Requirements for loudspeaker crossover networks

After defining terms to be used, the need for a crossover filter in a loudspeaker is explained. Justification of crossover filter functions is based on a listening test first proposed in 1962. The requirements for a crossover filter are: 1. partitioning the audio spectrum, 2. a tolerance on power response, 3. control of intermodulation distortion, 4. a tolerance on phasor magnitude response, 5. a tolerance on system group delay, and 6. a tolerance on adjacent channel group delay difference. The audio fad known as time alignment and several crossover networks will be debunked.