The search returned 4 articles:

  1. September 2017: Project: Fully adjustable, 3-way active loudspeaker crossover Pt.1 by John Clarke, PCBs: SC 01108171/2/3 [print issue] [online issue]
  2. September 2017: Project: Fully adjustable, 3-way active loudspeaker crossover Pt.1 by John Clarke, PCBs: SC 01108171/2/3, 8 shop items [print issue] [online issue]
  3. October 2017: Project: 3-way Active Crossover for speakers, Part 2 by John Clarke, PCBs: SC 01108171 [print issue] [online issue]
  4. October 2017: Project: 3-way Active Crossover for speakers, Part 2 by John Clarke, PCBs: SC 01108171, 8 shop items [print issue] [online issue]