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For hi-eff widebanders of ±100dB, there's been a long-standing quasi consensus - triodes are best. As described in its review, Tellurium Q's single-ended Mosfet amp is easiest conceptualized as a pentode circuit with bipolar junction transistors. That's because it sports a keen 3rd rather than 2nd-order harmonic voicing such as we'd get from push/pull circuits. What's more, the Mosfet-typical minor warmth so often deliberately harvested for its overlap with valve virtues has been exorcized as well (an aspect similar to how the Exicons in Bakoon's AMP-11R don't sound like typical Mosfets either but closer to BJTs).

In the FirstWatt catalogue all this made the Iridium 20 a kind of super F5. I'd called the sonics "clear as a bell, sharp as a whistle, penetrating like a search light in the fog. Tellurium Q's Iridium 20 amp is a massive antidote to sonic congestion and indecisiveness. Speakers copasetic with its power rating which perhaps suffer a bit from energy-robbing network filters will get the proverbial kick in the arse. Aficionados of completely lit ultra-specific and well-sorted soundstages will be in love. So should be fans of close-to-stage proximity and heightened beat precision. Here the former doesn't mean a foreshortened perspective or lap dance. It simply means uncut transient energy as one hears it close to a drum kit."


If widebander core appeal is similar lucidity/directness, why wouldn't this amp have been an ideal Saadhanist? Attempting to answer that gets us at the heart of both the breed's appeal and associated requirements to cultivate or manage its virtues. Using a larger whizzer-fitted driver involves progressive beaming or bundling which is specific directionality. Now add to this an even mildly rising presence region response—here key are small and even rather than ragged deviations—then pepper with what might be nonlinear dynamics whose most greased reflexes are likewise centered in the upper midrange.
Because all of it occurs in the window where human hearing is most acute and sensitive, adding extra paprika with amplification that majors on extreme separation and leading-edge bluster gets too sharp and biting. That Rethm's largest driver still exhibits a minor lift was obvious when the speakers were toed in directly. Very small remnants in straight-ahead mode remained detectable on Claude Chalhoub's neo-classicist Diwan with his modal Middle-Eastern solo violin against Rococo string orchestra. In the third octave above middle C, certain notes spiked a tad like tiny refractive glints on rippling water.

Pooling into the same equation is a whizzer's enhanced surface area over a standard 1-inch tweeter. Whilst the latter wins on raw extension and a ribbon goes even higher, the former beats a dome's subjective air movement. Because the Saadhana is a proper widebander which even without active bass is surprisingly satisfying and with it becomes certifiably Stereophile class A-rated fullrange, none of this creates a top-heavy tonal balance. If desired and dialed in accordingly, one can in fact move the tonal center down to sit below neutral. What remains regardless—and this is the widebander's trick and allure—is a lit-up sensation of great speed and dynamics. These dynamics express themselves with unusual brio in the 6th through 8th octaves.


It's why coming off widebanders returning to conventional multi-ways can seem so easily muffled. That extreme intelligibility of nuanced micro expressiveness across our hearing's primary bandwidth dulls. It's easiest to demonstrate this at whisper levels a bare crack above mute. It takes most people a few minutes to step down their aural vision to such minuscule signal. Once they do it's invariably illuminating just how much more one now hears with a light-coned widebander over a conventionally heavier multi-way which gets cardboard opaque. Lesser widebanders simply take undue liberties once they begin to transition into tweeter mode. At very low levels that could translate as pleasant intelligibility still. At standard to high levels, it mixes negative brightness and coarseness into otherwise positive liveliness.


The Saadhana has banished these demons into latent seed form. An amp like Tellurium Q's can still spark them. An amp like the SIT1 nearly completely avoids them. A slower thicker triode amp might well eradicate them altogether. If one starts out with as balanced a speaker as the Saadhana, choice of amplification—Voxativ in fact actively discourages even silver cabling—becomes strategic seed management. If one starts with a lesser example where seeds are actual weeds, even the mellowest and cushiest of amps won't erase them. No constant gardener for them. By preceding my SIT1 amps with Nagra's valve Jazz preamp and AURALiC's sweetly triode/DSD-flavored DAC, I had what I considered an ideal systemic entry into Jacob's sonic aesthetic. Whilst he might still prefer an Ancient Audio caliber SET, the point is that these should be quite subtle shifts. They'll only accommodate personal tastes, not be essential repairs of objective flaws.


