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When my wife needed unexpected heart surgery in Germany, it naturally shut down my review activities for about 6 weeks. A Swiss friend meanwhile spotted an opportunity. He would purchase the pending review pair as a birthday gift for a British friend of his while a new review pair would be scheduled for delayed delivery to Cyprus. Jacob George agreed to this reshuffle and, on his way back to India from the NYC show, stopped over in Blighty to personally install the first pair. The system would include a brand-new Audio Note Kegon integrated and matching head amp as well as a used Zanden digital front-end and SME turntable (my Swiss friend has exceptional taste and an enviable inventory of audio kit). All this was meant to surprise a highly cultured gentleman who possesses the finest of everything yet apparently nothing even remotely equivalent in the realm of advanced hifi. My Swiss friend was determined to rectify this sadly quite common imbalance and practice the spreading of the gospel in high style for this special occasion.
A day prior to his departure for England, Jacob wrote in: "Delivered the first new pair of Saadhanas to Painted Sky Audio. He's thrilled to bits with it. Says it sounds better than the last three pairs of speakers he's had in his room. He seems convinced the Saadhana is quite the deal." While impossible that the Saadhanas could beat the dealer's earlier mid 5-figure statement speakers in bass reach and slam, ultimate treble extension, ultimate SPLs and such, there's far more to music than subterranean bass, ultrasonics and extreme loudness, all of which becomes relative and equalized anyhow by smaller spaces. It's the old saw about getting
enough speaker for the room, not too much - and what constitutes what can be surprising at times.


"Got back to India yesterday after a very interesting four days in the UK, with the installation certainly being the high point. It was a huge room, about 25' x 45' with a 30' high wooden cathedral ceiling. I was quaking in my shoes when I first walked in. My heart really sank. I have never done an installation in a room even half that size before. But surprisingly -- although far from perfect -- it worked out and the speakers were sounding tonally rather good at the end. They were positioned bang up against the wall so things like soundstaging and such were non-existent - but there was no way I could tell the good lord of the mansion that he had to change the furniture in his 500-year old room around. But I think they liked it and your friend too who ordered a pair for himself. I actually believe we could get close to ideal sound in a room that size if we were allowed to position our speakers correctly. Bass was surprisingly good and as our host commented, actually tactile in the floor. If well set up and in a good room, the bass should satisfy most people. One of the things the Scottsdale dealer told me was that he was getting bass levels equivalent to his big towers. No, the Saadhanas don't dig down to 25Hz but what there is down to about 30Hz is pretty solid and powerful. I think that gives the impression of 'ample bass'."
A publicized exchange between Jacob and a listener asked why Jacob preferred the Lowther driver over the Supravox the Swiss Rethm importer had routinely optioned for his earlier models. Jacob stated simply that designers of wideband drivers had to opt for either bass or treble extension but couldn't have both. Supravox had done the former, Lowther the latter. For the resolution and spark of life Jacob insists on, the Lowther's treble reach and speed were mandatory. Hence he has always chosen to sacrifice bass fundamentals rather than upper harmonics and reflexes. The Saadhana wants to do it all: retain the blazing speed and lit-up ultra
informative behavior of earlier Rethms, then add body and weight well beyond the unassisted Lowthers. As the above insert demonstrates, Tommy Hørning felt compelled to strap two pairs of isobarically piggy-backed 8-inch woofers to his DX45 in the Aristoteles Ultimate model. That's four woofers per side. His Eufrodite uses eight. And it's not just bass extension. It's speed and efficiency to keep system sensitivity on the Lowther level. Paralleling woofers helps to drive that up. It also minimizes excursion requirements to improve articulation. To get away with just two woofers while keeping his enclosure smaller and cosmetically fully finished, Jacob had to go to Peerless to fabricate special custom drive units to his specs. With Lowthers, there's no free lunch.


On to brass tacks. There's a curved hatch right above the Saadhana's metal bands. It's the access chamber for the bass system controls. They select the woofers' low-pass from between 50 - 150Hz; relative bass level with a continuous pot; and a ground lift toggle in case of system hum interactions. Further concessions to real life appear in the custom loudspeaker terminals. That is, over the previous Delrin units: "With the present terminal location and given the state of current audiophile cables (huge and stiff, call me a skeptic), my Delrins were too delicate to hold down garden hoses. However, I am not using one of the high-tech chunky Cardas/WBT-type metal variants either, just simple ones with minimal metal encased in plastic bodies because I don't want that hunk of metal at the termination point. The actual connections are still maintained the same old way, by direct contact between the internal wiring and the spades of the cables, avoiding solder connections altogether." On the sales floor, this is called overcoming objections before they're raised. Jacob has systematically addressed typical audiophile concerns while having his cake. That's a delicate tango of course but vital if you're an uncompromising designer with a clear personal vision and intent on commercial acceptance.


