September
2020

Country of Origin

France

M Zero Junior

Reviewer: Srajan Ebaen
Financial interests: click here
Main system: Sources: Retina 5K 27" iMac (4GHz quad-core with Turbo boost, 32GB RAM, 3TB FusionDrive, OSX Yosemite. iTunes 14.4), PureMusic 3.02, Audirvana 3, Qobuz Hifi, Tidal Hifi, Denafrips Terminator, Soundaware D300Ref SD transport & USB bridge; Preamplifier: Vinnie Rossi L2 Signature with WE VT52/300B or Elrog 50/300B; Power amplifiers: LinnenberG Audio Liszt monos; Headphone amp: Kinki Studio; Headphones: Final D8000; Loudspeakers: Audio Physic Codex; Cube Audio Nenuphar; Aurai Audio M1 [on loan]; Cables: Complete loom of Allnic Audio ZL3000; Power delivery: Vibex Granada/Alhambra on all source components, Vibex One 11R on amps, LessLoss C-MARC Entropic cords between wall and conditioners; Equipment rack: Artesanía Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands; Sundry accessories: Acoustic System resonators; Room: 4 x 6m with high gabled beam ceiling opening into 4 x 8m kitchen and 5 x 8m living room, hence no wall behind the listening chairs
Second system: Source: Soundaware D100Pro SD transport; DAC/pre: COS Engineering D1; Amplifier: Bakoon AMP-13R; Loudspeakers: Acelec Model One w. Franck Tchang magnesium 360° super tweeters, Zu Submission subwoofer, LessLoss Firewall for Loudspeakers; Power delivery: Puritan Audio Lab PSM-156; Equipment rack: Hifistay Mythology Transform X-Frame [on extended loan]; Room: ~4x6m
Desktop system: Source: HP Z230 work station Win7/64; USB bridge: Audiobyte Hydra X+; Headphone amp: COS Engineering H1; Headphones: Audeze LCD-XC; Powered speakers: Fram Audio Midi 150
Upstairs headfi system: Source: Soundaware A280 SD transport; DAC: Auralic Vega; Integrated amplifier: Schiit Jotunheim R; Headphones: Raal-Requisite SR1a
2-channel video system: 
Source: Oppo BDP-105; DAC: Kinki Studio; Preamp: Wyred4Sound STP-SE II; Power amp: Pass Labs XA-30.8; Loudspeakers: German Physiks HRS-120; Room: ~6x4m
Review component retail ex VAT: €9'000/pr satin cherry, €9'500/pr high-gloss rosewood

First M Zero Junior shown next to an M1 for size reference.

From zero to hero?
Zero means… well, nothing.

Then why call a speaker Model Zero?

Excellent question.

It's answered if its designer starts from nothing. If he rethinks the entire game. Carte blanche. Tabula rasa.

Alas, give some designers carte blanche and you might as well hand them an unlimited American Express Centurion card. They'll spend silly money to end up with a monstrosity not even a mother could love.

If you're Alain Pratali, otherwise retired savant in southern France's Marseilles, your carte blanche is stamped sanity. Now your proof-of-concept Zero measures just 110cm tall on a 41x55cm WxD foot print.

Top to bottom, it runs a dipole ESS AMT with a dipole Supravox paper-cone widebander. Hidden insideworks a 11.8" AudioTechnology woofer. Bandwidth is a sensible 35Hz to 22kHz, sensitivity a true 94dB.

But what if that zero is still too big?

How about half a zero? Hello Zero Junior.

It scales the concept down. The tweeter now is Alain's proprietary sub 0.12g polyester dome we already met in the M3 and M1 models. It's based on a Western Electric 555 motor with floating 2-inch Altec diaphragm. It loads into a precision-machined ellipsoidal Delrin horn which here turns into a Laurence Dickie-style tapered tube hovering like a katana display above the enclosure.

"For Zero Junior, I was no longer forced to put the tweeter on the same vertical baffle as the mid/woofer which I had to do for the M1 and M3 to simplify their constructions. Now Junior's set-back tweeter pod corrects for the 0.3ms time offset."

The Supravox paper-cone widebander operates in dipole mode again so the box opens to it behind a grill in the back. Whereas the M Zero's woofer vents through three slot ports in the front, Junior moves those slots to the rear.

That begs questions. Is this a ported bass alignment? A TQWT? A transmission line? A hybrid?

"When I began the project, I started from scratch. I wanted to merge the very best I had ever heard as both an engineer and audiophile. A parallel goal was to make a small speaker, not a giant like we currently see them in magazines. So the Zero Junior is just 115 x 30 x 47cm and weighs 42kg."

"To get serious, let's be clear. We don't have 1001 options. There's the closed box, open baffle, bass reflex, quarter wave tuning, band pass and all variants on resonant bass circuits with twin impedance peaks. I've heard them all and tried everything. It turns out that a 4th-order symmetrical band pass gives me bass that's very elegant and fast. It's my greatest listening satisfaction in the low registers. So that's what I pursued for the range of 30Hz to maximally 125Hz. The woofer chamber is sealed, a vented chamber fronts it."

Here's a video which Alain considers a very good presentation on the subject even though he also disagrees with the presenter.