Hi this is my first post on this site and from the little searching I did it seems like there are more knowledgeable people here that might help. The first part of my post is a little explanation and then goes into an off topic which is not my main focus but please take note of the resistor, capacitor and inductor labels I provided below (section divided by ~~~~~) so it's easier to follow the circuit. The main focus of this post is below the line of @@@@@ symbols. Thanks for your time!
I recently bought a pair of Phoenix Gold RSD65CS components and I have a Kenwood KDC HD942U on its way which will power the speakers. I would like to modify the crossovers that came with the speakers for bi-amplification off the head unit; tweeters on the front channels and woofers on the rears since I don't have an amp to power them.
The x-overs I believe are "2nd order" but from looking at them I believe the tweeter actually has a 3rd order and the woofer has a 1st order with a series notch filter. It's been a while since I've read up on any of this stuff with the exception of today so I was hoping someone could double check my thinking and help me work out any details.
The x-overs have 3 of each capacitor, inductor and resistor. The resistors don't look typical to me but a google search and some reading suggest they are cement type resistors.
This part I don't believe is really important for what I want to do but out of curiosity if someone could explain the markings on the components I would appreciate it.
~~~~~~~~~~~~~~~~~~
R = resistor
I = inductor
C = capacitor
R1 - 10W3RJ
R2 - 5W2RJ
R3 - 5W1RJ
I1 - .184mh/.8mm
I2 - .208mh/.6mm
I3 - .126mh/.6mm
C1 - 6.8J 100V MET
C2 - 6.0J 100V MET
C3 - 9uf 100V NP
~~~~~~~~~~~~~~~~~~~~
From my google search I am assuming R1's marking means it resists 10 watts @ 3 ohms, not sure what the 5 is for and the J means it has a tolerance of 5%. I did read that the R might be the equivalent of a decimal making it resist 10 watts at 3.5ohms with a tolerance of 5%. Am I even close to understanding? I don't understand why R2 and 3 are without a number between the R and J in the markings.
I don't understand what exactly the 6.8J or 6.0J means on the capacitor except that I'm assuming it has to do with it's capacitance like the 9uf marking on C3. I also don' get the MET or NP but I'm guessing those are either brands or the type of capacitor.
On the inductors they seem pretty straight forward except the /.8mm or /.6mm but I'm guessing that is the diameter of the wire used in their winding.
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Back on topic - I sketched out the circuit physical layout and then was able (I think!) to figure out how this was organized with some helpful reading on the phoenix gold website archives on crossover design.
It appears that the Neg. (negative) input, Neg. tweeter and Neg. woofer terminals are all tied together in parallel if that's the correct way of saying it. The Pos. (positive) input branches in parallel 3 ways. One to I1 and the other two to R2 and R3 which are in parallel together connecting to the tweeter attenuation switch for +0b or +2db. R2 appears to be connected to the +0db side and R3 to the +2db side.
Out of the tweeter switch in series is C2 which branches to I3 and C1 which are in parallel to each other. C1 goes to the tweeter Pos. terminal while I3 joins back up with the Neg. input.
Back to the initial 3 way parallel branch off the Pos. input. 2 of the 3 branches were R2 and R3 for the tweeter which leaves I1. Out of I1 it branches in parallel to the Pos. woofer terminal and t C3. Out of C3 in series is I2 and then in series out of I2 is R1 which finally ties back in to the Neg. input.
Based on the diagrams and descriptions at the PG website it appears that the "tweeter switch" literally switches between using R2 or R3.
So in short it looks like the Pos. input goes to the tweeter circuit which is the tweeter switch set up which then goes to the 3rd order filter (I assumed that is the filter because it looks like a series capacitor then parallel inductor and then series capacitor. The Pos. input also goes to I1 which appears to be the woofers 1st order lowpass filter with the following C3, I2, and R1 all in series being the series notch filter.
Ok if this is all correct then I believe bi-amplification should be as easy as unsoldering the end of I1 closest to the connection terminals and hooking it up to the rear right or left Pos. out from the head unit. I'm not sure about the rear Neg. out. I'm thinking I could just connect it to the same Neg. input terminal already on the x-over like in electrical construction sharing grounds but then again I'm thinking the Neg. out from the head unit rear should go directly to the woofer circuit so the returning signals don't mix and damage the head unit somehow. Which train of thought is correct?
Thanks again!!!
P.S. I'm building new door panels, partly so I can provide a better enclosure for the new speakers but I am toying around with the idea of fiberglassing a very small ABC ported box for the PG RSD65CS. So far I'm looking at .3-.5cu ft tuned to ~55hz for an infinite tune to ~100hz. It should add a little between 100-300h and provide between a 1st and 4th order high pass effect starting the decrease around 120hz. Any thoughts, suggestions or comments appreciated!