This theme continues with the internal amps. Those aren't your usual off-the-rack subwoofer plate jobs with 4th-order low-pass and class D switch mode topologies. They are conservatively rated 75-watt class AB monos with complementary FET pair outputs designed to sound excellent full-range even though their actual coverage range is restricted by the 4-stage passive variable low pass filter. Input sensitivity is 3V and an ultra-high speed loudspeaker protection circuit is built in. 25,000 microfarads of capacitance and a hefty EI custom power transformer round out the amp specs. While the original concept called for external amps which certain ambitious end users could have bypassed with their own, integration and insistence won out. The integration part we've already covered. Insistence is Jacob's firm belief that for his application, there is no better amp than his own, cost no object. The voicing of the amp is custom-tailored to these very drivers in their exact isobarically horn-loaded alignment. Jacob clarified the importance of this point in a subsequent e-mail:
The two saws with their welded steel jigs are dedicated to cutting, slicing and mitering the back-horn pipes.

"Certain advanced audiophiles of course will assume that they could do better with whatever ultra-expensive muscle amp they favor. I beg to differ, respectfully. Firstly, we do not need a huge amount of muscle as at 96dB sensitivity, our 75 watts into 8 ohms amps (more than 100 into the paralleled 4-ohm load actually driven) are plenty powerful enough. Secondly, our bass system is unique in itself and carefully matched to a uniquely modified Lowther. This requires a custom amplifier/crossover solution to not come apart at the seams. The Saadhana was conceived and executed as an integral loudspeaker system to prevent inferior haphazard results. We've worked very hard to present you with a turnkey solution not because of convenience but because this is what sounds best. The only concern for the owner is to provide a superior amplifier for the Lowther. From our perspective, that is the ideal scenario especially for lovers of micro and mid-power tube amps. Integrating commercially available subwoofers into a Lowther-based loudspeaker system simply does not work. There is no subwoofer out there designed specifically for this task. Ours was and the result is a totally transparent, seamless integration of the bass frequencies into the whole." Then Jacob shared the following:
"I received an inquiry for a passive Saadhana from a distributor who loves the sound but believes that his customers prefer to use their own amps and won't accept our new semi-active concept. Of course I would love the business but I really can't bring myself to go back to the fully passive approach. Like REL subs, our bass amps are designed to take a speaker level input, not a line-level feed. Because our bass system produces music into the low 100s unlike traditional subwoofers which ideally kick in below 40Hz, our amp has been designed accordingly. Coming off a preamp output into it would alter certain parameters.

"Obviously, we'd also have to design a filter and build it into the bass array if we returned to passive yet how am I going to design a network that will match perfectly with the output characteristics of any amplifier a customer may decide to use as bass amp? That's really the crux of the matter. Our filter was designed to match and work perfectly with both the driver and bass amp characteristics. And I did not want to go the electronic crossover route. We really labored hard to design a passive filter with the bare minimum of parts to drive down losses and phase shift. I can't claim zero phase shift but we're down to about 15 degrees which, in my book, is very acceptable and virtually unnoticeable.
"We went through seven different iterations to get our bass amplifier just right until it properly damped the woofers without over damping them. How many customers will have the luxury of auditioning seven different amps in their home before settling on the right one (if they find one that works at all)? Our amp is very well made but a fraction of the cost of a comparable outboard amp because we avoid the chassis and additional hardware which is where most the money goes with regular amplifiers. Plus, an outboard amp would have to come with its own volume control and most simply don't." As in life, audiophile habits are rooted deeply. They're most reluctant to be eradicated by change. Regardless, lovers of triode amps in particular should already know well from personal experience that for all their vocal and treble band glories, such amps are compromised in the bass. Trying to match them to highly damped active subwoofers without causing audible discontinuities of textures and transients is a fool's errand. That's precisely the issue the Saadhana addresses in one fell swoop. In turn, it asks for nothing more but a single pair of speaker cables and two power cords. As a diehard triode hound myself, it's simply foolhardy to argue with the logic and wisdom of this approach (and Zu Audio would concur as both their Definition and new Presence models pursue a similarly semi
active concept). Incidentally, if you believe in the old adage that a man's environment reveals much about his character, you might enjoy a virtual visit to Jacob's residence which he designed and built himself through his firm Design Combine.

