Полочная акустика — PMC twenty5.21i

The twenty5.21i is the most compact two-way box in the twenty5i series from PMC. The series was unveiled at the Bristol Hi-Fi Show 2020 and reached UK buyers from March 2020, and in July 2025 the prophecy1 arrived as the direct replacement for this model. The UK price was GBP 2,395 per pair. The cabinet has a rhomboid parallelogram shape with a sloped front baffle, so the tweeter and bass driver are set back to different depths for time alignment.

Key specs that matter

A 140 mm long-throw g-weave cone, held in a cast alloy frame, covers the bass. The tweeter is a 19 mm twenty5i series SONOMEX fabric soft dome built by PMC with SEAS, with ferrofluid cooling, fitted with a 34 mm surround and protected by a dispersion grille. The dome is derived from the tweeter of PMC's fact range and was developed to work down to a lower frequency than the one in the earlier twenty5 models, with broader dispersion helped by the new grille waveguide. PMC specifies a response of 46 Hz to 25 kHz, a sensitivity of 86.5 dB for 1 W at 1 m and an impedance of 8 ohm, and PMC suggests amplifiers of 30 W to 150 W. Each speaker is 340 mm high, 162 mm wide and 284 mm deep including terminals, and weighs 6 kg.

Engineering and use context

Drivers meet at 1.7 kHz with slopes of 24 dB per octave, a lower point than before that lets both drivers work in their most linear regions. PMC names high-frequency definition, crossover design and reduced unwanted vibration as the main changes over the previous twenty5 generation. Inside the HDF cabinet the Advanced Transmission Line is folded four times and reaches an effective length of 1.72 m. It ends in a Laminair outlet designed to reduce the efficiency losses caused by turbulence as air leaves the line. Four finishes are listed - Walnut, Diamond Black, Oak and White Silk. An ACTIVE twenty5.21i version also exists, with amplification inside the cabinet, using 100 W RMS for each of the two drivers, an active crossover at 1.65 kHz and balanced XLR plus unbalanced RCA inputs with an input impedance above 14 kOhm, listed at USD 6,599 per pair.

Pairing

The steady nominal load allows a wide choice of stereo amplifiers. PMC sells dedicated stands for the model, each 634 mm high and weighing 19 kg, listed at GBP 400. Owners who later want an active system can use the twenty5i active upgrade instead of replacing the speakers.

Alternatives

The twenty5.22i is a bigger standmount sibling within twenty5i.