Напольная акустика — Russell K Red 150

The Red 150 is a slim two-and-a-half-way floorstanding loudspeaker from Russell K, the British brand founded by designer Russell Kauffman. It pairs two 6.5 inch bass units with a 25 mm soft dome tweeter in a narrow MDF column, and it later served as the basis for the upgraded Red 150Se, which added a revised tweeter and a metal plinth in place of the MDF plinth used on this version.

Key specs that matter

Russell K lists a frequency range of 20 Hz to 22 kHz, noting that the low end depends on the room, and a sensitivity of 87 dB at 1 W and 1 m. The cabinet stands 950 mm tall, or 1,000 mm with its plinth, base and spikes, and is 240 mm wide and 250 mm deep. Both bass units use impregnated paper cones with high-power ferrite magnets and Faraday copper rings meant to cancel distortion. The crossover rolls the lower woofer off at 80 Hz with a 6 dB per octave slope, so it works as a sub-bass driver, while the bass-mid unit hands over to the tweeter at a nominal 2,200 Hz with a 12 dB per octave slope.

Engineering and use context

Sides, top and back are made of 16 mm MDF and the front baffle of 19 mm MDF. The enclosure carries no damping material. Instead it uses shelves with apertures that act both as braces and as acoustic loading for each driver section. The reflex system is internal and is tuned to 21 Hz, so the tuning frequency sits close to the bottom of the quoted range. The tweeter level is set with a deliberately misaligned Zobel network rather than a conventional resistor pad. Each driver has only one component in its signal path, which keeps the part count of the network very low. The single-component approach and the absence of cabinet damping reflect the same design ideas that Russell Kauffman applies across the smaller Red stand-mount models.

Pairing

With its moderate sensitivity the Red 150 reaches normal listening levels without a very powerful amplifier in a 20 m2 room, though an integrated transistor design with current reserve suits the two paper-cone woofers well. The spikes supplied with the plinth are intended for coupling the speaker to the floor, and the narrow front makes it straightforward to place in smaller living rooms.

Alternatives

The Russell K Red 150Se is the updated floorstander built on this cabinet, with a new tweeter carrying a metal faceplate and a metal plinth.