New bass strings, some dead

[Mike Spalding]

I am restringing a 30 year old S&S L for the local university.  Just 
installed the bass strings today, and 5 of the 42 have a noticeably 
duller/deader tone than the rest of the set.  The dead strings are not 
contiguous - there are bright lively strings in between the dead ones.  
In fact, 4 of them are one string of a bichord, where the other string 
is good.  We're listening to plucked strings, since I don't have the 
action.  The whole piano is chipped more or less to pitch.

Original bridge cap surface planed smooth, bridge renotched, new bridge 
pins set in epoxy.  Original agraffes reamed with pianotek reamer.

Is this for sure a case of defective strings, or are there some things I 
should check before contacting the stringmaker?

thanks

Mike