FDS-366T Bessel filter implementation

arnaudf

Dear BSS,

Since a few months, I own a FDS366T processor to filter my loudspeakers (2-way + biamping).
I already tried several filter setup (Butterworth, and L-R). I'm now trying the Bessel ones (particularly the 24db/oct).

However I need some information about their implemation in the 366T.
For example, how are they normalized ? (this Rane technote shows there are many ways : http://www.rane.com/note147.html)
I already remark that cutoff freq are based on -6dB, but I'm note sure...

I'm look for Bessel filters with the most possible linear phase and summed freq response.

I use an Excel sheet to simulate Bessel filters and it uses -3dB cutoff freq. In this case LPF and HPF are different.

Regards,
AF.

arnaudf

I answer to myself...

It seems that I have a beginning of answer.
Following the filter curves published in the \"original\" 366 manual (page 20), it seems that the crossover point for Bessel 24db is located around -7,5dB...

Thus the multiplying factors in the Rane technote seems to be ok (see § \"Rane's Bessel Crossover at -3 dB\" ).

arnaudf

Finally after some testing the factors does not match for the 366.
If a gentle BSS engineer or forum guy have an idea, they are welcomed...

komp

The forum is half death as you see, its sad because I have many products from them.

It would be nice if someone solve your problem

davidcbradshaw

If you require technical support, these forums are not necessarily the place to get it, they are, as the name alludes- a user group- not a route to technical support.

There is a cunningly titled 'support' page on the BSS website that will allow you to send a message directly to a technical support person in your timezone.