Vivid Audio Filter Networks

For a set of drivers to blend together seamlessly into a whole it is essential that their individual acoustic responses adhere accurately to certain defined filter shapes. We have chosen fourth order Linkwitz-Riley filters because of their ideal phase and summation characters through each crossover point which also yield symmetrical dispersion patterns.

All the crossovers in our loudspeakers are designed and built in-house to give the best results.

For a set of drivers to blend together seamlessly into a whole it is essential that their individual acoustic responses adhere accurately to certain defined filter shapes. We have chosen fourth order Linkwitz-Riley filters because of their ideal phase and summation characters through each crossover point which also yield symmetrical dispersion patterns.

Vivid Audio Filter Networks

Thanks to the intrinsically smooth response of the drivers in their respective enclosures, the business of crossover design is made relatively straightforward but when combined with the use of computer aided analysis it has become possible to create complete sub-system responses which are astonishingly faithful to the ideal function; levels of accuracy which were once thought only possible with active systems.

In the set of curves illustrated to the right, the response of the raw driver is shown together with a target response for the driver with filter. The result of adding a passive filter designed for a purely resistive load is quite far off the optimum showing a low output and peaky response. Running the circuit through computer optimiser dramatically improves the match to the target. The process is repeated for a second driver again resulting in a close match to the target response. When the two drivers and filters are run together the result is a near ideal summation.

In common with both drivers and enclosures, all our crossovers are built in-house. This is becoming increasingly rare in this age of outsourcing everything but our reasons are completely pragmatic. In the early days of developing our first products, all the crossovers were built using inductors hand wound from oxygen-free copper mounted together with polypropylene capacitors on ply boards and hard wired together. Of course we assumed that once the designs were finalised we would use one of the well-established OEM suppliers as has become the industry norm. But while the production was impeccable, when we auditioned the first samples it was clear something was amiss.

After rigorous checks that everything was exactly measurably identical it was clear the prototype gave a better subjective result and we decided that from that point all our crossovers would continue to be made by the same methods.

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