6moons audio reviews: A 4-year journey into open baffles with widebanders

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Contributor: Lance A. aka Chopper87 on the forums

Various OBs in various states of finish, my Medallion horns in background.

My beloved Chartwell LS3/5a.

A four-year open baffle journey arrives at two simple yet world-class OBs: All these many years I’ve been trying to build the perfect system. More often than not, this centered around speakers. Having been in the business of professional and domestic audio sales for more than ten years—mid 1970s through mid 1980s—afforded me the opportunity to experience the best big compression driver-based setups. Ditto the typical 'high-end' audio speaker of the day from the then esoteric Quad 57 and 63 to Linn Isobaric DMS and PMS, original Vandersteens, early B&W DM7 and robot-looking DM6s etc. I also sold K-Horns, Tannoy Westminsters and the biggest home/pro-oriented JBL monstrosities we could suspend from main listening room ceilings via chains. The business I worked for during almost the entire decade of my twenties was also ultimately on call for many Tampa/Florida area rock and jazz concerts. We assured that the bands' P.A. systems never faltered. I not only got to know many 70s and 80s concert bands, I fell hard for the sheer life thrust forward by very good compression driver speaker systems.

Back at the audio salon I also fell hard for speaker systems with high-quality compression drivers in the critical presence frequencies. They always seemed to present an uncanny sense of being there even when listened to from an adjacent room. 25 years later many of the best speaker systems remain horn types usually with high-quality compression units However, ultimate delicacy and livability in the average home was and remains their Achilles heel. Few of us had/have room for such beasts. Plus, I had succumbed to a pair of speakers so dramatically different in the meantime that many who knew me worried that I had come under the spell of some religious cult demanding that I divest myself of all worldly possessions, especially 300-pound compression driver horn speakers. Instead I had become mesmerized by British mini monitors called the LS3\5a. My then-new 1978 Chartwell version offered much of the sonic excitement of big compression systems with more sonic refinement and a spooky sense of dimensionality I had never experienced. And those vocals? Wow! Of course all that came at the cost of very limited output and dynamic range.

I took in a pair of EL34 p/p 25wpc Leak TL-25 Plus amplifiers on trade, added a new Conrad Johnson PV-5 preamp and a Linn Sondek LP12/Ittok/Asak front end and never saw the need to upgrade for more than a decade. These little extremely volume-limited LS3/5a boxes simply evoked a sense of emotional connection with the music that was not easily surpassed regardless of size or cost.

That’s when my venture off the usual hifi path really began. No more SX-1250 Pioneer receivers with JBL L-100s or Epicure 400+ speakers, no more big compression horns. I made a compilation tape on my Nakamichi 680 to try and seduce my wife of now thirty years over that system. And I should mention that my love for tube-based electronics actually began way back in 1963 when my father (a now long retired Coast Guard's man) returned from the Far East with a Sansui 1000 receiver.

Enough memory lane. Why are we here? After my love affair with the LS3/5a ran its natural course, I moved through a number of more expensive and recognized state-of-the-art speaker systems, some constructed from many dozens of CNC-sliced slabs of either exotic wood or MDF stacked and glued atop one another to form a speaker cabinet, others utilized proprietary resins of some sort to build a finished speaker box said to be totally inert even from cement/resin mixes. Then there were those which applied cabinets using special types and thicknesses of very particular types of tone woods with thin walls designed to resonate in concert with the music or to reduce the usual speaker box’s retention of the musical energy - the quicker release of energy is better philosophy.

Lowther DX-4 and Fostex FE206 ES-R.

Lowther PM6a and Audio Nirvana.

I got inspired by this greater attention to box designs and had an elaborate pair of back-horn cabinets built to house a pair of Lowthers. I liked the concept of no power-sucking crossovers (remember my LS3/5a) that would allow me to give those new/old-fangled single-ended micro power amplifiers a try. Regardless of my many years of speaker progressions, there was always some sort of a box involved - except for the occasional fling with electrostatics (my favorite being the original Martin Logan CLS-1) that offered a narrow band of pure sonic bliss but were far too limited in frequency extremes and dynamics for where I was headed. I think there are now more Quad 57s on AudiogoN and eBay than ever were for sale at any given time when new.

Lowther PM2MkII and Fostex FE206 ES-R.

So how did I go from elaborate box-type speaker systems to becoming an ardent advocate of no box at all? Purely by accident. Remember that my latest box-type speakers are beautiful Baltic Birch Medallion III back horns with all internal turns fitted with bent Birch play for no 90° bends or any sharp angles. These were fitted with a pair of 8-ohm high ferric Lowther DX-4. This was absolutely the best sound I had ever lived with in my home and very full, open, dynamic and lively. Effortless. 2006 was a wonderful year in my audio room indeed.

That same year Mr. Jon VerHalen of Lowther America thought I might have fun trying a pair of Lowther PM2MKII in my Medallion III cabs. Very similar to the PM5a, the PM2MKII sports the same size and mass magnet structure of the famous Lowther PM4a but runs a softer and magnetically not quite as powerful pole piece and back plate. Hence the PM4a has a total flux density of 2.4 while the PM2MKII is 2.2 - identical to my Lowther DX-4. Keep in mind that the Medallion III enclosure was designed for the Lowther DX series with its comparatively tiny Neodymium motors. I constructed a pair of adaptors/risers to fit the PM2MKII’s huge magnet into the Medallion. It sounded like shit! No need to get detailed, the sound was that bad.

Medallions with DX4 and Fostex super tweeters (not needed).

Jon VerHalen about a year ago with the current PM2MkII/Tone Tubby combo.

I was preparing to pack these Lowther behemoths into the wooden crates from whence they’d arrived to return to Lowther America. It just so happened that the previous day I had found the JE Labs website which described a very simple open baffle that their gent had fitted with the Altec 755a. Hey, I had some perfectly sized MDF planks and more than several pairs of vintage eight-inch widebanders along with several Fostex, Lowther DX-3 and DX-4. Within two hours I had a pair of JE Labs open baffles. My plan was to allow my two ten-inch plate-amp powered horn and corner-loaded subwoofers to handle any bass below 100Hz. Surprisingly, I was not particularly impressed with either the Lowther DX-3 or DX-4 in the JE Labs OB. Yes they sounded good but there wasn’t the wholesale sonic transformation several open baffle advocates described. With nothing to lose and just for the hell of it, I finally stuck the big PM2MKIIs on these baffles. Wow! It was as if someone had blown the back of my 13’ wide by 20’ long by 8½’ high listening room into my neighbor’s yard. So much space, air, detail and a sense of palpable dimensional realism I had never previously experienced. Plus there was dramatic weight and power surrounding each musical note. Layered dynamics along with intact tonality offered that same you are there realism even from outside the listening room which I had previously associated with big compression speaker systems - but now with more emotion.

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