Mystery Capacitor and the Tangent RS4 Crossover

@imhififan That is good news to hear your take on the value. The cap was somewhat damaged as I removed it from the circuit board so I was just a bit concerned about whether it would measure accurately.
@timlub What kind of speakers to you build? Do you do this professionally? I also built my first speakers in the 70's, 6x9" with whizzer cones in a shoebox sized wooden cabinet and lamp cord to be used as external speakers run by my parents protable record player. Can't say I pursued it much further when I got a chance to buy some used AR2's I was a happy camper.

Hi, @bruce19 I started modifying speakers when I was a store manager at CMC Stereo. I visited the audiophile shops in the St. Louis area regularly. We had a retail store called SpeakerCraft that custom built speakers. In 1980, I took a job as General Manager at SpeakerCraft, we had a division called Marcof Electronics, we built Moving Coil head amps, cables, modified cartridges, tables and built several Amps and Preamps..
It was there that I established a fairly in depth knowledge of Speaker Design. I had a good enough foundation that over the years, I was able to expand my knowledge to a complete understanding of speaker design. The owner there had and still has a full knowledge, but when I left, I just hadn’t absorbed it all yet. I have done hundreds of repairs and builds in the past years, even here on Audiogon, I have done several modifications, a couple of repairs and a couple of designs for members. In my Listening room, I currently have an MTM with 6.8 inch woofers and a dome tweeter, I have a 3 way with a paper cone 10 inch woofer an aluminum 5 inch mid and a ribbon tweeter, I have a pair with the top end Heil AMT with a 12 inch woofer and I am currently enjoying a 15 inch woofer and 1 inch dome in a 2 way. These speakers are 86 db 4 ohm, 87 db 8 ohm, 94db 8 ohm and 95 db 5 ohm. So, that’s the best I can answer, what kind of speakers I build... As far as professionally building. My 15 inch 2 way turned out so radically good and most audiophiles would not believe a 15 and dome to be able to sound as it does, that I truly explored going into manufacturing. I bought domains, registered a name, but no shows, my industry contacts are as old or older than I am or worst... Dead. So, recently I bailed on that Idea.

Smart move. Many years ago I was in the same situation only with turntables. Used some connections, pulled some strings, got into CES as a vendor with a (very) early prototype. That one long weekend seeing what the business is like from the inside turned me off so much, and happy for it, saved me what would have been an awful lot of emotional and more than likely financial pain. The idea that if you build a better mouse trap the world will beat a path to your door is so laughably off it could be a feature length Monty Python movie.

@millercarbon
I hear ya, I have been to at least 20 C.E.S as a buyer, not as a vendor. Even on my end, it was easy to see how cutthroat it could be from the vendor side. Years ago, Randy Patton who briefly owned Threshold, Sumo, Meitner, PS Audio and a few others, recommended me to Martin Logan. I had a call from them asking me to come interview in Kansas. I had no interest in moving to Kansas and did not go for an interview, but that started me thinking about doing my own thing. I would still love to produce speakers, but as I eluded to earlier, I’m getting older. I would love to market this 15 inch 2 way.... At this point, not likely.

@timlub Your 15 inch/1inch speaker sounds interesting, particularly coupled with the efficiency rating it sports. Have you considered selling it as a DIY kit? I was looking around and was surprised at the lack of selection of DIY speaker kits. Maybe a part of that problem is related to the fact that audio reviewers generally  ignore kits. For instance if I had not come across reviews of the amp camp amp and the bottlehead crack headphone amp I would not have even considered kits. As it was I did build a Amp Camp Amp and am working on a second because it was fun and it sounds really good.I think that the urge to build and tinker is under exploited in this hobby. Too many people just think it is all about going out and laying down large sums for beautifully finished final products. There is nothing wrong with this mind you, but you don't learn anywhere near as much as when you get more involved.I for one might very well be interested in building a version of your speaker if it were available.