Thanks @grannyring I see it now.
Ok, with more coffee and less fuzzy vision than I had yesterday (comes and goes) I can see most of the circuit.
It seems that all parts are in parallel. However, 2 of the resistors are switching in or out, changing the parallel resistance from 5 Ohms (10 Ohms / 2) to 2.5 Ohms (10 Ohms / 4). Lowering the parallel resistance reduces the effectiveness (depth) of the notch filter.
This makes it most likely a shunt-type notch filter. Impossible to tell what exactly it’s doing without full analysis of the driver as well as knowing the coil and cap values.
It could have been an experiment to remove ringing in a driver, with the switch allowing for different levels of suppression.
In any event, this is clearly a DIY hobbyist’s experiment which would only be useful for his particular speaker/experiment. No use at all for anyone else. If I purchased this (I wouldn’t) it would be for experimental parts only.
This could all be confirmed with an Ohm meter. If you want to understand more about this type of circuit (or whatever it ends up being) come over to the DIYAudio / multi-way forum where we can post pictures and discuss with a number of speaker builders. :)
http://www.diyaudio.com/forums/multi-way/
Best,
E
Ok, with more coffee and less fuzzy vision than I had yesterday (comes and goes) I can see most of the circuit.
It seems that all parts are in parallel. However, 2 of the resistors are switching in or out, changing the parallel resistance from 5 Ohms (10 Ohms / 2) to 2.5 Ohms (10 Ohms / 4). Lowering the parallel resistance reduces the effectiveness (depth) of the notch filter.
This makes it most likely a shunt-type notch filter. Impossible to tell what exactly it’s doing without full analysis of the driver as well as knowing the coil and cap values.
It could have been an experiment to remove ringing in a driver, with the switch allowing for different levels of suppression.
In any event, this is clearly a DIY hobbyist’s experiment which would only be useful for his particular speaker/experiment. No use at all for anyone else. If I purchased this (I wouldn’t) it would be for experimental parts only.
This could all be confirmed with an Ohm meter. If you want to understand more about this type of circuit (or whatever it ends up being) come over to the DIYAudio / multi-way forum where we can post pictures and discuss with a number of speaker builders. :)
http://www.diyaudio.com/forums/multi-way/
Best,
E