While awaiting delivery, another company's principal contacted me about his newest DX55-fitted monitor speaker for possible review. When I mentioned that I'd heard stock DX55s run full-range in small cabinets and unassisted to know them as bright and bass shy (a double whammy) and asked how he had modified the driver, I was promptly lectured - on the sanctity of the driver as though Lowther's age equated perfection; and thus the foolishness of modifying the DX55. Vis-à-vis personal experience, I failed basics. No matter how clever you get behind the cone with tuned chambers and such, the whizzer is upfront. How can you notch-filter its hot spots mechanically or acoustically by dealing with the rear wave exclusively? As Harry said to Sally on another throbbing topic: "You can't take it back. It's already out there". Rethm ships its drivers uninstalled (their far smaller and lighter shipping carton makes them less prone to transit mishappery) so I had natural cause to inspect their signature Rethm skirt closely.

The Lowther is a freakish device. It mates a max voice coil travel of +/1mm -- tweeter territory to press the point -- with a flux density of 20,000 gauss or 2 Tesla and a 1mm air gap. As Steve Deckert of Decware discovered when listening to a friend's DX3 in a bass reflex enclosure, "my Select Zen Triode SE84C-S amp ended up being almost twice as fast as I thought it was, leaving me somewhat stunned." Inspired, he ordered a pair of DX55s for personal experiments. "The drivers were packed well but the inside cone was less than round (like many other Lowthers that I've observed) and that burst the bubble of hope that somehow mine would be perfect. The phase plugs were not centered on the pole piece and are a rather inexpensive plastic. The casting marks on the frame were all too evident and the general fit and finish suggests these are hand-made drivers (which they probably are). All of this scrutiny was brought on by the simple event that they somehow feel these drivers should cost $700/pr. Having a speaker repair business for 10 years now, my first impression was that I could have done a better job myself. At best I can only see justification for a price tag of around half this amount." After installing the pair in his personal horn enclosures without any optimization and noticing significant flaws, Deckert was nonetheless smitten with "attack and acceleration from the DX55 that was more impressive than the best and biggest electrostats. It was more dynamic on drums than high-quality PA speakers on very large amps. It was better than a 500-watt cost-no-object audiophile system cranked to the wood. This from a pair of 6-inch drivers was a hard pill to swallow - but I heard it happen."
Taunted by transient response and speed, shocked by grossly aberrant frequency response, Deckert was ready to quit when a Zen moment struck: "I decided to try something totally off the wall that would modify the impedance curve and gently coax a more balanced response out of the thing. I wound an air-gapped transformer on a silicon steel core with a low impedance primary and a low DCR with the intent of putting it in series with the driver. I wound a high impedance secondary on the same high quality core and shorted it to dampen the primary. This was rather fascinating because without the secondary shorted, there was little that passed through the circuit, probably a 12dB cut in output across the board. Shorting it coupled the transformer so well that you couldn't hear much if any difference between having the unit in or out of the circuit. I knew I was on to something when I decided to make it variable. I took the 9800-ohm impedance of the secondary and shorted it across a 100K (ten
Deckert's gizmo
times the secondary value) variable potentiometer. I installed the gizmo in such a way that I could A/B the speakers with and without the device and did so many times. The variable pot was the ticket. It allowed for a wide range of control. I found the best setting by starting with it all the way up (which is basically non-detectible) and then slowly backed it down in small increments. I was thrilled that the only things it seemed to attenuate or repair were the things I was trying to get rid of! Everything else seemed untouched or rather I should say, it actually improved quite a bit."
This illustrates the kind of serious modifications required to overcome the DX55's inbuilt flaws. Once Steve Deckert had locked in his particular tweaks, a DX55-fitted speaker became his reference. Interestingly, he offers measurements that, while much improved over the stock driver's behavior, are still far from perfect. It's this precise lack of correlation (he provides graphs) with his flummoxed reaction in the listening seat that make for an enlightening read. Naturally, Jacob wrestled with the same issues. He addressed them in Rethm fashion while adding bass Deckert too called "completely missing".
To understand one of Lowther's transient speed achievements, one turns to their hi-ferric coil control system developed "to overcome the problem of keeping colloidal ferromagnetic fluids within the magnet's air gap throughout the frequency range of our full-range drive units. We realized ferromagnetic fluids offered advantages but except for the higher frequencies, we were unable to keep the fluids in place. Lowther's latest hi-ferric system is based on a compound of ferrous oxides securely encased in a high temperature resistant plastic cocoon which is attached to the voice coil. It remains securely in position throughout the entire frequency range of our full-range drive units and assists in maintaining better temperature control. Sensitivity can fall approaching 1% for every 2º C increase in coil temperature. In addition, unwanted voice coil oscillations are greatly reduced. The improved damping factor allows for a faster transient response. Hi-ferric has another advantage. It is actually an energized magnet system in its own right. As current passes through the voice coil, the ferrous material of the
hi-ferric system is magnetically energized. As like poles repel and unlike poles attract, the hi-ferric system attached to the voice coil is either attracted to or repelled from the host magnet's air gap, depending on the polarity of the applied signal. As the velocity of the voice coil is substantially increased, the transient response time is reduced. Between signals the hi-ferric system is immediately attracted to the central position within the air gap, thus increasing the rate of damping and reducing unwanted coil oscillations to a minimum."
Interesting about Lowther's optional Phase Equaliser which screws in place of their stock stabilizer (and which Jacob replaces with a wooden bull nose) are the conceptual parallels to Rethm's punctured extra skirt. Its hole pattern was arrived at after much experimentation. Sez Lowther about theirs: "The main function of the standard stabilizer is to reduce interference caused by opposite sides of the inner cone cancelling out sound waves at certain frequencies. The function of the full stabilizer, in addition to reducing sound wave cancellations, is to act as a diffuser to guide the sound waves to the walls of a horn fitted to the front of a drive unit. The new phasing equalizer forms a horn contour between itself and the wall of the inner cone. This allows the high frequency response to be much improved. For the same reason the higher midrange
response is also greatly improved. The reproduced sound is cleaner and clearer with much better separation of musical instruments." The very creation of this add-on device admits to issues with the bare driver. If Rethm addresses them with front-of-driver modifications among other things; Decware electronically; and Hørning by neutering and removing the whizzer altogether - why cannot Lowther themselves issue a modernized improved driver that doesn't enforce significant after-market modifications? Quipped Jacob George, "I keep buying Lowthers because for what they do so well, there is no other choice." The upshot of this has parallels everywhere. It could be called leaving the middle. Each time one strives to specialize by exulting one aspect of a group of attributes over all others, there's the risk of imbalance. Eventually, there's pathology. On to the Saadhana proper now.
It's not until you ponder this speaker in the flesh that you appreciate fully the challenges of working numerous compound angles and curves into an organic whole. From a doability perspective, the Saadhana enclosure seems an utter nightmare. But, Rethm really pulled it off.


