Vivid Audio B1 loudspeaker
When John Marks wrote about the Vivid B1 in his column, "The Fifth Element," in February 2011, he was so excited about the sound he was getting that he asked me to drive up to Rhode Island to give a listen for myself. Not only was I impressed by what I heard at John's, I decided to do a full review of the speaker.
I first heard the B1 ($14,990/pair), Vivid's first product, when it was demmed at the 2004 London Heathrow show, but it didn't reach the US until the 2006 Consumer Electronics Show. The B1 is made in South Africa and engineered by ex-B&W designer Laurence "Dic" Dickie, who was responsible for B&W's original Nautilus loudspeaker.
I admit that I was put off by the Vivid B1's appearance. Some have compared it to a Zulu shield, others to a creation by H.R. "Alien" Giger. Perhaps it says something about my psyche that I found it reminiscent of something a little more, er, intimate. But after Vivid raised the weird-speaker stakes with the Smurf-styled G1 Giya, which Wes Phillips enthusiastically reviewed for Stereophile in July 2010, I started to like the look of the B1. And like the G1 Giya, its appearance is a case of form following function.
Drive-units get smaller as the range they handle rises in frequency, due to the fact that the wavelengths of those sounds also become smaller. Similarly, the optimal size of the baffle on which that drive-unit is mounted also decreases with increasing frequency. So while a nice wide baffle is ideal for mounting woofers, it is suboptimal for the midrange unit, and even less optimal for a tweeter. The B1's baffle therefore decreases in size as the drive-unit ranges increase in frequency, and this profile is echoed below the woofer to produce a vertically symmetrical shape. While it looks like a stand-mounted speaker, the B1's stand and base are integral parts of the enclosure. The enclosure material is polyester loaded with carbon fiber.
The B1 uses a 6.25" aluminum-cone woofer operating below 900Hz and loaded by a flared port below it on the baffle, a 2" aluminum-dome midrange unit to cover the range from 900Hz to 4kHz, and a 1" aluminum-dome tweeter. Though it therefore appears to be a three-way design, there is a second 6.25" woofer on the B1's rear panel, along with a second port. (The front and rear ports are in-lineyou can see right through the speaker.) The rear woofer increases the B1's dynamic range capability in the low end, but is rolled off above 100Hz, to minimize interference between the spaced drive-units in the midrange. The opposed woofers are driven in phase, and their chassis are connected to each other with a screw-tensioning bar so that any vibrational excitation of the enclosure is canceled. The tweeter and midrange unit are mounted on rubber O-rings, again to isolate them from the enclosure.
The drive-units used in the B1 were all developed by Vivid and are manufactured in-house. In their design, Laurence Dickie paid particular attention to the sound emitted from the rear of the diaphragms. The tweeter and midrange domes use radially polarized rare-earth ring magnets that present very little acoustic obstruction behind the dome. The dome's backwave fires into a large-diameter tapered hole in the pole piece, this attached to a fiber-damped, exponentially tapered tubein effect, an inverted hornthat runs the speaker's entire depth. As in a transmission line, the backwave from the tweeter and midrange domes is absorbed without reradiating back through the diaphragms. The woofer also uses a radially polarized rare-earth magnet assembly, this time with a diameter not much greater than that of the voice-coil, and the 12 struts connecting the cast frame to the magnet assembly are profiled to present the smallest possible surface area to the backwave.
The crossover filters are fourth-order and are connected to the two pairs of WBT binding posts in the base via wires that run through the struts of the integral stand. The base is fitted around its periphery with five removable spikes that can be adjusted for maximum vibrational coupling to the floor. There is no grille; the domes are protected by a skeletal crosspiece.
Once you get used to its idiosyncratic looks, the B1 is a stunningly beautifully finished speaker that incorporates engineering of equally stunning beauty.
My review samples of the B1 were the ones I had heard at JM's, finished in a smart Graphite (dark gray) gloss metallic paint. This much-traveled pair had been used at the 2010 SSI Show in Montreal, and had visited another reviewer on their way to JMand by the time they arrived here, the 50mm midrange dome of one speaker had been destroyed in shipping. Vivid shipped me a replacement assembly of dome, voice-coil, and magnet, with which I replaced the damaged one. The entire assembly screws into the tapered transmission-line tube, which is then securely fastened to the enclosure's rear with a crosshead bolt. I took before-and-after measurements of the damaged speaker, as well of its undamaged sibling, so that I could be sure that my repair job hadn't compromised the B1's sound. After the repair, the two samples matched extremely closely: within 0.5dB throughout the region covered by the replaced unit.
Setting up the speakers was more difficult than usual, in terms of getting smooth integration of the mid- and upper-bass regions and the midrange. At first I was getting rather "puddingy" low frequencies that sounded a little isolated from the speakers' upper ranges. Moving each speaker half an inch at a time, from side to side or forward and backward, I ended up with a balance that sounded smoothly blended from the midbass up. Each speaker's front woofer, which is 32" from the ground, ended up 80" from the wall behind it and 48" from the nearest sidewall, though the first 15" of that wall comprises record cabinets and bookcases. I toed in the speakers to my listening seat and, once I'd optimized those positions, fitted each base with the five carpet-piercing spikes.
The Vivid's low-frequency character was vulnerable to cable changes, added to which was the fact that the two pairs of speaker terminals are under a lip at the rear of the base, which complicates the use of stiff cables fitted with spade lugs: There just wasn't enough clearance for the AudioQuest Wild cables that I'd been using up to the B1s' arrival. I tried Audience's Au24 e cables, which Brian Damkroger highly recommends, and which have 4mm connections rather than spades and are thin enough to be easily dressed. However, even with the Classé CT-M600 monoblocks, which have superb bass control, these sounded too warm. I ended up using a single pair of Cardas Neutral Reference speaker cables, which John Marks recommended a few issues back. These have terminating pigtails flexible enough to fit into the limited space that was available, and I connected the two pairs of terminals with the shorting straps provided by Vivid.