K231 Stereo 3-Way Active Crossover

A Major Upgrade That I Should Have Made Years Ago

I've enjoyed a two-channel, six-amped system for many years, daisy-chaining a powered sub with mid and high monoblocks on both the left and right sides. This set-up made me a believer in the idea of one amp per driver, bypassing loudspeaker crossovers. From time to time, I've wondered if a crossover would offer any improvement, but never saw a product priced comfortably for a long-term experiment. I discovered the K231 early in 2025, and I was thrilled with the improvement in my system from the moment I installed it. In the months since, I’ve never had a regret while listening to a system that now sounds new to me. While clarity and timing improved across the spectrum, the resolution in mid-bass, especially, was startling. I now hear distinct instruments in that range that were previously hidden or murky. A fellow enthusiast and frequent visitor stopped by recently while my system was in full flight. He entered the room and asked with a smile, “What have you done differently?” The K231 is thoughtfully designed, well-built, widely variable (yet easy to understand), noise-free, and good-looking. And I love the idea of swapping XO Modules for a few dollars each, even though I found my original choice was the best match for my components. Yours is the only product for which I have dedicated the time to write a review of this nature and length. Thanks for a terrific game change in my listening life.

Amazing clarity of sound, build quality and ease-of-use

I am using this as two-way crossover between my RCF TT 515-A main speakers and my Bose SUB2. I am using the combination in both live settings and teaching/ practicing/ rehearsal settings. I know most people use this in hi-fi home audio as well as production settings but the unit is certainly robust enough to be used on the road. I love the simplicity and ease of controls. I was able to speak to Mark about the product and crossover settings before purchasing, which was very helpful. My TT 515's sound much clearer, and I am able to cross the frequencies at the right spot (for me 110Hz) with a fairly seamless transition from subs to mains, with great clarity. I may use it with a higher sound quality subwoofer in the future, but it is making my current system much more accurate sonically, and easier to dial-in with the controls on the front (and the dip switches inside).

Perfect active crossover