Russell K loudspeakers is the brainchild of Russell Kauffman, a man well known in the UK audio world. Russell has been involved in many of the country’s best-known loudspeaker brands in one capacity or another for more years than any of us would care to remember, although his most recent client was working as the designer for Morel loudspeakers. Perhaps his best-known design there is the Fat Lady design, an intriguing three-way, four-driver flagship tower speaker that looks a little like a, erm, fleshy female.
However, the course of the international design does not run smooth, and with Morel based in Israel and Kauffman based in the Home Counties of England, the relationship gradually came to an end. It was time for Kauffman to carve his own niche, creating a line of loudspeakers that bear (most of) his name. The Red 100 Precision Audio Loudspeaker was the first product from the brand, although a smaller Red 50 bookshelf quickly followed, and yet more models are in development. The design stays in the UK, although manufacture moves to Poland, where quality speaker builders still exist in good number.
This preamble would be unimportant were the Red 100 just another two-way, front ported standmount. Looks can be deceptive however, and the loudspeaker has a lot going on under the skin. Russell Kauffman’s design draws on some elements of the classic BBC research and development that gave us loudspeakers like the LS3/5a. In particular, he agrees with the concept that a thick-walled loudspeaker cabinet adds coloration that can be heard in a thickening of vocals. By using 16mm MDF, except for the 19mm thick front baffle, the Red 100 manages to retain a lot of the benefits of a thin-walled cabinet. However, instead of using bitumen pads for damping, Russell Kauffman just goes for low cabinet flexing, thanks to two braces above and below the woofer. These feature a number of apertures that act as tuned acoustic loading. This makes for an energetic cabinet when music is playing, but one that dissipates energy quickly when it isn’t.
The cabinet is totally undamped, without even a glimpse of BAF wadding, foam, or bitumen-lined walls. If you unscrew the bass driver, you are met with bare MDF walls. The reason for the absence of damping in the Red 100 is that Kauffman suggests its action is never even across the full frequency response and acts to slow down the speed of sound travelling within the cabinet. However, he’s also quick to point out that this doesn’t mean those with damped cabinets (which is probably about 90% or more of loudspeaker users) should experiment with removing that damping; a designer engineers a cabinet anticipating the acoustic load that comes with the damping used, and changing that damping messes up those loading calculations, and messes up the sound of the loudspeaker in the process.