I think for us there are several factors/reasons that led to a relatively quiet Camp Nou:
- The relatively small number of the Animation Stand and the lack of Barca ultras presents at Camp Nou regularly. Yes they are there but their numbers look really small to me compared to those of other clubs, especially those in Germany. You can hear them sometimes but by no means are they that loud, not as loud as the other ones at leas.
- Camp Nou is simply huge and almost never full, you only get between 60K - 70K on average or so generally, many local fans are just kind of pretty laid-back from my observations, almost kind of like some American sports fans, not as engaged as other fans. Chatting, talking, eating etc. Ticket prices might have played a role. If they are cheaper, perhaps more local fans will show up.
- Relatively large number of "tourists" or "international fans". Many of them are very passionate, perhaps more passionate than some local fans but most of them are pretty quiet, they don't know how to sing the club songs in Catalan and they don't react to what comes through the PA system etc.
- Ultimately I think it is what Neeraj said, many socis and local fans simply don't care that much. Why? We don't know.