I bring you: the vhs.
It is your number one source for smoothening, and distorting a track
1.get a vhs tape
2. get a vcr
3. get a headphone jack to red/white converter
4. record the track onto the tape (not too loud it will distort... unless you want it to distort it.)
5. get a mic jack, or usb to mic jack converter
6. record the vhs tape music back onto your computer
7. congratulations, you've made lofi!
you can use this track for just the bass and add it to the original,
or maybe the mids, or highs,
or maybe a distorted delay.