So I am trying (very hard I might add) to design effective band-pass filters for a project. I need to filter audio into several channels, and so far I am having some issues designing my band-pass filters effectively.
I have read up on them (quite a bit, actually) and I know that there are several ways to build them, from creating the traditional Resistor-Capacitor band-pass filter, to creating a Resistor-Inductor band-pass filter, to even creating an Inductor-Capacitor band-pass filter. I have tried all of them, but I can't seem to get them within the required parameters.
The problem with using Inductors is that I need very large Inductors for the lower channels. (I.e. 20Hz) Inductors seem to be inadequate for use in circuits requiring band-pass filters lower than 1kHz. The other problem is that as I get larger Inductors, the resistance on them increases and causes signal drop problems and works against myself. (At least according to LTSpice graphs.)
The Resistor-Capacitor band-pass filter filters them fine, but I need to chain four of them together to get the drop I want, and they're not as narrow as I would like. (Graph Attached.)
I guess my question is: What is the optimum dB drop for audio filtering, and if I have achieved the optimum dB drop, how can I narrow them to get a finer tuned frequency?
Any help is greatly appreciated.
Thanks,
EBrown
I have read up on them (quite a bit, actually) and I know that there are several ways to build them, from creating the traditional Resistor-Capacitor band-pass filter, to creating a Resistor-Inductor band-pass filter, to even creating an Inductor-Capacitor band-pass filter. I have tried all of them, but I can't seem to get them within the required parameters.
The problem with using Inductors is that I need very large Inductors for the lower channels. (I.e. 20Hz) Inductors seem to be inadequate for use in circuits requiring band-pass filters lower than 1kHz. The other problem is that as I get larger Inductors, the resistance on them increases and causes signal drop problems and works against myself. (At least according to LTSpice graphs.)
The Resistor-Capacitor band-pass filter filters them fine, but I need to chain four of them together to get the drop I want, and they're not as narrow as I would like. (Graph Attached.)
I guess my question is: What is the optimum dB drop for audio filtering, and if I have achieved the optimum dB drop, how can I narrow them to get a finer tuned frequency?
Any help is greatly appreciated.
Thanks,
EBrown