diplexer

Crossovers or diplexers are circuits in which filters are used or combined: Highpass, Lowpass, Bandpass and Bandstop. The term crossover is used in RF technology, antenna technology and also in acoustics and always indicates that certain frequency ranges are fed separately to downstream circuits or components.

1. In RF technology and microwave technology, crossovers are found in antenna systems and community anten nas to separate the different frequency ranges for satellite reception, terrestrial broadcasting and the various television frequency bands from each other.
2. In broadband distribution networks, crossovers separate the frequency ranges and the outward and return channels for the various services fed in.
3. In acoustics, crossovers are used to separate the different frequency ranges for the different speakers in a loudspeaker cabinet.
   

   2-way crossover, photo: Lautsprechershop

   With such crossovers, which are called crossovers in the English-language literature, the corresponding frequency ranges for tweeters, midrange drivers and woofers or subwoofers are selected. In addition to the separation of the frequency ranges, crossovers ensure impedance matching and that the individual speakers are not overloaded and thus reproduce a distorted sound image.
   

   Frequency ranges of woofer, midrange and tweeter in a 3-way combination

   The individual frequency ranges of the crossover depend on the one hand on the concept of the loudspeaker cabinet, whether 2-way or 3-way setup, and on the other hand on the frequency response of the tweeter( HT), midrange( MT) and woofer(TT). Thus, in a 3-way system, the woofer could cover the frequency range up to 200 Hz and at this frequency the midrange driver could become active. The slopes used here are usually 6 dB/ octave and 12 dB/octave.