Here are expanded details of the 4343- 4344 Project Upgrade External Hi End Crossover Network.
The original theme was a high quality passive crossover for use with the JBL 4344 components.
What evolved from our objectives during the design phase was a crossover network that would be external to the 4344 enclosure, bypass all existing passive crossovers and L Pads and wiring, and use the original equivalent 3145 crossover schematic designed by Giskard.
The practical realisation of the design is a pair aluminium cabinets that house the passive filters and a system of terminations and wiring that allow routing of both low and high pass biamped speaker signals via a customised cable to the 4344 enclosure. This approach will ensure the passive filters are isolated from internal enclosure vibrations while also providing phase continuity of the four individual signals from the crossover filters direct to the 4344 drivers.
The enclosures are 9.5 kg each, made from 3 mm aluminium and milled 25mm square aluminium stock. Auricaps and Mills resisters are used in all signal path locations. Pure copper terminations and Welbourne Teflon cable is used throughout. The binding posts are premium grade by Cardas and the 8 pole connector is a heavy duty Speakon. Provision is made for fixed resister values to replace the L pads once the system has been installed and calibrated.
A customised front panel was arranged to allow precise adjustment of the L pads during set-up and installation.
It looks deceptively simple, however there is a lot of fine detail and a reasonable degree of difficulty in the implementation.
In a week or two we will show more details of the installation and set-up.
Ian
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