So I'll add some more fuel to this... I was hit by the same issues the OP described on a recent recording. I wasn't using my pre-amp simply because it was a "free show" at a fair-like setting close to the lake. There was a soccer game on about 300 yards away and a concert at a Live Nation event about 800 yards away. Neither of these were my issue. There was a wedding going on which meant they didn't blast the audio as loud as they could have at the venue.
For this show, I used my CA-14/C's, my CA-UBB and the dead rats. Had the Edirol R09 set at 21 (which is usually not a problem when I'm traveling light). It sounded decent at the show and I was sure I got a decent recording. Listened to it with headphones several hours later and could hear some wavering and a lack of bass (which was also apparent at the show). When I checked it out the next day, it was thin sounding (lack of bass at the source) and the wavering could be heard.
From my experience, I chalk it up to not being close enough to the speakers (I was about 2/3's of the way to the soundboard) and because there was some wind (marginal to significant), being closer would've led to a better recording.
So, as admkrk points out... "natural sounding for being in a shit position" is what you get. Lesson learned.