PlusSound Allegro UIEM

Cayin Audio's N8ii and HiBy Music's RS8 are naturally worthy of feeding Allegro. But part of PlusSound's brilliance here was designing a crossover that operates at a virtually flat 10ohm impedance and electrical phase, while granting their first flagship 112dB/mW of sensitivity. 

Allegro will always be a powerhouse that scales based on source quality, but as a fairly benign load all listeners will enjoy excellent sound from more humble DAC/amps and music players. 

Indeed, said crossover is the platform to perform for Allegro's drivers. PlusSound's low-order network feeds both dynamic driver bass and electrostatic treble sections. Their slow frequency roll-off slopes ensure accurate phase reproduction and maximum cohesion in their assigned audible band.

And these simpler, lower-order signal paths utilise fewer components such that the crossover saps as little power as possible, ensuring maximum transparency, dynamics and detail reach the bass and treble units.

Allegro's dual dynamic drivers, operating in push-pull isobaric fashion, are more than capable of keeping up with the extended range they operate in.

Both stiff yet well-damped as they rise higher in frequency, these large 10mm drivers are mounted in a 3D-printed acoustic enclosure with a massive rear vent. That aids decompression out of phase, lowering air resistance within their chamber for greater excursion and better drive.

PlusSound similarly mounted Allegro's electrostat tweeters where they would have maximum effectiveness. Placed coaxially against the IEM spout for the best directivity, their wide-frequency bandwidth extends up into the ether.

Their low-order crossover sees these Sonion electrets enjoy the best sensitivity and power-to-SPL conversion, for audibly excellent dynamic ability. In between are six mid-range balanced armature drivers, this time working under high-order slopes to keep them in their ideal range of reproduction to avoid unduly taxing them.

All 12 drivers are masterfully placed in Allegro's shell for maximum frequency and time-domain performance connected by Copper XS, an in-house designed cryogenically-treated Type 6 UP-OCC wire with proprietary insulation.

PlusSound's attention to detail extended to their accessorisation, with custom-designed silicone eartips for ideal acoustics beyond the shell showcasing the technical potential of Allegro.

And PlusSound's flagship Exo Copper+/Hybrid+ cables are included for the perfect signal path to source, placing their secondary twisted litz wire bundle used as the core and unique silver shielding to reduce EMI for listening not plagued by interference. 

Allegro packs quality inside and out. Its polished, anodised, cryogenically-treated aluminum faceplate, body and nozzle carved from seven-axis CNC, and rhodium-plated tellurium copper 2-pin connectors, guarantee PlusSound's flagship will be as life-proof as its sound is timeless.

Proudly carry Allegro in PlusSound's leather storage case cum IEM display stand whether you listen on the go or at home. Such is her performance that you'll never want it to leave your side.

Because if you were surprised by PlusSound's entry into the high-end IEM arena, then that shock extends to the IEM clinic they just put on after over two years of research & development.

While you're enjoying Allegro, explore how you can cable up your other transducers with PlusSound here, or view our other favourite IEMs here.