I had 24 KF760+24 BH760 last year in Slovenia.
That sounded all right, but it was a metal show, so it doesn't need that much 29 hz.
Labs didn't go that low either, pretty good to around 35hz IIRC.
I like subs with a "quick" response or kick as people often call it.
What do you recon it's "real" low frequency cutoff is?