Proac D18 + NACA5 = This week's catastrophe. Am I doing something wrong.....

....or is the combination really this bad?  Bit of back story, I've had the Proac D18s for about a year, driven by SN2 and DAC-V1.  The speakers represent my only auction site punt, so I'd not auditioned them, but they showed much promise, and were performing well overall.  However, I have always found them tad bright, and a little edgy on vocals in particular.  Note there I said a tad too bright.  I added 4m runs of NACA5 this weekend to replace my 20 year old QED biwire, hoping it would beef-up the mid / lower mid, and perhaps a little HF roll off, but oh dear.  I mean, no no no.  It's so bright now, and all but the very woolliest recordings sound anorexic.  The top end frequencies are well behaved, as are the very low frequencies, but there's just barely anything in between, all top and tail with no guts.  Man, it's lean, actually that's understating, it has become a zero fat, no sugar, two veg and no meat of a system.

Has anyone else found similar with the same speakers in a Naim system?  Is there some school boy error I could have made with the cables?  I am now using the Naim plugs for the first time at the amp end, and there are gold plated Chord plugs at the speaker end; these were made up by my dealer.  For the moment I've used the bars supplied by Proac to bridge the terminals.  I can't think what could be a miss with that, at least not that will make a huge difference to the overall performance, but open to ideas.

I think the Proacs will have to go, which is a PITA, unless anyone has some bright ideas.  Taking the D18s as a starting point and declaring them too bright and gutless, I would be keen to hear some recommendations of speakers that are much richer sounding with Naim gear.  

Cheers