I like the idea of special flat NR reduction earplugs for music venues and have had some in the past, but so far all the versions I’ve seen have less noise reduction than regular earplugs. It’s not an unreasonable compromise, but I generally want maximum NR whenever I use earplugs even though it means loosing musical clarity 
. Venues really get that loud (and sometimes you can even see the front of house sound mixer wearing earplugs :-0 )
