Полочная акустика — Klipsch R-51M - BLK/GNM

Klipsch builds the R-51M as a two-way passive stand-mount for its Reference series, built from 2018. The BLK/GNM suffix identifies the black and gunmetal version, and Klipsch supplies them as a pair. Within that generation it ranks above the smaller R-41M bookshelf model, with a larger woofer, a taller cabinet and higher power handling. Klipsch Group is based in Indianapolis.

Key specs that matter

A single 5.25 inch woofer, a spun-copper unit with an injection molded graphite cone, works with a 1 inch aluminium LTS tweeter loaded by a square 90 x 90 degree Tractrix horn. The two meet at 1,660 Hz. Rated frequency response runs from 62 Hz to 21 kHz within 3 dB. Sensitivity is 93 dB for 2.83 V at 1 m. Nominal impedance is 8 ohms, and power handling is 85 W continuous and 340 W peak. The cabinet is 338 mm high, 178 mm wide and 215 mm deep, and one speaker weighs 5 kg. A set of four rubber feet comes with each pair.

Engineering and use context

Linear Travel Suspension is the Klipsch name for a tweeter suspension made of Kapton film, used because the material is both stiff and very light, which keeps moving mass low and efficiency high. The graphite-filled injected cone of the woofer follows the same logic, resisting flex so it breaks up less inside its passband. Klipsch attributes the high sensitivity to the combination of this woofer with the horn-loaded tweeter. The horn also narrows the tweeter's dispersion, concentrating high frequencies toward the listening position instead of spreading them to side walls. The enclosure is reinforced MDF wrapped in scratch-resistant textured wood grain vinyl, and the bass is tuned by a rear-firing reflex port, which calls for some space behind the cabinet. Visible fasteners on the front are part of the styling, and the grille is a slim magnetic cover. Only one pair of gold-plated binding posts is fitted.

Pairing

Being efficient and benign as a load, the R-51M reaches high levels on little power, so small integrated amplifiers and entry AV receivers are workable choices, while the continuous power rating marks the upper limit to observe. Its bass limit suggests adding powered bass support when watching films, and an AV receiver with bass management can hand the lowest octave to that sub, relieving the woofer of deep bass excursion at high volume.

Alternatives

For a step into the Reference Premiere range, the Klipsch RP-500M II offers a Cerametallic woofer of the same size, a titanium tweeter and response to 50 Hz.