pg rsd5cs x over modification for bi amp

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 = resistorI = inductorC = capacitorR1 - 10W3RJ R2 - 5W2RJR3 - 5W1RJI1 - .184mh/.8mmI2 - .208mh/.6mmI3 - .126mh/.6mmC1 - 6.8J 100V METC2 - 6.0J 100V METC3 - 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!

It sounds like you are going a mile out of your way for limited to no benefit. You are just dividing the output from your HU. The only advantage would be having level control thru the fader knob. If you had multiple dedicated amp channels plus an electronic x-over you would be biamping, hence no need to modify the passive. IMO you would get better performance using a separate amp and running the comps passive. Enclosures in the doors, try listen to them as in infinite baffle before going breaking out the resin.

I understand that a separate amp is the way to go but I don't have the money for it. As for dividing the head units power that doesn't make sense to me. It seems that using all 4 channels would provide more power to the speakers which would be along the same lines as using an external amp in the sense of providing more power to the speakers will operate better. The head unit does have fader and balance controls along with x-overs, time delay adjustment, speaker position adjustment, 4 band EQ with selectable frequencies for each of the 4 bands so to me this seems to be a lot of functionality. It is very basic when compared to using an external amp, active x-overs with the passives, and a real EQ but again I don't have any more money to spend. I would try dropping the speakers in directly but the doors don't seal well and I will already have to modify them to fit the speakers. Also the door panel material isn't in good shape so I figured why not kill 2 birds with 1 stone and do something creative. On a side note I have a 1990 mustang hatchback. Back in 03 I had a 91 mustang hatchback that I put CDT carbon fiber components which were in between their entry level and mid levels supposedly and they were basically IB in the doors and sucked. They too were ran off the head unit although that was a cheap Boss Audio unit. For that set up I also had a Pioneer entry level 12" sub with a 300rms Profile amp but I build an ABC ported box for it and the stereo shop owner who I worked for briefly was so impressed by it running off the stock radio using a high level input that he gave me the Boss radio so he could hear what it would sound like with an after market radio. More or less he told me that it sounded like a $400-$500 sub with more power than what the amp was putting out. I'm not trying to ignore your suggestions, I just like being creative.   I'm sure the speakers sound great on their own but why not push it's potential? As far as money goes, the door panel thing is only in the works because I already have all the stuff needed with the exception of about $10 worth of materials and yes I really am on such a tight budget that I can't afford even a $60 amp which I'm pretty sure those results from a $60 amp can be achieved by re-working the x-overs to use 2 channels each instead of 1. Even if this all sounds like crap or not really worth the effort for you, I still would like to try but I am really curious to know if my ideas on how to split the x-overs is correct or not. Thanks for the reply!

Ahhh.... a man after my own heart! :) I went all active, and tri-amped for my doors alone! It's worth it, I promise you! Audiocableguy, whether he is using a proper "external" amplifier, or the deck amplifier, he IS bi-amping. The deck will have 4 chipped channels within it, and one chip will drive each driver - the very definition of bi-amping. Now... Meltmanbob, the difficulty you are going to run into here, is that the negative terminal is common throughout the crossover system. You cannot use all four channels of a BTL deck with a common return. You will fry the deck. The crossovers also do not allow multiple amplifier channels to connect. I understand completely what you are trying to do, and you may or may not gain anything significant, (especially using deck power) but the speaker system you chose was not ever going to allow you to bring your plan to fruition. With a single input, and a common return trace throughout the crossover, it's never going to happen with a deck amplifier. (Actually, it's never going to happen with ANY current technology amplifier.) If you were to remove all of the individual components from the PG crossover, and build dedicated crossover boards with ISOLATED return traces for both tweeter and woofer, you'll be diamond! :) ##########EDIT########## I mentioned current technology. Any four channel, bridgeable amplifier will work, but it MUST be an external amp, with a proper DC-DC power supply within it, and it cannot use "chip" outputs. It could be made to work.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

"Audiocableguy, whether he is using a proper "external" amplifier, or the deck amplifier, he IS bi-amping. The deck will have 4 chipped channels within it, and one chip will drive each driver - the very definition of bi-amping." Yes, I understand this. I was leading to: if the deck allows for the correct x-over frequencies he would not need the passives.

