Here's my take on this subject for what it's worth.
Atmosphere isn't all about who can sing the best/loudest songs throughout the match, (I used to tell my kids the reason for the singing at football is that they've nowt else to do - 'yeah dad, we know give it a rest').
If the singing does get going I enjoy it but it can't last because there's always something on the pitch to take most peoples' attention. By the way, do the musicians at Sheddingley pay to get in 'cos I can't imagine they get to see much of the match.
I read some years ago that the average age of the Wigan fans is 48, though that was probably just the season ticket holders. The singers are generally youngsters and I can't knock them for it.
For me the atmoshere is never better than when the Wigan lads are on their goal line repelling a good opposition set after set. That's when the noise gets genuinely inspiring.