I have to admit that Boston-based Sonner Audio was unfamiliar to me until I read colleague Andy Quint’s 2018 AXPONA report. He was impressed with the potential he heard under arduous show conditions (“Satisfying orchestral weight and timbral nuance were evident even on a brief audition”). Such audio qualities have always been near and dear to my heart, so I was eager to have a listen to this new kid on the block.
Sonner Audio is led by president Gunny Surya—a music and audio enthusiast with a background in industrial engineering, a Master’s in business, and 20 years of experience in technology and industrial companies. Mr. Surya stated: “We apply world-class operation/business practices to Sonner’s operations, such as using state-of-the-art software and tools for speaker design, measurements, QC, CAD/CAM for cabinet design, and CNC machines for cabinet fabrication. We work with well-established companies around the globe to supply our crossover components, speaker drivers, and cabinet material.” Currently Sonner Audio offers two product lines—the two-model Allegro Reference series and the lower-cost three-model Legato Series, with the Legato Series featuring trickle-down technology from the Allegro Reference.
Visually the $8500-per-pair Legato Duo is easy on the eye with soft curves, a slanted baffle, and a rounded-back enclosure. Carefully offset and affixed to its platform base, the speaker is remarkably stable given its sloping angle. This is a two-and-a-half-way, bass-reflex floorstanding design with a driver complement that includes a 1" ring-radiator tweeter, a 5.5" coated-paper-cone mid/woofer, and a 6" custom-designed aluminum woofer. A pair of ports are positioned at the rear of the speaker. The crossover frequencies have been set at 200Hz and 2.5kHz. The svelte cabinet doesn’t employ traditional box-enclosure back and side panels; rather, the enclosure is pressed into shape and then machined into its final form via three- and five-axis CNC into a single curvilinear monocoque designed to reduce internal standing waves and minimize energy storage.
The Legato Duo is acoustically time-aligned as suggested by the raked front baffle—a look reminiscent of slanted-baffle designs like those from Thiel and Vandersteen. Sonner’s design philosophy is to maintain flat frequency response and minimize impedance variations to make its speakers easy loads for amplifiers to drive. Internally, only point-to-point wiring is used (no circuit boards) and components are carefully laid out to minimize electromagnetic interference.
High-quality components and tight tolerances optimize the integration of speaker drivers via Sonner’s “Panoramic Crossover” topology. Sonner maintains that all machining, assembly, and finishing is done with U.S. craftsmanship to assure a reliable and consistent product. Handsome, single-wire, copper-alloy binding posts add a stylish touch. In a clever nod to both aesthetics and function, the baffle’s leather panel is part of the time-alignment design, and it can be covered with a magnetically attached grille.
For this review I powered the Legato Duo with the MBL C51 180Wpc integrated amp with great results. Wire, both speaker and interconnect, was courtesy of Tara Labs (review forthcoming), with Audience Au24SX power cords and an Isotek power conditioner (review forthcoming). I found the Legato Duo easy to drive, but it benefitted from the added control that the MBL afforded from the lower mids on down.
In sonics, the Legato Duo played it straight down the middle with an invitingly warmish signature that seemed to make music more listenable rather than challenging to the ear with excesses at the extremes. The mids demonstrated a presence range of good articulation without veering into forwardness. In transient behavior, the Legato Duo seemed fast in the same way some of the fine designs from Audio Physic speakers have been. Crash cymbal, high-hats, snare-drum transients, and flat-picked instruments really sprang forth with a sparkle that conjured the real thing. And solo violin had a nice balance of aggressive bowing and attack without sacrificing the critical resonant sweetness of the body of the instrument.
The Legato Duo did not overreach in the upper octaves, thereby avoiding peakiness and sibilance; it did not puff itself up in the bottom octaves, either. Treble response was smooth, not quite as bloom-filled and airy as some tweeters but highly listenable. Inter-driver integration and coherence were also good with little sense of tweeter-on-top/woofer-on-bottom discontinuities.