"In many sinarounds/informal do's, the audience seem obliged to applaud at the end of a performance, irregardless of the quality.
Therefore, most performers have no way of judging wether their efforts were good or not."

In singarounds and informal do's, I believe that applause is given for the effort made by the performer, not as an indicator of some kind of critical judgment of that performance. It's the only reward available to the (unpaid) performer.

S:0)

BTW and FWIW, 'irregardless' is a double-negative, and doesn't mean the same as 'regardless'. I fact it's the opposite - it means 'regardful' or 'having regard for'. I think you meant 'irrespective'.