I am working on replacing the Lsi25 crossover components and would like to understand the schematic more. The schematic can be found here:
On the tweeter section, I see a typical 3rd order highpass (C2, C1, C3).
On the upper driver (D1) section, I see a bandpass (C4, L2) and a Zobel (C5, R2). On the lower driver (D2) section, I see a Zobel (C6, R3).
My questions are:
1) What's R1 and C1 in parallel for? Is it some kind of a highpass filter? I found it in Lsi9 but not LsiC or Lsi15.
2) Why did Polk change R1 from 2.25 to 1.75ohm? Is it to make the tweeter louder?
2) What's L3 and R4 in series for? Is it some kind of a lowpass filter? I don't find it in any other Lsi.
3) What's the effect of connecting the two Zobel together on D2? Or, are they not Zobel at all?
4) Are D1 and D2 in opposite phase because D2+ is same as D1-?
5) Is D2 a baffle step compensation to D1? I listened to D1 and D2 separately and the volume from D2 is so much lower compared to D1 when playing the same low frequencies.
My last question is if I can list all those components in the order of importance regarding improving the sound quality? The reason for this is that I want to spend the money wisely and choosing the components correctly.
My thinking is by this order below in groups:
1) C2, C3 for the tweeter
2) C4, L2 for the midrange
3) C5, R2, C6, R3 for the two Zobel
4) the rest that I am not sure (R1, C1, L1, L3, R4)
My other thoughts are that the stock tweeter is too bright, so may not want to upgrade L1 to make it even brighter. And, since D2 sounds very low, it may make no difference to upgrade L3 and R4.
Sorry for the loaded questions. Your thoughts, advice or similar experiences would be appreciated.