Fully taping helps a bit you’ll gain around 2dB more sub bass at normal listening level.
The S12 has 2 vents
which I taped masterfully for science
I recorded the same track at same volume 1x taped and 1x untaped. Then I checked the audio spectrum in iZotope RX7. There I looked at the dB amplitude of the first strong bass impulse at around 40Hz.
Untaped (amplitude = -24.7 dB):
Taped (amplitude = -22.4 dB):
So in this scenario I gained -22.4 dB - -24.7 dB = 2.3 dB
and finally the sound demo: