I recently upgraded my Selah Audio Excelarray crossovers, with Mundorf Silver/oil caps, or I should say Rick did. Thanks again for the help Rick. First off, these caps took a while to break-in, about 250 hrs.. Until or close to that time, I was doubting as to whether or not this was the right move. They started out sounding edgy, forward, and lacked any real bass. Now 250 hrs. later, I'm as happy as a pig in mud. aa A lot has been said about the sound of the Seas Excel magnesium mid bass driver, which are used in the Excelarrays. Things like extremely neutral and detailed, but ruthlessly revealing, and somewhat unforgiving of upstream equipment and poor recordings. As implemented in the Excelarrays, with my current equipment, and the old crossover parts, (Solen on mid bass, and Theta on ribbons) the Excelarrays were capable of producing a very detailed, and satisfying musical experience. They were also very adept at revealing any equipment changes that I've made in the past. The most recent was a Raysonic tubed cd player. The reason I'm bringing this up, is to point out how the sound of these speakers changed when going from my Accuphase 65v solid state cd player to the tubed Raysonic, revealing just how supremely neutral the Seas drivers are. The sound went from having a slight edge on certain recordings, to becoming very liquid and analog like. What I've learned about the Seas driver is, you better have all your ducks in a row, before stepping up to the plate, or you might not like all the dishes you're being served. That being said, nothing quite prepared me for what I was in store for, with the Mundorf cap upgrade, not even the ravings of another Excelarrray owner who just made the same upgrade. I might have thought all my ducks were in a row, but little did I know, one of them was lame. The Mundorf Silver/oil cap upgrade has been a total revelation, and the best spent money I've ever thrown at my system, except the Excelarrays themselves. Everything, and I mean everything has taken a GIANT leap forward. Most noticeable, is the overall smoothness and warmth of the system, and although somewhat of a paradox, also sounding much more detailed. I must admit I was somewhat envious of the midrange that Rick's Galena speakers were producing at the RMAF, compared to the sound of the pre-upgraded Excelarrays. These speakers employ the Scan-Speak 7" Revelator for the midrange driver. In comparison to the Seas 7", I'd say they're almost as detailed, but deviate slightly from absolute neutrality, towards the warm side, making them more forgiving of upstream equipment and recording quality. Comparing the midrange on the Excelarrays now, I'd say they are a whole lot more detailed, and although they remain as neutral, they're now producing a deliciously natural and smooth sound, coming much closer in my opinion, to that of a live performance. Another most noticeable improvement, is soundstaging and image specificity. instruments and vocals have more space around them, and have also become more solidly placed in the soundnstage, with amazing specificity and layering. Also the frequency extremes are more extended, adding more life and sparkle to the top end, and more heft and potency to the bass. I could rattle on and on about all the improvements brought about by the Mundorf cap upgrade, but I'll stop, and conclude with a few generalizations. Although these caps are very expensive, if you're looking at reaching for the stars, you'd be foolish to think your money would be better spent elsewhere. Also if you're using the Seas midbass drivers, and think they can sound sterile at times, the blame lies elsewhere.