PMC Twenty5 21i Speakers (Pair)

The PMC Twenty5 21i Speakers are the best value model in the Flagship Twenty5 range. i stands for improved and new technologies have made the 21i range sound even better. The PMC Twenty5 21i Speaker is a two-way stand-mounted design with a power handling of 150 watts.

The woofer is a 140mm long throw g-weave design and the tweeter is a 19mm twenty5i series soft dome unit. This is a compact unit but there is nothing small about the sound. This is thanks to PMC’s Advanced Transmission Line system that boosts the bass.

Advanced Transmission Line system

The natural and realistic sound of the PMC Twenty5 21i Speaker is due to the Advanced Transmission Line (ATL) bass-loading system. The energy generated by the bass unit is fed through a lined tunnel in the highly braced cabinet. The tunnel is lined with custom-designed acoustic materials that absorb most frequencies apart from ultra-low bass.

These low frequencies are then fed out through the Laminair port on the front of the cabinet. This gives the effect of a far larger speaker. Moreover, the amount of bass is not dependent on the volume level, giving a balanced sound.

Laminair port

The PMC Twenty5 21i Speaker features the Laminair aerodynamic vent to enhance bass performance. Formula One racing car technology was used to create a vent that reduces turbulence and drag. As a result air noise is removed and the bass has supreme timing and the ultimate in dynamic range

Bass and mid-range drivers

The PMC Twenty5 21i Speakers use PMC-designed drivers. The woofer is a 140mm long-throw g-weave design that has a cast alloy chassis. As a result, the new woofer has an ultra-vivid mid-range clarity. Notably, the cone is made of resin-bonded, fine-weave glass fibre. It was found that fibre-glass is stronger than paper while maintaining an uncoloured sound. Moreover, the magnet and motor system is 80% more powerful than previous versions.

The tweeter

The tweeter in the PMC Twenty5 21i Speaker is based on the excellent tweeter from the twenty series. It is ferrofluid-cooled and 19mm in diameter. Moreover, the surround has a wide dispersion grille. This creates a far larger audio picture.

The crossover

The crossover is an important part of multi-driver speakers and must provide a flat frequency response. It is used to separate the low and high frequencies, which are then fed to the correct driver. The PMC Twenty5 21i Speaker is a two-way unit and the crossover was designed using computer simulations and extensive listening tests.

The crossover is built using a military-grade glass-fibre circuit board. This has the widest and thickest tracks possible to reduce resistance and provide a high current capacity. Each component is carefully chosen for the best sound and performance.

The cabinet

The PMC Twenty5 21i Speaker can be stand or shelf-mounted. They are also good for effects speakers in a home cinema system. The cabinet was designed with the aid of accelerometers to measure panel resonances. Additionally, different isolation materials were tested and the cabinet sizes were tweaked, to optimize the stiffness. Moreover, the stainless steel spikes can be accessed from the top for ease of adjustment.

This combines perfectly with the PMC Twenty5 subwoofer and can also be placed on separate PMC Twenty5 stands for elevation and sound distribution.