[James Romeyn]

I got these 27-29 years ago; can't say for sure how old they were at that time but maybe not too old...exceptionally well matched for 1st order xo on Dynaudio D260 Esotar softdomes (will be padded down a few dB).

The whitish stuff on top appears to be wax.  That's a US quarter for scale.  Outer cover is brown paper w/ black paper cap at the base.  The blue pair of pigtails is 6mF, the red pair is 6mF, in other words it's a dual 6mF cap.  The "6mF" stencil on the paper wore off.

What is estimated shelf life?  I intend to keep the speakers indefinitely, like till cash out time (very healthy age 55).   

TIA!

[richidoo]

They aren't electrolytic caps, so they will last until mother nature has her way with them.  Looks like some mold spots on the paper case, so she is already started... If they still measure 6uF then there's no shorts and you are good to go.

[James Romeyn]

I've got nine of these caps; the cap pictured is the only one w/ the tiny black specks, which may be overspray from black paint employed in their proximity eons ago by yours truly.

What kind of caps are they?  They've been used several times, paralleled in large banks, taped &/or hot-glued together.  During disassembly a some of the brown paper wrap was lost, covered/repaired w/ masking tape.

A buddy is bringing his meter toward the goal of me finding 6x 5.8mF (sum total 18x 6mF in 9 caps).

This is a dumb question, but can a resistance pad be added to a cap to reduce its effective rating in a speaker XO application? 

[mgalusha]

This is a dumb question, but can a resistance pad be added to a cap to reduce its effective rating in a speaker XO application?

No. Wiring them in parallel will result in additive capacitance and series will result in reduced capacitance. If you can't find the correct combination you may need to get as close as possible under the desired value and add a small cap of the difference value in parallel. yep, I know this is probably not the desired result but if you can't get close enough with what you have that may be your only option.

[James Romeyn]

Mike
Duke is helping me w/ this project.  He's familiar w/ the following plan, but I'm anal & figure no harm in getting confirmation.

System is bipolar, 2-way, rear-firing system duplicate of front. 

Two completely separate XO's will be wired for each bipolar speaker, one XO each for front & rear firing sections.  Each XO is 8 Ohm nominal/5.3 Ohm minimum.  Two purposes are served: one is that for single amp use, the two XO's can be parallel for 4 Ohm/2.6 Ohm (nominal/minimum) for mid-high-current SS OR the two XO's can be series for 16/10.6 Ohm for tubes/low-current SS (like my amp).  The other purpose is to enable the use of separate monopole monitors for recording (front firing system detached & employed alone).

Is there anything wrong w/ the above wiring plan?   

Two 1/2cf effective enclosures per bipolar speaker: the upper enclosure holds the front firing midbass & tweeter & the rear-firing tweeter.  A separate similar 1/2cf enclosure on floor below holds only the rear firing midbass (all boxes ported; ports open for solo use/stuffed when subs employed).  A stand elevates the upper box above the lower.  When employed as a monopole monitor, the rear-firing tweeter on the upper box is not wired.