Mundorf XO Part 3, aka The Law of Diminishing Returns

This will be the last part of my writeup on Frank Fazzalari’s amazing crossovers for the Radian coaxials. It’s long overdue, and it’ll be brief.

Part 1 of this series detailed the big switch from the stock Radian crossover (built to handle nightclub loads of power), to the simple ‘XD’ unit that Frank supplies under the Radian 312 moniker. What a revelation to hear what these drivers are capable of sounding like with our little tube amps! Even the old & outdated 5215B’s I was using, sounded fantastic.

Part 2 of the saga took that up a huge notch; this saw Frank replacing the white Audiophiler MKP caps with Mundorf’s wonderful EVO Silver/Gold/Oils (the white Evo’s). The difference was not subtle. And it was well worth the upgrade cost (something like $140 above stock). Let’s call this the “Level II” upgrade, to keep things clear.

Lastly, Frank got ahold of two of the massive Mundorf Supreme Evo Silver/Gold/Oils, courtesy of Simon at Audiyo. These are over $300 US apiece(!), and they are big. As in, bigger than a hockey puck. So out came the Level II’s, and in went the big boys.


The big boys next to Canada’s largest coin, the twonie

Well, I have to be honest. In my system, in my room, with my music, etc., the sound with the Level III cap didn’t really surpass the Level II. I’m not saying they’re not better – they probably are. But in my setup, the differences were very minor. I left these in for several months, and my Radians sounded just great….but in comparison with the previous upgrade, I’d have to say the Level II mod is really the sweet spot for me. Your mileage may vary, but I’d strongly suggest you consider saving the $400-500 for other goodies, unless you’re very sure you need that last ounce of detail, or whatever. The cost is just prohibitive for the rest of us “mere mortals”, but I realize that some people have more revealing equipment and need the maximum. (“need”? really?)

In any case, there are no losers here: all of Frank’s Mundorf cap upgrades performed superbly…but at some point you have to draw a line on value, and the Supreme EVO’s crossed that line into unobtanium, for this enthusiast. I do want to emphasize that Frank’s expertise with this topic is well worth seeking out. Toronto showgoers know that he builds some incredible speakers, what most people don’t know is how helpful Frank is when it comes to optimizing crossovers.

And this also closes a chapter, of sorts. We’ve moved house, and the big Radians couldn’t come with us. They’ve gone back to their owner (Scott, with many thanks), and I miss them. I really enjoyed my time with these speakers, especially after Frank got his hands on them.


And the winner is....

And the winner is….


Again, to discuss the crossover possibilities for your coaxial or dual-concentrics, call or email Frank directly. He’s a great guy to deal with.


Coherent Speakers / Frank Fazzalari.

Contact:  Tel. 1-905-518-1240   Email:




These are Frank’s own “footers” that he gave us to try out. Also highly recommended!

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