PMC Twenty.21 - Walnut

Specifications:
Crossover Frequency: 1.8kHz
Dimensions: H 12.8” × W 6.0” × D 11.0” (+6mm grille)
Drive Units: LF PMC twenty series, lightweight doped 5.5”/140mm cone with cast alloy chassis, HF PMC/SEAS®, 27mm twenty series, SONOLEX™ soft dome, Ferrofluid cooled
Effective ATL™ Length: 1.72m / 5.6ft
Frequency Response: 50Hz – 25kHz
Impedance: 8Ohm
Input Connectors: 2 pairs 4mm sockets (Bi-amp or Bi-wire)
Sensitivity: 87dB 1w 1m
Weight: 11 lbs

Technically speaking

PMC’s unique (Advanced Transmission Line) enclosures have taken loudspeaker design to the highest level, using sophisticated cabinet construction, proprietary drive units, and patented absorption materials and techniques. The benefits are enormous compared to the relatively simple sealed and ported designs currently available elsewhere.

PMC’s innovative approach places the bass driver near one end of a long tunnel (the Advanced Transmission Line). This tunnel is heavily damped with acoustic material specified carefully to absorb the upper bass and higher frequencies radiating from the rear of the bass driver. The lowest frequencies are allowed to pass down the line and emerge from the large vent in the same polarity as the driver’s frontal radiation, the vent acting essentially as a second bass driver.

An important benefit of the approach is that the air pressure inside the cabinet, loading the bass driver, is maintained. This helps to control the driver over a wide frequency range and significantly reduces LF distortion. Consequently, the upper bass and midrange detail is not masked by harmonic distortion and the result is PMC’s characteristically transparent midrange, fast, attacking bass and outstanding clarity.

A further advantage is greater bass extension and loudness than a ported or sealed design of a similar size, even if similar drivers were used. Moreover, the very consistent bass driver loading brings the welcome benefit that the frequency response remains consistent regardless of listening level, and analytical auditioning can be conducted without the need for high replay volumes to achieve optimal bass response – a unique and very valuable characteristic.

‘No other bass loading technology provides such resolution and tonal accuracy at all volume levels’

Click here to read the PMC Twenty.21 Brochure: Twenty.21 Brochure

Reviews:
"The twenty.21s are a visual and tactile delight. ...The cymbals were so crisp, vivid and utterly delightful. No matter what I chose to feed the PMCs, they absolutely lapped it up, giving everything a highly infectious sense of tautness and musically. So the baby of the bunch punches just as hard as the daddy of the range and with width and even more enthusiasm. The PMC twenty.21s are an object lesson in how to wring a big sound from a small box with virtually none of the compromises this usually entails."

"If your heart wants big loudspeakers but your head says the must be small, then look no further."

"The 21s are gifted and accomplished musical performers."
- Adam Smith, Hi-Fi World, July 30, 2012

"Even at (quiet) very low levels the twenty.21 filled the room with music. Incisive, direct and with an open soundstage they even revealed the character of my tube amplifier. I missed nothing, I do not need to add any more superlatives. It seems that I discovered the benefits of an excellent (quiet) speaker."
- Image HiFi, Germany, May 1, 2012

“Wow! The twenty.21’s easy driveability and manageable size add real-world appeal to the purely audiophilic benefits of sublime sound, rich, rewarding bass and terrific imaging. With this in mind, I’m keeping a pair as my reference. Underneath it, duck Dunn’s fast-plucked bass, to the right a sassy horn section, Steve Cropper’s guitar dead ahead, voices far left. It coalesced into a well of soul goodness: no overhang, just snappy attack, while the lower registers were tight enough to rattle my memory bank."
- Ken Kessler, Hi-Fi News, April 1, 2012

"The twenty.21s are fast, involving, dynamic, and produce more bass of much better quality than speakers just 32.5cm tall have any right to claim. They're sprightly, beautifully weighted and sweet, while also being highly revealing. ...These are superb little speakers, and recommended without reservation."
- Tony Williams, Gramophone, January 3, 2012