Review: Cambridge Audio Minx Air 200 and Minx Go Wireless Speakers Page 4
Frequency response: Minx Air 200
38 Hz to 20 kHz ±4.7 dB on-axis, ±2.9 dB to 10 kHz, ±5.1 dB avg 0-30°
Frequency response: Minx Go
108 Hz to 20 kHz ±3.5 dB on-axis, ±4.4 dB avg 0-30°
Bass output, Minx Air 200 (CEA-2010A standard)
• Ultra-low bass (20-31.5 Hz) average: NA
20 Hz NA
25 Hz NA
31.5 Hz NA
• Low bass (40-63 Hz) average: 106.3 dB
40 Hz 83.2 dB
50 Hz 104.6 dB
63 Hz 112.8 dB L
MCMäxxx™ maximum level test, Minx Go (1 meter)
To measure the quasi-anechoic frequency response of the Minx Air 200 and Minx Go, I set it them a 2-meter stand and placed the microphone at a distance of 1 meter directly in front of the left driver array on the Minx Go or the left BMR on the Minx Air 200. (Quasi-anechoic measurements eliminate reflections from surrounding objects to simulate measuring in an anechoic chamber.) I ran a ground-plane measurement at 1 meter on each unit to get the bass response. To create the graphs shown here, I spliced the bass response to the 0° on-axis response (blue trace) of the left channel only, and to the average of quasi-anechoic measurements (green trace) of the left channel only taken at 0°, ±10°, ±20°, and ±30°. I used a Clio FW analyzer in MLS mode for the quasi-anechoic measurements and log chirp mode for ground plane, feeding test signals into each devices's 3.5mm line input. The quasi-anechoic measurements were smoothed to 1/12th octave.
The Minx Air 200's frequency response is extremely flat through most of the audio range, from about 150 Hz to 7 kHz. The treble rolls off quite a bit above 8 kHz, probably because of the relatively large size of the BMR driver. Below 10 kHz, the on-axis and averaged off-axis responses measure very close, indicating very good dispersion through all but the top octave of the audio range.
The Minx Go's frequency response measurements are pretty good in the mids, too, looking smooth up to about 5 kHz. At higher frequencies, there are some larger dips and peaks in the response, probably due to reflections between the grille and baffle, and/or tweeter resonance(s). Off-axis response is very good, with just mild treble roll-off as you move off-center.
Every speaker of the Minx Air 200's size that I've tested can fill a room reasonably well, so I compare their "sonic muscle" by doing the same CEA-2010 bass output measurements I do on subwoofers. (Almost the same - I do the measurements at 1 meter because the bass output of most personal audio products isn't strong enough to do them at the usual 3 meters.) Averages are calculated in pascals per CEA-2010A procedure. In the low bass octave (40-63 Hz), the Air 200 beats the formerly class-leading B&W A7 by slightly better than 1 dB, at 106.3 dB versus the A7's 105.2 dB. However, while I was able to get measurable output from the A7 at 31.5 Hz and even a slight trace of output at 25 Hz, I couldn't get measurable output from the Air 200 at these frequencies.
For speakers of the Minx Go's size, the relevant test isn't their bass output - because they don't have any - but to what degree they can fill a room with sound. There's no industry standard measurement for that, but for more than a decade, I've judged max output of small devices using my MCMäxxx™ test: cranking up Mötley Crüe's "Kickstart My Heart" until it the unit hits max volume or it sounds harsh or distorted, then noting the maximum usable volume at 1 meter. With the volume all the way up, the Minx Go put out 90 dB in this test, which is +3 to +4 dB more than I usually get from compact Bluetooth speakers. Most such compact speakers are starting to sound a little rough (although still listenable) at the MCMäxxx volume, but the Minx Go sounded very clean even at full blast. - Brent Butterworth
The new portable lifestyle focus of the Minx series seems to be working out just fine for Cambridge Audio. Both of these products are clearly at the top of their respective classes, and well worth a long listen from anyone in the market for a wireless streamer for around the house (with the 200) or out of it (with the Go). Cambridge's strengths are evident in the voicing of both speakers - they're competitive in terms of horsepower with the best of what's out there, but they offer very smooth reproduction of vocals and acoustic instruments along with sheer volume. The radio features of the 200 (and the 100, not looked at here), along with the Minx app are a nice touch, though you might do just as well using the player of your choice on your computer or mobile device.
As I said above, it might have been nice to see a minimal onboard interface for the internet radio receiver on the 200, but that'd make for something of a different product. Just a thought... On the other hand, for the amount of clean sound it dishes out at a very attractive price point, the Go's a commendable product - a fine value proposotion in a saturated market of little Bluetooth devices.