May I suggest a low tech solution? Those little spungy things that you roll between your fingers before inserting into the ear canal work quite well - and the are really cheap.
I once escorted my son to a rock concert. The bass was so loud that I could literally feel it move my shirt against my chest. The high end was painful. Those little spungy things worked wonderfully to remove all pain and I was not an embarassment to my son. Can you imagine walking into a rock concert with those flight-line ear muffs? Sorry, I love my son too much to do that to him.
The little spungy things don't help much with the bass, but I suspect that those huge beasts you love don't either.
@Antedeluvian: Did you buy Joseph a pair of suppressors as well, or does his taste lean towards his mother's?
I don't know if it's just the younger generation, but Joseph seems quite happy with his earbuds in his ears -- he's impervious to anything that's going on around him -- plus in the car he tends to go into hybernation and sleep most of the journey -- he's great to have as a travelling companion because you rarely even notice he's there.
Not sure how old Joseph is, but someday he may want to see his favorite band at a local club while he is too young to get in alone. It is your fatherly duty methinks to escort him there. It makes you cool and it keeps him safe too. When that happens, please bring the monster muffs and take pictures.
I use both at the same time, the earplugs as well as the over-ear muffs often when walking through my "neighborhood", or when I sit at my open window, like when I'm soldering. The other 98% of the day it's just the earplugs. BTW, the noise ratings for the plugs and muffs are roughly comparable, if you go by the single NRR ratings.
Active cancellation isn't a total loss against lower frequecies. For instance, my Audio Technica in-ear earphones (with an IC in them from ams, which I probably stumbled on from this or a closely related blog), do an "OK" job of taking out losers' Harley noise and morphing it into the sound of a little girl's pink tyke-bike with a plastic card slapping the spokes. It's strangely appropriate that they map the noise from one with the socialization skills of an 8-year-old into a noise from an actual one.
I've never found any electronic earbuds or electronic earplugs to be comfortable when used with earmuffs at the same time, even with models of the latter that have a fair amount of clearance in the cups. They always end up pushing the in-ear things uncomfortably deep into one's cranial void.
Decades ago an old girlfriend and I used to have a rule that applied when driving -- the driver gets to pick the music, and the passenger can wear earphones if they don't like it. It was also compensation for "having" to drive. In my case it was a win-win because having her drive was a lose-lose (at best, :-)).