August 2020

PureAudioProject's Quintet 10 Open-Baffle Loudspeaker Review
Look ma, no boxes! I spent 100 days and nights with PureAudioProject's Quintet 10 open-baffle speakers — and found that they are sonic shape-shifters of the highest order.
Review By Rogier van Bakel

  "Audiophile" and "oenophile" don't just sound similar. The words have this in common too: they describe a world where subjective judgments of quality must rule without a chance of different opinions being resolved. After all, no one can make valid generalizations about what the ideal power amplifier or the perfect pair of speakers sound like — any more than a wine lover can claim with universal authority that a bottle of 1979 La Mission Haut Brion is better than a 1988 Château Léoville Barton, or vice versa.

Wine connoisseurs and hifi purists also both live in a place where arcane knowledge is routinely flaunted, and where descriptions can get so florid as to invite parody. Someone actually gifted me a 1978 bottle of that above-mentioned Léoville Barton recently, and when a friend inquired in an email what it had tasted like, I parked my tongue firmly in cheek, and replied,

"I beheld Hawthorn berries and beef stock along with a suggestion of blonde tobacco. Other than the obvious green walnut, there was a top note of wet Baja beach at dawn, subtly mixed with minke-whale flatulence and a hint of two-day-old scallop innards. Finally, with subsequent sips, I also detected burnished saddle leather — blending, after a second or two, with the aroma of the well-worn merkin of a Honduran sex worker of indeterminate gender. All in all, not a bad wine."

Of course, I write audio articles that stay away from such preciousness, but I will say that the PureAudioProject Quintet 10 speakers inspired some unusually flowery musings in my listening notes, as well as a certain frustration with capturing their essence in words. That's because the Quintets are consummate sonic shapeshifters. More on that in a minute.

First, let's look at outward appearances. The Quintet 10s are a product of out-of-the-box thinking — literally. Open-baffle dipole speakers intended for medium- to modestly-large-sized rooms, they stand 5' 3" tall, and measure 16.5" wide. The curvilinear design (arched away from the user) time-aligns the drivers for the listening position. The panels, which can be ordered in white, black, red, a chic blue-gray, bamboo, German oak, and various custom finishes, are mounted on vertical rails rising from a black metal base that tapers to a triangle in the back.

This is where the Thrier modular crossovers are mounted — out in the open, which means that owners with inquisitive pets or toddlers might want to keep an eye on their playful darlings. Of course, neither the crossovers nor the multiple dangling Klotz speaker cables that connect all the drivers are visible from the front, not even at fairly extreme toe-ins.

At 56 pounds each, and just inches thick at the sides, the speakers aren't hard to pick up and move around, especially if you slip one foot under the base to help lift them.

The Quintets have a modern look — to my eye, even a bit industrial — that, in white, stood out in my relatively traditional listening room. They would have no problem blending gracefully into a contemporary décor.

Each speaker accommodates four 10" OB-M10EXT woofers, which PureAudioProject says are handcrafted by Morel, "based on a field-proven chassis but modified for open baffle and specifically our speakers." Together, these bass drivers can reach down to 29Hz.

Now, why did I call the Quintet 10s "sonic shape-shifters"? For starters, their mid-high drivers can be swapped out in a matter of minutes, according to the owner's preference. My review sample of the Quintets included, for the central panel, an 8" dynamic German-built Voxativ driver (claimed to be full-range), as well as a new proprietary 9.5" round compression-horn driver that the folks at PureAudioProject have dubbed the Horn2. Instead of these, or in addition, buyers can also order the "Stellar" panel, which combines Morel's well-regarded soft-dome tweeter and a carbon mid-range driver. I didn't evaluate this option, and listened to the Quintet 10s with, alternately, the Voxativs and the Horn2s installed.

