Acoustic Zen Crescendo speaker crossover capacitors ... who makes them?

@pbnaudio and others. The two 8 inch woofers are parallel wired. I have drawn out the circuit and taken photos of the board. Please take a look. The 1000uf caps, smaller inductor, and 8 ohm resistor all seem to be included parallel to the amps output to raise the impedance of the bass filter. Two 8 ohm woofers in parallel would deliver a net impedance of 4 ohms. The builder wanted to keep the speaker friendly to tube amps and thus implemented this impedance filter. The speaker is 6 ohms nominal.  I am not sure if this impedance filter reduces the impedance peaks of the vent/port and drivers or raises the nominal woofer impedance the amp sees? Or both? 

Question. Will the quality of the parts in this impedance filter impact bass quality? On paper it seems like no, but I know from experience they can very well have an impact on sound quality. Thanks in advance.

http://s1097.photobucket.com/user/grannyring1/library/Bass%20board%20crossover

Looking at your schematic, you have a impedance correction network across the positive and negative, not knowing the value of he inductor is impossible to tell, you where it corrects, you could disconnect it measure the impedance and see where you get a raise in the impedance.  Changing the caps or bias them in this circuit will not do much to SQ but you could certainly try.

The woofers are connected to a standard 18dB/Oct electrical filter consisting of two coils in series and a 200uF capacitor as a shunt via a 12 Ohm resistor between them, pretty standard stuff. However parts seems to be a extraordinarily high quality. 

Best

Peter

Peter thank you so much. I will leave all alone except upgrading the sandcast resistors. 

The caps are Taiwan or were .I have Never known them to use name brand 
On the few Adagio and crescendo over the last 5 years. They still sound very respectable with a Xover upgrade with boutique caps. 
In thd Bass just put in a bunch of poly bypass caps Solen would ge good enough. 01uf 400v would be fine that would  clean it up a bit. Good Copper gold or rhodium loudspeaker terminals another easy fix.  
If you are open to spend around  $700 while you are replacing the Loudspeaker terminals VH audio has a special. 2 years ago these were $ 1300.
Bybee Golden goddesses on the hot side and then  black ones  on the minus. 
I guarantee you a more detailed quieter backgrounds and just more real soundING. I did these for a friend, I am more surprised at the results and I Allways do upgrade mods. First read a few reviews these were $4k when they first came out. They replaced the 24k hold with a matrix of things. Your call.

I recently emailed Robert Lee, owner of Acoustic Zen, telling him that I was following a thread on Audiogon where certain people had upgraded the crossovers in their Crescendo speakers with superior boutique parts with excellent results. I didn't mention any names. I asked him if he would give me a list of cap and resistor values of the Adagio so that I could experiment with upgrading parts in my speaker crossovers. His response was basically, " Please don't mess with my crossovers. They are perfect the way I have designed them. I don't know why they want to change it. I would recommend that you experiment with speaker placement and room acoustics. Please call me for recommendations. Email me photos of your system and room." I thanked him for his response, but haven't followed up with him at this time.