|
Speakers from the sewer
By Esben Beck
02 Mar 1997
Crossovers
Phew... that's enough about concrete, glue and wood. What about the crossovers, phase linearity, frequency response and sensitivity ? And where are the units' waterfall plots, the on- and off axis response diagrams and the-impedance-magnitude-and-phase-versus-frequency diagrams??
Well, since there is nothing revolutionary about the driver configurations, I will not bother to write a long lecture about this. I think that some short descriptions will be content.
The crossovers were originally made to attain a three-way system, using a capacitor in series with the Seas G17RE-P. I soon discovered that some energy was missing in the upper bass area. I decided to remove the series capacitor, increasing the bass output from the Seas 6.5". Since the 6,5" has a closed cabinet, it will have a rolloff at 12 dB/octave. The crossover to the 8545 is electrically a 6 dB filter with just a single series inductor, but the coupled cavity-system forms a 12 dB lowpass response. Luckily, this matched the 12 dB highpass rolloff for the Seas, and they summed into a quite flat response that worked surprisingly well. This is what my current 6/12/18 dB crossovers with the RLC-circuit for the G17RE-P looks like Fig. 16. The crossover network. As you can see, there is nothing special about it, so feel free to try your own crossover designs. The sensitivity of the speakers is about 88dB.
|
|
Top
