For sale is a set of crossovers from a set of studio monitors I picked up from a recording studio in Knoxville, TN over 12 years ago. The speakers were upgraded to 3-way (4333A) and I had new crossovers custom built and installed by a local repair shop so these are what came out during that work. I am not a technician, I am an audiophile, so please no tech questions. The guys in that shop thought I could sell these - so here we are.


The JBL 3131A is a vintage 2-way speaker frequency dividing network (crossover) from the JBL Professional Series, manufactured around 1981–1983. [1, 2]
Key Specifications
  • Type: 2-way dividing network (crossover) [1, 2]
  • Crossover Frequency: 800 Hz [1, 2]
  • Allowable Input: 150W (continuous program) [1]
  • Impedance: 8 Ω for low frequency / 16 Ω for high frequency [1, 2]
  • High-Frequency Attenuation: Variable volume control included [1, 2]
  • Weight: ~4.3 kg (per pair) [1]
  • Original Application: Originally packaged and designed for use with vintage JBL monitor speakers like the JBL 4331. [1, 2]
  • Compatibility: The 800 Hz crossover point and split impedance make it functional for custom builds or pairing with 15-inch low-frequency drivers and compression drivers. [1, 2]