Didnt run them that high but there is a bit of output. Deff hard drop off at 50hz plus but what do you expect tunning that low. Show me a sub that will play the entire sub freq flat in a ported setup. One that will play down to 25 up to 80 well
I can show you LOTS. Anything with a well designed shorting ring should be able to do it. Only reason many "high end" car audio woofers can't is because of what car audio guys consider "high end' (notice I keep putting quotes lol) subs to be like. They use super stiff suspensions that lower effeciency and cause lots of mechanical noise, massive motors and coils, but use no faraday rings to control inductance. This leads to MASSIVE drop off above 60 which leads to them being useless for music.
My last subs were AV15h's. They use faraday rings to control inductance to VERY low levels. If they used a paper cone and not metal, they could easily play up to 2000hz without issue. Metal cone limits them to 500ish before cone breakup. Regardless , I was tuned at 25hz I used them crossed over at 125hz@24db/octave. Any higher and the trunk began to muffle the output too much. They were playing over 2 octaves of music and while I never metered it, to the ear, it was fairly flat and very musical. You could feel your clothes moving a bit on 60hz kick drum notes and using tones their was FAR more output capability than you'd ever get from a "midbass" from 60-100hz, 80hz modulated your voice when speaking.... Just had to cut at 40-50hz a tad due to cabin gain. My preference for frequency response is similar to the few above.. I like flat to the ear from 80-40 with a rising response below that, can't have too much low low's lol. Really in a car though that's what you want. Flat on a RTA has nothing to do with sounding good, when your talking about anything below 200hz or anything above 4000hz. Beyond that most people prefer a sloping response and it sounds more realistic, especially in a small environment.
Without at least 120db's of midbass output your not going to sound remotely close to flat on music doing a mid/low 140. My next setup will be 2 21's. B&Cs 21's. They use a 6" voice coil, have a conservative power handling of 2k a piece AND can easily play up into the midbass region with 97db/1w/1m of output.. Easily capable of 130-140db of mid bass as a pair of them, and probably nearing a 150 from 30-60hz on music, probably even larger range in a 6th order. Point is, you CAN be loud full range, just takes a different type of beast than most car audio subs. I know sundown has started using faraday rings, but the last few subs still haven't made it above 60hz very well yet, IIRC.