Hi Hark.
I've not read all the responses here so I don't know what's been suggested. If I repeat something someone's already posted, I trust it's a confirmation.
The DeCapo i is a great little speaker. We have a pair here that we use on occasion when the Sasons aren't in the music room.
Your gear is not the problem and silver based cabling, in and of itself, is not the problem.
The Decapo i is a "Constant Power/All Pass" wide dispersion design because of it's minimalist crossover and chosen drivers. As a result, it can excite room boundaries much easier if the room isn't treated and/or if the speakers/listening chair are not positioned in the room correctly. This, as I'm guessing you already know, is not a trivial matter! When you get into your new digs, take good care of the room first(!) with these speakers. Otherwise, I, and I bet Diverse Tech. can promise you'll never fully be able to realize the performance of the Decapos. It would be a shame to not give these speakers what they deserve for good set up and then blame the speakers for less than stellar performance.
As to the concern of the Siltechs being part of the culprit, maybe but like I said, silver in and of itself is not a bad system partnering with these speakers. Not only is our entire system latched up with silver, I've also modified our Decapo i with a custom silver wire harness and replaced the stock PO cap with Mundorf's silver and oil 1200v cap. The result is a more transparent high end and the entire presentation is just more effortless and rhythmic. Nothing bright or hard at all as some might assume with this much silver.
As for room set up, we finally settled on about 9.5ft from the back wall, Just shy of 3ft from the side walls. The speakers are a little over 6.5ft apart on tweeter centers and the listening position is about 7ft from the speakers. If anything in the system, including the room interaction, was going to be off-putting, it would show up in such a near field arrangement. As it is, the speakers disappear creating the illusion of the venue in the whole back part of the room. So, this is some of what's possible.
Hope this helps point a bit. I realize it may be a while but please report back when you get in your new place and everything set up good Okay?
Cheers!
Robert
RSAD