Sunday, October 07, 2007

Digital crossover

After trying so many different combination with steep/shallow crossover filters, I begain to conclude that LR filters are no good. At least within the digital crossover world, things are so flexible that I can do a bit more.

I came across a post by Uli about Bessel filter and the step response. Besel filter is a very special filter in that you can have asymmetric slope for the high pass and low pass end. I have selected to use a 2nd order for the high frequency for the mid and 10th order low frequency end for the tweeter.

I have also increase the proportion of the lower end (<60hz)>

The benefit of Bessel filter is that there is no ranging with the step response

The sound is now much faster than the LR without any loss of dynamics and the microdynamics is also excellent. My next step is to move on with linerization and DRC with this filter.

Sub: <60Hz, Bessel attenuated to 70%
Woofer: cross at 200Hz, Bessel attenuated to 30% 18dB right
Mid: cross at 2000Hz, Bessel filter - 18dB left, 12dB right
Tweeter: Bessel filter - 18dB left, 12dB right