Monitor Audio Bronze BX1 Bookshelf Speaker
More than any other speaker in this group except perhaps the Polk, the BX1 ($379/pr) looks like a high-end product, with its walnut finish; its 1-inch, gold-finish C-CAM (composite ceramic metal) tweeter; and its 5.5-inch C-CAM woofer. Unusually, the woofer is attached to the back panel, not the front, so its vibration won't be as easily transmitted to the front panel. The BX1 includes a foam plug for its rear port that lets you convert it to sealed operation for use near a wall. (We listened to the BX1s with their ports in the "unplugged" state.)
Over and over, the panelists described the BX1's sound as "flat," but they meant that as a compliment. They meant flat in terms of frequency response, i.e., without any peaks and dips that color the sound. "This is an all-around good speaker," Lauren said. "It works really well on rock, pop, acoustic music … almost anything." I felt that the BX1's tweeter was definitely the best in this bunch, the only one that showed not a trace of edginess. It was also in perfect balance with the woofer; Monitor's engineers nailed the crossover on this one.
The BX1 exhibits that open, ambient sound for which minispeakers are known, although Greg and I both felt that the soundstage size seemed slightly exaggerated. Geoff and Lauren both pined for a little more bass, but never complained that the BX1 sounded thin.
When I listened to the BX1, I was reminded of the experience I've had listening to HiFiMan's excellent HE-500 planar-magnetic headphone, which has a neutral sound that treats any kind of music with respect. If that's what you want, the BX1 will give it to you. If you prefer the more hyped-up sound of, say, Beats headphones, the BX1 might bore you. As for us, we'll take flat over hyped any day.
Frequency response of the BX1 measures 85 Hz to 20 kHz ±4.5 dB on-axis, ±4.6 dB avg 0°-30°. That's pretty flat, but there's a very mild downward tilt in the treble. Measured impedance is 3.4 ohms minimum, 5 ohms average. Sensitivity from 300 Hz to 10 kHz averages 85.7 dB.