From my understanding active xovers in the simplest sense will cut off the frequency instead of using a roll off effect like a passive but this is just my assumption as I have never looked into active xovers yet. Also passives offer other attenuation if that is the correct term such as in the PG xovers having a series notch filter for the woofer which according to PG's xover guide the SNF smooths out some unwanted inherent characteristics of the driver. I kinda figured that if I tried to use a common ground/negative return that the returning signals would mix at this common point and cause problems like frying the head unit. So if I want to do this it looks like I need to completely isolate the tweeter and woofer circuits from each other by using separate positive AND negative leads that go directly too and from the head unit. With this in mind and for the sake of keeping the current circuit board I would prefer to buy 2 individual pairs of terminal connections and cut a small hole on the side of the xover case, mount 1 extra pair to each xover and remove the appropriate components on the board and hook them up to the extra terminal pair. Eureka!! Corny I know but I think I just realized how to do this without having to add more terminals. In theory if I would need individual positive inputs for the tweeter and woofer which would be connected to their respective 1st component in their individual circuit which is then already tied to the rest of their circuit. Each driver would also need an individual terminal to connect the positive lead from the driver but the ingenious thing is that both drivers end their circuits in parallel with a circuit component which means the negative driver lead and negative input lead for it's individual circuit can be tied together on one terminal. This means that each driver and it's circuit only need 3 connection terminals and there are already 6 on each xover board so now I just have to figure out how to re-do the board. Granted you could have individual terminals for the driver's negative lead and the negative lead for it's circuit from the head unit but since they end in parallel, the backside of the circuit board would show that both terminals are electrically connected. So if you don't mind connecting 2 wires on 1 terminal then you can do it with 3 which to me is a decent trade off for not having to modify the housing assuming I can re-work the board appropriately. Now that that's settled I think, can anyone clarify the markings on the xover components for my curiosity? Also I would like to hear more info, advice, thoughts or experiences regarding the custom door panels whether it be about the panels, speaker enclosure, ABC boxes, or anything about the RD65CS that might help or be good to know. Thanks a bunch guys, this has already helped a lot!!!!

Hey if anyone wants some drawings I would be happy to provide them so long as they are posted in the thread for me since I don't have those privileges. Right now I have a pretty close to scale layout on graph paper showing the front of the xover components, a backside view showing the circuit board etching that is mirrored so it matches up with the front drawing as if you could see though the board. I also have a circuit diagram I drew of the factory layout and a separate drawing for the individual driver circuits. I'm currently analyzing these to see if there is a neat and simple way to re-etch the board on certain points to achieve isolated individual circuits.

Ok it looks like all I would have to do is cut through the conductive layer 4 locations and make 1 jump to achieve individual circuits. It's hard to explain without drawings but I'll try. H.U. = head unit W    = woofer W.C. = woofer circuit T.C. = tweeter circuit T    = tweeter +    = positive -    = negative Functions below start with left-most terminal on xover then moving right. Factory Terminal (F.T.)        New Terminal (N.T.) 1) H.U. -        H.U. W/W.C. - 2) H.U. +        H.U. W.C. + 3) W -           H.U. T.C. + 4) W +           W + 5) T -           H.U. T/T.C. - 6) T +           T + 1) Terminal isolated by cutting conductive layer in 2 places so only the terminal and R1 stay connected. 2) Terminal isolated by cutting conductive layer in 1 place so only I1 and the terminal stay connected. 3) Terminal isolated by cutting conductive layer in 1 place so it is not connected to anything. Then bridge it to the conductive layer containing R2 and R3 which should be isolated together from isolating terminal 2 in previous step. 4) Terminal already isolated, nothing needs to be done for this one. 5) Terminal already isolated with I3 from steps involved with terminal 1 and 3. 6) Terminal already isolated, nothing needs to be done for this one. Again if anyone is willing to post the drawings I will transfer them into Google's SketchUP program and take snapshots. SketchUP is a basic C.A.D. program. Also if someone is willing to post the drawings I would appreciate it greatly if someone could double check these steps. If I go through with this I plan on using a razor knife to split the conductive layers by cutting/scratching a separation line and then checking resistance to make sure. For the one jump that needs to be made I was just going to use a very short piece of wire with only about 1/8" bare copper at each end and soldering it where needed. Does this sound like a good plan? If all goes well it will just mean that the labels on the plastic cover won't be accurate with the exception of 2 terminals and the one jumper would be on the underside with the cutting marks were they are not visible. I guess if I really wanted to I could scrape off the old labels, make a stencil with new labels and spray paint them on to match. P.S. I figure it would be a good idea to say that I am not trying to encourage anyone else to do this and that if anyone wants to attempt this they should do so at their own risk.

No... your understanding of active crossovers is mistaken... Active devices still have a roll-off, just as do passive devices. You've heard of 24dB/- or 16dB/- octave? That's the roll-off, and is the number that describes how fast the attenuation is from the -3dB point. If you have a 1kHz 24dB/octave crossover point, 1kHz (the "knee") is 3dB quieter than zero dB, or reference. At 500Hz, one octave below 1kHz, then the output at 500Hz will be 27dB off "reference" or 27dB quieter than reference. In your passive crossover boxes, if there is ANY electrical connection between the woofer's low-pass and the tweeter's high-pass circuits, you cannot use them with your deck, so if you decide to go this route, be extra cautious with your internal connections and the drivers or the deck.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."

Cool! Like I mentioned I would be checking resistance to see if I completely cut the circuit the way I intended and I might even apply some sort of coating to eliminate the possibility of electricity jumping the gaps. As for the active xovers like I said I've never looked into them. I am familiar with the roll off associated with 1st, 2nd etc ordered passives, I just wasn't sure that actives behaved the same way. Do you have any thoughts about the door panel idea for the woofers? Also if you don't mind a brief explanation I am now a bit interested to know why actives are generally thought of as being better.