Is it possible: passive subsonic filter?

Geez

Member
2005-01-16 10:08 am
a
Hi!

I was wondering if someone has already built a subsonic filter to prevent excessive cone motion.

Using BassBox 6 at the External tab in the Driver Properties window I could experience with capacitor and inductance values but it looks like I would need 200-1000 microFarad and 20-60 mH (3-8 Ohm DCR) values which are very expensive.

As long as I read on other forums that they sell Behringer 2×3 way active crossovers for $200 I'm not shure the passive is the right choice.

Daniel:xeye:
 

Geez

Member
2005-01-16 10:08 am
a
Thanks for the reply's.

In Thiele's calssic paper he writes about the passive filter assisted bassreflex alignments. If a passive low frequency high pass filter is so expensive then these aligments: B5, B6, C6 are not good choices I can conclude.

Daniel
 
re passive filters

If you are making your own power amplifier you can get a second order high pass filter by choosing the value of the input coupling capacitor, and the capacitor that shunts the feedback leg to ground. This has a fixed Qt=.5, and is suitable as a part of the SC6,C6, QB5 class III alignments.
If only a single capacitor can be used then this can be part of a B5 alignment, in practice a back to back pair of electrolytics that has a nominal total capacity of around twice the one called for in theory will give a result that only varies by a few db. from the ideal if put in series with the driver, this can also be used as a second order filter if you choose an input coupling capacitor that is equal to the theoretical value.