Platinum Audio Solo loudspeaker
By John Atkinson   •   November, 1995 Flip flip flip]...Where the heck is it?...[flip flip flip]...Got it!" What am I looking for? There, in black and white, on p.634 of J. Gordon Holt's Really Reliable Rules for Rookie Reviewers (footnote 1), is the Prime Directive On Loudspeaker Setup: "Never, ever, choose a loudspeaker that has too much bass extension for your room!"

Time and time again I get letters from readers who have relatively small rooms asking why they can't get an even tonal balance from their [insert brand-name of massive, flat-to-20Hz behemoth here] speakers.

The answer is a no-brainer: If you have only a small room, the "best" loudspeaker will almost always be one with limited low-frequency extension. Not only will this reduce the amount of excitation given the lowest room resonant modes; the effect of the boundaries in a small room will actually increase the amount of bass. In such circumstances, a minimonitor will actually give better, more neutrally balanced low frequencies than a full-range design. The latter will produced an exaggerated LF response that might be seductive in the short term, but over the long term the incessant boom will prove irritating. And in the small room, the need for massive sound-pressure levels does not mandate equally massive loudspeakers.

Which is why in my relatively small room—irregular in shape, it basically measures 19' by 16.5' by 9'—I have used small speakers as my long-term references: Celestion SL600s and '700s, Rogers LS3/5as, Harbeth HL-P3s, Epos ES-14s, Thiel CS2 2s (okay, the Thiels aren't so small), and most recently, B&W John Bowers Silver Signatures (footnote 2). Despite their modest size, the Silver Siggies fill the room with an astonishing amount of low frequencies, flat down to 33Hz or so—as long as you don't play them too loud.

I'm always on the lookout, therefore, for small speakers that will rival the B&Ws in transparency, midrange neutrality, and soundstaging, but that kick big booty when it comes to playing loud and proud.

Solo
The $2497.50/pair Solo is the smallest in the debut range of loudspeakers from Platinum, a new New Hampshire company founded by loudspeaker engineer Phil Jones. Jones, whose track record includes stints at Acoustic Energy and Boston Acoustics, has long been involved in the quest to get high, distortion-free sound-pressure levels from small speakers. He was a pioneer in the reinvention of the metal-cone woofer in the mid-'80s; the acoustic notch filters to be seen in front of the tweeters in Boston Acoustics' Lynnfield-series speakers were also his idea.

The Solo appears to be a fairly conventional-looking, reflex-loaded two-way mini. It features a metal-cone woofer with a radiating diameter of about 4", this terminated with a rubber half-roll surround. The cone has some concentric rings molded into it. Mounted above the woofer on the front baffle is a 1" tweeter, with a protective "phase-plate" in front of the metal dome. No frequency response is specified, Platinum saying that "The industry standard is to publish frequency response data based on anechoic chamber...measurements. We don't know anyone who listens to music in this environment. Frankly, it sounds dreadful." The 1995 Audio Equipment Directory, however, lists 40Hz–20kHz, ±3dB, which is fair considering the Solo's size.

The cabinet rear- and side-walls are finished in an attractive wood veneer, with the top and bottom panels high-gloss black. These are radiused at the front and overlap the front baffle by up to an inch at the center. The black wire-mesh grille has foam inserts to try to minimize reflections from these acoustic obstructions. The crossover is carried on the inside of a heat-fin–equipped black metal panel inset into the rear panel. This also carries at its top the flared openings for the two 1.5"-diameter reflex ports. One is 6" deep; the other is blocked with foam 4" in.

The black-crackle–finished Platinum Pedestals are similar to the very expensive Acoustic Energy stands but use flat steel bottom and top plates. Two steel cylinders are filled with lead shot (recommended), or a mixture of lead shot and sand (which is what I used). The result was acoustically inert. Four knurl-grip spikes can be adjusted from above to level each ca 25"-high stand and prevent it from rocking. The speaker can be coupled to the stand top plate with rubber feet, cones, or bolts.

Sound
After some experimentation, the Solos were placed on their stands in what turned out to be pretty much the same positions as the Acoustic Energies, well away from the room boundaries. The stand puts the speaker's tweeter 36" from the floor, this listening height recommended by Platinum in their handbook. I experimented with both the rubber feet and the optional cones to couple the Solo to the stand top plate. It was the cones that stayed, the sound losing out on maximal clarity with the compliant feet. (Your sonic mileage may vary.) With the cones, the speaker and stand were as solid and inert as a rock.

Before I get well stuck into a discussion of the subtleties of the Solos' sound, you have to understand one thing: Phil Jones is a bass guitarist. Oh, and a second thing: so is his partner in Platinum, Geof Bates. Both are aficionados of the thunder-thumbed, lightning-licked power-plucking techniques endemic among thoroughly modern bassists. When you hook up the speakers and reach for a record from the Brothers Johnson, or Larry Graham, or Bootsy Collins, the Solos sing'n'swing in the lows. "All that bass coming from those little boxes?" was a common reaction to the pint-sized Platinums.

One of the reasons I wanted to include the Airto Moreira and the Gods of Jazz track "Nevermind" (from Killer Bees, B&W Music BW041) on Stereophile's Test CD 3 was to pay tribute to bassist Stanley Clarke. Stanley's double-bass solo on this track may be recorded close, but I think it's the best-recorded jazz double bass I've heard—round, deep, enveloping, and powerful. And on the little Solos, that's what I heard. A suitably big sound from a big player.