Beyond the ability to fine-tune the sound by switching crossover components, the open-baffle design means that the crossover on each speaker is easily accessible. Thus, bliss awaits inveterate tweakers who arm themselves with a Phillips-head screwdriver and different capacitors and resistors. I achieved the most satisfying results with the horns and a pair of PAP-supplied Mundorf MCAP EVO Silver/Gold Oil capacitors, which sounded quite a bit better to me than the twice-as expensive Supreme Silver Gold Oil caps that PureAudioProject also allowed me to try. The change between the two was not subtle, beginning with an increase in palpability. As I wrote to PAP founder Ze'ev Schlik, after I installed the more affordable caps, I could literally hear the difference from the next room. "Everything seems louder," I told Ze'ev. "I don't know if that's actual dBs or just the general presentation where the Quintets come out of their shell a bit more, shedding their reticence. Bass goes deeper, or seems to anyway. Why is that? I'm no longer tempted to switch on my subwoofer for deep-bass tracks."

He wasn't a bit surprised (the less-pricey caps are his favorite, too): "The reason is that every low note of the bass consists of its main frequency and an infinite number of harmonies that are multiples of the main frequency. Once the harmonies are reproduced with greater clarity, the overall sound of the bass clears up."

I'll take it.

There's also a small jumper on the crossover board that has two positions; moving it boosts or attenuates the highs a bit.

It's good to have all these options, even if it did complicate my job as a reviewer — and not just because I spent perhaps too much time on my poor knees in the cramped space behind the speakers, moving jumpers and swapping resistors and capacitors. (Audiophiles who resent their own tendency to endlessly futz with the variables in their audio system will find these speakers a challenge.) In the end, with all the changes I made, and the resulting differences in sound, it felt like I'd been reviewing four, five pairs of speakers, instead of just one. The following assessment of the Quintets 10's many strengths — and one or two apparent weaknesses — is based on the common denominators I found between these different "voices" over the 100 days and nights I spent with the speakers.

Without fail, in my 3300-cubic feet, moderately-dampened listening room (drywall, hardwood floor, three sizable rugs), the Quintet 10s reproduced music that sounded open and extraordinarily dynamic, with often strikingly accurate timbres. I realize this seems almost too cute, but the speakers with the Horn2s installed made especially clarinets, trumpets, trombones, and other wind instruments sound hyper-realistic. Playing Sketches of Spain on the Quintets conjured a mid-career Miles Davis right there in my room, almost 60 years after the fact. I was frequently startled — and chuffed — by this time-machine-like quality.

The Quintet 10s are also beautiful with cellos and piano. Listen to Stephen Emmer's terrific new album — the introspective, Satie-meets-Sakamoto Maison Melody — for a generous taste of both.

On the other hand, massed strings can sound incisive and strident when they move into the higher register; but for such recordings, the treble-attenuating jumper in the back easily corrects things. I found this to also be true with the heavy bell that's struck in the chorus of Nick Cave's Red Right Hand. In my room, the Quintet 10s seemed to generate too much energy in that frequency band, but moving the jumper tamed the harshness without further fuss. I left it in the attenuated position for the rest of my time with them.

The speakers are very resolving, with gobs of inner detail, but I never found them etched or fatiguing. Remarkably, with the Horn2s and the Voxativs alike, the Quintet 10s rendered transients fast enough to rival my beloved MartinLogan Odyssey electrostats.

Here are a few tell-tale snippets from my listening notes:

"Donald Fagen's guitar solo on The Goodbye Look is beautifully crystalline. ... John Hammond on Murder in the Red Barn sounds perfect. Damn, that acoustic bass is solid, and so is the snare. These speakers like blues. And they swing. Exemplary timing."

"The electric bass is really fine and meaty on Aretha Franklin's Rock Steady. Good imaging too! And percussion? Stellar."

"Both male and female vocals come through in a way that, in terms of intelligibility, approaches headphone listening. You can concentrate on the lyrics and actually follow lyrics sung even by mumbly vocalists."

