what do you think your before and after low end frequently response is?
Hmm, I'm afraid i'm going to have to pain you a picture with the precision of crayons with my left hand:
Short Answer: its in a different league, before it was upper bass output that was pretty good with no mid or low bass filling, but now I have enough -amount- of bass, while the clarity isn't audiophile clear, it is very quick and responsive with very fast decay, and the gain + sub-bass boost known allow enough tweaking to overpower the rest of the frequency spectrum at normal listening volumes
Stock stereo had a roll off somewhere in the vicinity of 100hz, but still had some output below 60 hz enough to have certain kick drums punch, and synth sounds to be audible to maybe around 50hz ish
I am relatively treble averse and my stock EQ was +1/0/-2 bass/mid/high
after the BassPro SL:
Listening to tracks from Jamiroquai, RHCP, Linkin Park, there is a bass bloom around the 40-80hz range that can blend into the low mids and cost you resolution, but in trade, it gives you ear drum pressuring thump with the settings mentioned in my original post. Head unit EQ settings 0/0/-2
The dedicated bass boost knob on the sub lets you dial in that "boom" that car bassheads seem to like, but you won't be impressing anyone more than one car length away at the traffic lights. It is relatively tight, and the decay is nice and quick for good musicality, but the resolution of the bass is average, nothing great, but not bad. You won't be picking out the nuances of that analog 80's Korg synth just by adding this thing.
My car shop guy had it maxed on bass boost and gain, and also +3 on the head unit and it starts to break up and clip the woofer in the sub once you go above 33% on the stereo volume with the biggest EDM bass hits, so there is a definite limit to the volume output.
Of note, my sub is screwed to the carpet below the seat, but the carpet is not glued to the frame of the car or anything, so maybe some people can improve the sound a bit there, but I don't feel the need.
i don't have a frequency analyzer or anything, but for reference my home and portable audio experience:
Old school DIY 15" subwoofer for home theater using Adire Tempest subwoofer driver in a ported, filled, deadened enclosure
Headphones: Sony XB1000s, and BGVP DM6 IEMs
The overall sound is much more bassy than lets say the Grado sound profile of headphones, and more akin to closed back Sony XB's without as much head rattling sub bass below 50 hz,
In the end the stock speaker clarity and tone is still there, and i would give the door speakers a B-/B rating, but addition of the sub brings everything up to a B+/A- rating as long as i'm not critically listening to anything.
It's no miracle maker, but I just don't see how people would call this anemic, as I think it is capable of doing a good job for 95% of people without being pushed.