http://pinknoisemag.com/essays/the-art-and-aesthetics-of-audio-restoration

this is a bit different from archival work, but interesting. I would say, if Spec Brothers says a 
DAT is not recoverable, it's toast.

One thing I noticed -- after all the details of what she did, and a link to buy the music -- no 
examples. That makes me suspect that despite all the processing, or because of it, the sound quality 
is poor. This may be completely untrue, but I'm not going to risk cash to find out. They should have 
put some sample audio up.

-- Tom Fine