Setting the EQ to remove anything under 300Hz doesn't really seem to have any effect. I've provided two screenshots, one has no EQ with a full spectrum visible, the other screenshot has the EQ entirely rolled off under 600, but the effect only seems to scoop the mids. Anything under around 300-200 start to become drastically audible again, with the lowest frequencies almost unaffected. There is a mild reduction in the lows/subs, but nothing even close to what the EQ should be doing at these settings.
I've tested this behaviour on the high end and roling off high freqs does seem to work as intended.
Repro steps:
1. Play some music
2. Open the EQ
3. Roll off everything at 320Hz and lower
4. Use a spectrum analyzer (or your ears) to observe no change in low end