Totem Acoustic Forest loudspeaker John Atkinson, April 2010
The floorstanding Forest loudspeaker ($3495/pair in black ash or mahogany) from Canadian manufacturer Totem Acoustic5 has been highly recommended by Stereophile since it was first reviewed by Larry Greenhill in April 2001. My comments on the Forest were published in September 2005, and as a result of LG's and my experiences of the speaker, it was consistently recommended in Class B (Full-Range) of the magazine's biannual "Recommended Components" feature. I also mentioned the Forest in my October 2006 "As We See It" essay.
Last summer, I asked new reviewer Erick Lichte to give a more recent pair of Forests a listen; his Follow-Up review was published in January 2010. While Erick liked much of what the Forest did, overall he was less impressed than Larry and I had been. "When I touched the cabinet of a Forest while playing them at even moderate volumes," he wrote, "I felt a whole lotta shakin' goin' on; those cabinets 'sang along' with the music more than I'm used to. . . . During his listening in 2005, JA set bags of lead shot atop the Forests in hopes of taming that liveliness. . . . I can't help but think that the Forests' lively cabinets impede their ability to image as well as they otherwise might."
Erick expanded on the subject of the Forests' stereo imaging: "One aspect of the Forests that LG commented on in his original review," EL wrote, "was their ability to throw a large soundstage. But while the Forests' imaging greatly improved with the addition of ballast, I never got them to create the truly holographic soundstages LG wrote of. Sound tended to lump up around each speaker instead of being spread evenly between them." Erick concluded that the Totem Forest offers a "smooth midrange, airy treble, and well-extended bass in an attractive, compact package. If you audition them or already own a pair, make sure their bottom cavities have been filled with sand and/or shot. . . . However, $3495 is a fair chunk of change for a pair of speakers, and there are many fine contenders at or near this price listed in Stereophile's 'Recommended Components.'"
Erick's Follow-Up was a fair, balanced report from a writer who had done his best to get the best from the speakers, I feel. However, because of conflict between his findings and Larry's and my feelings about the Forest, and because his conclusions would downgrade the Forest's rating in "Recommended Components" to Class C (Full-Range), I asked EL to ship the review samples to me, so I could both listen to and measure them, to see if the pair matched one another, and if they measured any differently from the previous two pairs we had reviewed.
Well, so much for good intentions. When I unpacked the Forests, one of the pair, serial no. PM4002, had a woofer that wouldn't moveits voice-coil was frozen solid in the magnet gap. This fault generally stems from an amplifier putting out DC, or from a massive thump from, say, turning a singled-ended preamplifier on or off with the power amplifier powered up. This had happened to me during my auditioning of the Sonus Faber Cremona Elipsa loudspeakers, which I reviewed in December 2007. Unknown to me, my Benchmark DAC1 had broken and had 15V of DC riding on its output. When I turned on the Parasound Halo JC 1 amplifiers, they did their best to amplify this DC, and before their protection cut in, all four of the Elipsas' woofers had leapt forward and then frozen in that position.
The Totem's broken woofer raised two issues. First, how had this happened? Erick uses a Benchmark DAC1 fed directly to the amplifier, which, in the case of his Forest Follow-Up, were two Rogue M180 monoblocks, a Manley Stingray iTube, a Pass Labs XA30.5, and a Pass Labs Aleph 3. The tubed Rogue and Manley amps use output transformers, so can't pass DC; nevertheless, I asked Erick to measure the DC offset on all four amplifiers, as well as on the Benchmark.
Each had a clean bill of health. The Pass Aleph 3 had 1mV of DC on both its outputs, the other amplifiers about the same. The Benchmark had around 7mV on its output, which, when amplified by a DC-coupled power amplifier, is not enough to do anything other than move the woofers' voice-coils a little way away from their central, rest positions. I also checked the amplifier I use for the speaker measurements; this had around 20mV of DC on its output, which is negligible. So the frozen woofer was probably not the result of an amplifier going bad.
Then I remembered that Erick had filled the cavity at the base of each Forest with clean, dry, sand. This both mass-loads the speaker and helps tame the enclosure's resonances. Before shipping the Forests to me, EL had tipped the speakers every which way to try to get all the sand out, then vacuumed up what was left. Even so, when I unpacked the speakers, a small amount of fine sand was trapped in their plastic bags. We conjectured that perhaps stray grains of sand had found their way into the woofer's voice-coil gap.
Though I thought this possibility smallwoofers tend to be quite well sealedI nonetheless removed the woofer, which is held in place by 12 (!) hex-head bolts. I saw no sand sticking to the outside of the woofer, so obviously, even if sand had gotten into the cabinet, it wasn't magnetic. I couldn't dismantle the woofer itself, but as it wasn't possible to move the coil at all, even by rocking it at the spider, I suspect that it had indeed been fried by a DC overvoltage. If sand were fouling the gap, I'd have at least been able to rock the coil, however slightly; but it was frozen solid.
So we were back to the DC hypothesis, in which case the question is: When did this happen? I asked Totem's Lucy Lentini if the Forest samples Erick had written about had come straight off the production line, or were loan stock that had previously been used by someone elseand, if the latter, if they'd gone through Totem's regular quality-assurance procedure. (If the review samples weren't new stock but had come to us from, say, another reviewer via the factory, it may well have been that one of the woofers was damaged, but didn't finally give up the ghost until EL had used it for a while.) Lentini responded that EL's review samples had previously been loaned to a few dealers, but had passed a factory listening test before being shipped to him.
Though Erick confirmed that both Forests had been working fine when he installed them, he reviewed his listening notes to see if they might reveal any sudden degradation in the speakers' sound. However, he was adamant that both woofers were working properly during his formal auditioning period; in fact, one of EL's last tests with the Totems was to drive them hard with Kanye West's "Love Lockdown," from 808s & Heartbreak (CD, Roc-A-Fella/Def Jam), and listen to the ports of both speakers for any audible chuffing. He reported to me that, even with this bass-heavy cut, both woofers and ports were operating. In short, his review comments are valid as published.
The cause of the frozen woofer must remain a mystery, therefore. However, Erick had kept the Forests in his system for a few weeks after submitting the review, using them for background music. If, during this time, they had experienced enough DC to wipe out a woofer, he probably wouldn't have noticed.