Which gets us to specifics vis-à-vis the soundkaos Wave 40. In Wojciech Pacuła's Acuhorn Superleggera Giovane85 review, he described its designer's approach of direct-coupling his basket-less driver to the cabinet as related to how a violin's internal sound post or 'soul' couples its strings to the body. As the next photo shows, one simply wonders why he'd choose thick laminated wood for his corpus. Would a violin made of Plywood still work properly?

The rest of Acuhorn's driver glues atop this assembly. The lip of the pleated fabric surround glues straight on the baffle.
If you've ever asked yourself how a small instrument like a violin can produce such room-filling sound and carrying power across distance, it's because its thin top and bottom actively oscillate to release more energy than the strings alone... er, wood. Damping this augmentation action with Sorbothane sheets would kill the sound. You'd hear the very same notes but with diminished sheen, vigor and crippled carrying power. What the Swiss eggs had over their Indian architectural wonders—two other visitors caressed the Rethms whilst muttering génial and magnifique which even this non-Frenchie got, bien sûr—was this violin/guitar corpus action. The Wave 40 sounded bigger and gushier. To a certain extent this could be offset by playing the Saadhanas louder. Of course that's the cheapest old trick in the book. With matched levels meanwhile, its constantly energy-shedding front/rear baffles of Alpine Spruce tonewood had the Wave 40 exhibit greater in-room projection and fill of scale. The eggs with their crossover'd widebander and dedicated tweeter also were less directional. This meant greater stereophony far off axis.


On bass the Saadhana occupies true subwoofer turf. It obviously owned the battlefield unless the already costlier Wave was joined by a subwoofer to cost €25.000. Then things were evenly divided. Stereo Rethm bass was more specific on localization and textures. Particularly on ambient fare with synth effects, mono bass with strategic 20Hz boost did something extra for space and gravitas. Sonic balance was a draw between two equals of slightly diverging strengths. On fiscal balance the $14.750/pr Saadhana is a complete speaker. At $21.350/pr the Wave 40 is a superlative widebander in search of low bass.
Saadhana and Wave+Submission showed equal resolve sorting out the breed's perennial power-zone issue. Here most widebanders go soft because raw shove seriously lags behind the upper bands' snappy spunky dynamics. By extending widebander reach to a solid ~55Hz, each had the upper-bass textural and directional cues in full stereo whilst enjoying sufficient overlap with active low bass to add raw power. With Rethm's isobaric-in-triplicate woofer loading, finally perfected is not extension (that was previously licked) but punch. Think realistic kick drum. When that exhibits proper snap, everything else on the slammatronic subject locks into place. Because its woofers are invisible and the faceted cheeks disguise true width, bona fide infrasonics seem a lie to the eye. But rest assured that my go-to track "Gold Dust Bacchanalia" from Mychael Danna's Kamasutra soundtrack left no stone unturned vis-à-vis the towering class-D 12-inch Submission.


The latest Rethm Saadhana really is the first high-efficiency widebander of my acquaintance to offer factual-to-20Hz in-room bandwidth in a unified enclosure. Forgot 'good for the breed' qualifiers. Forgot the common rationale—that no woofer could match the speed of a 100dB light-coned paper driver—for why such integration hasn't been attempted more often. The true answer would be laziness, mental constipation based on puritanical beliefs or lack of raw design chops. What was gratifying is that despite being placed essentially where my big twin-ported AudioSolutions Rhapsody 200 would go, the Saadhana exhibited none of the latter's sorry predilection for exciting room boom and causing excessive corner loading to reinforce my dislike of ported bass alignments. They reached just as abysmally low as the Zu subwoofer which was placed strategically in the middle of the front wall yet played as clean and bereft of any obvious room punishment within 1.5m of the corners where many fullrange-ish speakers begin to interfere. What's more, bass had natural elasticity and nuance. With this overview we've now crossed off the most noteworthy basics.