi offers features and sound quality that could be just what you are seeking. The Xi can also coexist comfortably in your domicile with other wireless systems and networks. During the review, I had a Sonos, Squeezebox, and Moon Mind all running happily in my home.
Sonically, the Minx Xi was quite impressive. Its resolution was so good that it was easy to tell the difference between 44.1/16 and 96/24 tracks that were sourced from the same DSD master. And, while the Minx Xi doesn't have the ability to play every single file in your library, it can play most with aplomb. I can see the Minx Xi being at the heart of a most excellent and quite flexible small-room system.