Amps. Most amps sound the same when operating at low levels - it is when you start to push them that they start to sound the way they sound. I have only "heard" the referance amps once, in the studio so I can't comment on them. However, I have found that crown's pro amps are very good, I have lots of use out of teh crown a 5000 ( 5000watt+ in bridge mono) running subs, and for a long time that was teh defact standard for touring. That is getting unseated a bit by QSC and the powerlight series though (PL 9.0 and 6.0 at 9000watts and 6000watts respectively).

What I can tell you for sure is that the amps are like the 1 bit that has teh LEAST impact on sound. - converts in teh CD player (and the clock they use) does make a differance, but the top 2 most imporant parts are room and speakers.

if I had to rate them-
45% - room
35-40% - speakers
7-10% - cd player - or record play - or 8 track......
5% - amp
.001 % - use of fancy cable sets

if you want to see wht you are hearing get a 40$ mic (ecm8000)and get teh demo for sia smarrt.

any way its late talk to you later.