The only tricky part is docking the two halves while fishing the thin copper leads from the bass module through the slots and onto the posts of Jacob's custom terminal.


With the copper ribbon's punched hole just the size of the post and the available length just sufficient, this is not a procedure you'd want to do a few times a month as reviewers might.


Truth be told, I personally would prefer a somewhat longer and round solid-core conductor to simply wrap around the post - but that's mister change speakers once a week talking.


What Jacob has done is purity incarnate. The copper ribbon connects from the screw-on terminals of the driver directly to the post without a single solder joint. Inspired by the Cardas twin design, one bracket with a central hex bolt rides on two non-metallic posts over which the copper ribbon to the Lowther is permanently installed with a simple hole through it. Lay the equivalent woofer ribbon over it, insert your speaker cable spade atop, clamp down the bar with a hex driver and presto - a very secure, minimal metal connection à la Eichmann philosophy.

Other trick wrinkles over prior Rethm implementations are how the dispersion ring around the Lowther affixes onto the actual driver mounting bolts' stand-off ends with embedded rubber grommets; and how a pre-fitted poly felt ring behind the cone eliminates reflections off the basket and motor front. You'll need a bit of black electrician's tape to mount the snow-cone rear wave guide atop the magnets, a very easy 1-2-3 procedure.


The speakers are mirror-imaged so the speaker/power cable connections can be made inside or outside; and the amplifier control cover comes off easily to tweak settings once the speakers have been positioned and spiked. As you attach the speaker cable, be sure to not reverse the metal bridge that clamps it down. The non-conductive white and black spacers face down onto the spades, not back at you - unless you want your amp to see a dead short. Jacob recommends to set up the front halves first while moving them about freely for best imaging and lower midrange fullness. Once their positioning has been locked in, simply dock the rears, then ramp up the bass level and turnover frequency controls until the bass fills out. And that's all for specs, features and setup she said.