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

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. 

Sherod, I have sent him my before and after pics and asked some questions, but no answers or responses since his first initial response.

You can do it yourself easily. Your speaker is not as complex. Several great on line pictures and examples of others upgrading the speaker. The values are printed right on the caps and resistors. Easy to see and order! Don’t change out the inductors and order the parts matched within 1%. The Mills MRA resistors are already within a 1% tolerance. They are only $4 each at Sonic Craft.

I just finished my bass board today. They sound so much better after the upgrades! All owners would be so pleased and impressed with the NEW speaker!

Be sure to use two MRA12 resistors in parallel when replacing 20 watt sand cast resistors. For example you need to replace one 8 ohm sand cast 20 watt resistor with two 16 ohm Mills resistors in parallel. You can replace the 10 watt sand cast with one Mills MRA12 as they are rated for 12 watts. The sand cast resistors are clearly marked. Get those sand cast out! All of them must go.

I can tell you the speaker is so much better sounding after the upgrade. I thought they were wonderful before, but now I know what I had no idea I didn’t know:)