"My German shepherd is impressed. When I just played Lionel Loueke's Tribal Dance, which starts with polyrhythmic breathing, he pricked up his ears and comically tilted his face this way and that, the way canines do when they hear unexpected sounds they think are real. I've played that recording many times, and I'd never seen the dog do that before."

I have pages and pages like that, but there were instances when the note-taking stopped. One night, in a frenzy of unplanned eclecticism, I jumped around according to the whim of the moment, from Duke Ellington to the Dukes of Stratosphear, from Los Lobos to Los Cubanos Postizos, from John Prine to John Lurie. Soon, I was beyond listening for anything veiled or forward or smeary or bright. Apologies for my dereliction of duty, but I got so busy enjoying all that sonic art that the scribbling stopped and the grinning and toe-tapping took over. To hell with the review, my id said — and when you think about it, that's a seriously big compliment for the speakers. On and on the musical trip went. Paquito d'Rivera. Bonnie Raitt. Susana Baca. Bill Frisell. Blood Orange. Kansas Smitty's. Fantastic Negrito. The Punch Brothers. Renaud Garcia-Fons. Lil Peep. Black Uhuru. Melody Gardot. John Martyn. All thoroughly enjoyable. The Quintets sounded pristine when cleanness was called for, and appropriately dirty when grittiness demanded prominence.

Then it was 5 a.m., the level of the bottle of Knob Creek had gone down precipitously, and it was finally time for bed. I slept like a baby.

When I regained my critical mind, did I hear any negatives? Rarely. Yes, there was a bit of dryness in the snare drum on Dire Straits' Six Blade Knife, and I became aware of the same thing on Marcus Miller's Pluck. But it's hard to say what was happening there, because when I switched to percussion-heavy tracks like those on Mickey Hart's Planet Drums and Zakir Hussain's Dances With Wood, all sounded supreme again across all frequencies. So did the fantastically engineered and produced Song of the Stars by Dead Can Dance. Not all recordings are created equal. Nothing new there, I suppose.

Two final things. The Quintet 10s, in my experience, are not the world's greatest speakers for low-level listening. They like volume (and amplifier power) to strut their stuff. If you're listening late at night and you have sleeping housemates or not-so-understanding neighbors, you might want to use headphones, or choose speakers that reveal the sum of their talents at modest listening levels.

On the other hand, the Quintets won't wake anyone with foundation-shaking bass. They dig more than deep enough for all but reggae, full-bore symphony recordings, and pipe-organ music — genres where low-end energy hitting you in the stomach is part of the experience. Ninety-eight percent of the time, I was very happy with what I heard; the other two percent, when my basshead tendencies craved feeding, I switched on my Canton 12.3 subwoofer and thought no more of it.

The Quintet 10s were a prized presence in my home. Like the best of guests, they were unobtrusive, but unfailingly generous with their grace and charm — and ready to party at a moment's notice. I'd welcome the pleasure of their company anytime.

Specifications
Type: Type: Open baffle loudspeaker

Drivers: Eight 10'' Morel OB-M10EXT woofers (four on each speaker), combined with 9.5" wooden compression horns, or 8" full-range Voxativs, or a combination of a Morel soft-dome tweeter and a Morel carbon midrange driver.

Crossover Type: PureAudioProject Thrier, two-way first-order series or parallel topology.

Nominal Impedance: 8 Ohms

Frequency Response: ~29Hz–20kHz

Sensitivity: 89 to 91 dB/W/m (depending on the room)

Dimensions: 63" x 16.5" (H x W)
                  Depth is mere inches, depending on where you measure.

Weight: 56 lbs per speaker

Price: $7990 or $8490 per pair depending on configuration, including shipping.
In Europe €8490 or €8990, including VAT and shipping.

Company Information
PureAudioProject
Voice: (877) 927-2233
Europe: +49 69 2991 7675
E-mail: info@pureaudioproject.com 
Web: www.PureAudioProject.com