Напольная акустика — PMC twenty5.24i

The twenty5.24i is a two-way passive tower speaker in the twenty5i series of the British maker PMC, the range that replaced the original twenty5 line in 2021. The UK recommended price in May 2021 was GBP 5,495 per pair. Walnut, Oak, White Silk and Diamond Black finishes are listed. PMC also offers an ACTIVE twenty5.24i with integrated amplification, and a twenty5i ACTIVE upgrade is sold for converting passive pairs later.

Key specs that matter

A 170 mm (6.5 inch) long-throw g-weave cone, mounted on a cast alloy chassis, handles the bass and midrange. The treble is covered by a 19 mm SONOMEX fabric soft dome of wide dispersion type, built by SEAS to a PMC design, with ferrofluid cooling. PMC rates the response at 27 Hz to 25 kHz, sensitivity at 89 dB for 1 W at 1 m and nominal impedance at 8 ohm, and recommends amplifiers from 15 W to 200 W. Height is 1015 mm plus 20 mm of spikes, width is 192 mm, or 275 mm across the plinth bars, and depth is 419 mm with 9 mm more for the grille. Each speaker weighs 23 kg.

Engineering and use context

PMC forms the enclosure from precision machined HDF panels, some of them as thick as 40 mm, and it houses the Advanced Transmission Line that loads the bass driver. In this floorstander the effective ATL length rises by 50 percent compared with the twenty5.22i, to 3 m, and the line terminates in a Laminair vent, an aerodynamic opening whose shape PMC links to Formula 1 engineering. The crossover point sits at 1.7 kHz with a 24 dB per octave slope, lower than the 1.8 kHz used in the previous twenty5.24, a choice PMC made to smooth the off-axis response. The cabinet stands on spiked anti-vibration plinth bars intended to limit vibration passing from floor to cabinet and in the opposite direction. Cable connection uses one pair of 4 mm binding posts on the rear panel near the base, so the passive version is wired with one cable per channel.

Pairing

Good efficiency and a benign impedance mean that even modest amplifiers can drive the twenty5.24i, while PMC's power ceiling leaves room for more powerful stereo amplifiers. Within the series the twenty5.sub and the twenty5.ci centre allow a pair of twenty5.24i towers to grow into a surround setup.

Alternatives

The PMC twenty5.26i is the bigger tower of this family, adding a 50 mm chambered soft dome midrange for a three-way layout.