I have Audacity, which I have used in the past for spectrum analysis. I tried using that program before Audition, but couldn't figure out how to split the raw file into tracks, and gave up and fired up Audition, and I was able to figure out the basiscs of Audition much faster so for now I'm sticking with it.
The reason I considered the LCF on the M10 was that earlier in the day yesterday, I did a test recording of a track playing on the computer (Pendulum by Broadcast, which is a very bass heavy track, and with levels peaking at -4, the bass was heavily distorted. With LCF on, it sounded a whole lot better. Looking at the natural and LCF spectrum analysis, the LCF cuts about 20db off the lowest frequencies, and rises up to 0db reduction at 250 hz.
Anyway, after seeing your comment, I tried to see if I could correct the distorted bass recording I had made, and ran it through the setting on Audition's Parametric EQ "Generic High Pass fllter" and the bass level was reduced, but it still rumbled, albeit at a far lower level, in a way the original track did not, and playing with the EQ curve, I couldn't get the rumble of distorition to go away without making the track sound thin from insufficient bass. My failure might be my inexperience in working an EQ. It did sound better after applying the filter in post, but I think the version I made of Pendulum with the LCF on, then with the EQ tweaked to amplify under 300 hz bass by 5-10db, sounded better than anything I could do with the distorted one.
I don't think every flaw can be corrected in post, otherwise we'd be able to make good recordings out of any defective source, which is plainly not possible. I see that modern tools can improve a distorted original, but it seems that they don't improve it to the quality you'd get from not having distorted at all.