To give you an idea of what the Solos could do, track 11 on the East River Drive album (Epic EK 47489), "Lords of the Low Frequencies," features Armand Sabat-Leco thunderously a-poppin' and a-slappin' on his electric bass beneath Stanley Clarke strumming his tenor instrument. With the Levinson '38S and '333 cranked, the Solos could take a full 23V RMS on this transient-rich track, shaking the room with spls in the mid-90s, the twin ports a-huffin' and a-puffin,' the woofers blurring with what seemed like one whole inch of peak-to-peak excursion. One more click on the volume control (footnote 3)...and the little woofers cracked against their end-stops, and I dived for the mute button! Awesome! All this from two 4"-diameter woofer cones!

And even on albums featuring less virtuosic bass playing, the Solos pointed out details in the playing that you hadn't appreciated on other smaller speakers, like LS3/5as. I have recently been getting into Jimmy Webb's patchy 1993 album Suspending Disbelief (Elektra 61506-2). This was produced, I found to my surprise, by Linda Ronstadt and George Massenburg and recorded, in part, at Skywalker Ranch. The opening cut, "Too Young to Die," features the familiar, big ol,' comfortably fatback tones of session bass player Leland Sklar—and don't his understated root notes just underpin the song's melodic suspensions beautifully. (Check out David Crosby's, Don Henley's, and J.D. Souther's combined pipes in this track's backing vocals—pure California vocal heaven!)

There's a price to pay, however, for this big-bottomed purr-formance. (Isn't there always?) To get such impressive low-frequency extension from a small box, the designer has had to sacrifice sensitivity—the Solo doesn't play too loud on a diet of a volt or two—and the bass alignment is pumped up, at the expense of absolute definition. Stanley Clarke's "Africa I'm Home" from East River Drive, for example, may have had more low-end grunt on the bass guitar with the Solo than the Acoustic Energy AE2 Signature that I also review this month, but it was noticeably less tight. In absolute terms, it was on the point of becoming boomy. Fortunately, in my room and my system, the Solo remained on the just-acceptable side of gloom'n'boom, but this is something you'll need to check for yourself.

Okay, okay—you want to hear about the audiophile aspects of the Solo's sound. Time for some classical music. The Don Was–produced Brian Wilson documentary, which I caught both on PBS and on BBC-TV on a recent trip to the UK, triggered a trip to the CD cupboard to drag out Surf's Up. Others may point to Pet Sounds as the climax of the Beach Boys's oeuvre, but for me it's the combination of Brian's music and Van Dyke Parks' dense lyrics on the title track, along with Carl's impressive first attempts at large-scale production on "Feel Flows" and "Long Promised Road," and Bruce Johnston's immortal "Disney Girls" that defines the mature Boys. (I draw a discreet veil over Mike Love's "Student Demonstration Time.") Surf's Up was also the first album I heard on a full-blown quadraphonic system.

The Solos threw a well-defined soundstage, every little bit of filigree detail oh-so-carefully layered into the mix—the pealing glockenspiel, the "Wipe out, wipe out" backing voices, the trumpet, the ostinato tambourine, and the climactic "Child is father to the man" closing—clearly positioned in space. Yes, the presentation was overall a little laid-back—you shouldn't play the Solos quietly. But the lack of midrange coloration, coupled with excellent clarity, allowed little details—like the different quality to Bruce Johnston's pure high tenor in the second half of "Disney Girls" compared with the first, for example—to be easily perceived, yet without them being thrown forward at the listener.

And on real classical music, the Solos created the same illusion: of the listener being transported into the recording space. My George Szell Beethoven "Pastoral" (Sony Essential Classics SBK 46532) never sounded so real. (Well, almost never. The B&Ws and Acoustic Energies still scored big-time here.)

But I couldn't forget the Solo's lows. I finished up my auditioning with a couple of newly acquired CD singles from Sting (This Cowboy Song, A&M 580 957-2, and When We Dance, A&M 580 847-2). These feature four very different deconstructionist, hip-hop–flavored mixes of "If You Love Someone," both with massive synth bass lines. The Solos turned my room into a miniature disco, even though the little woofer cones at times looked as though they were going to jump out of the magnet gaps.

Cary On
Partnering the Platinums with the single-ended Cary CAD-300SEI tube amplifier didn't prove a success. The loudspeaker just needs more watts than the Cary can provide to come alive. And though the midrange magic was there, the tube amp just couldn't hold onto the Solo's bass. The bass lines in the Sting tracks, for example, blended into a low-frequency roar. Sorry, SE fans—the Solo can only be satisfied by solid-state.

Conclusion
The Platinum Solo is a must-audition speaker for the bass-lover with a small room. Yes, it does need a lot of amplifier watts to come alive; and yes, at a hair under $3000/pair with its essential stands, the perceived value is on the low side; and yes, it will need careful matching with the room and system to avoid excess midbass bloat. But when everything floats its way, the Solo is a serious contender. Recommended—Platinum's Solo is a great start for a new speaker company.

And for you fellow bass players out there: If Phil Jones can do this with a woofer with a 4" cone, what will the bass-guitar speaker he's working on be capable of? Warn your neighbors—and their neighbors!

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Footnote 1: Published in 190 parts, starting in November 1962.

Footnote 2: I use the Silver Signatures with the tweeters on the inside edges of the baffles—ie, away from the sidewalls—and toed-in to the listening position. This, to my ears, gives the smoothest transition through the crossover region. I have also been able to improve their definition in the lower mids by weighing them down with a small bag of lead shot draped over the top rear of the cabinet.

Footnote 3: Or leaving the CD playing at the same volume until the opening kick-drum blast on the next track!