Hello,
You can do two variants of the Bass Mod. Both are very easy:
1. Cover the front vent hole with the tape. It's not a beautiful work in my case, but I get a huge amount of very detailed (sub)bass, better isolation, smoother treble and other smaller differences.
But Watch out for very high volume. It can cause a driver flex or a leakage.
2. Make small hole to the tape with a thin needle, if the bass is too much for you or if you're afraid of a diaphragm.
I'm used to these classic eartips:
Surprisingly I can't hear any sibilences or a loss of air due to the first mod. Only a blacker background and a less forward treble, which does not have to be a bad thing.
Still, I would characterise EzAudio D4 as a colder monitors with an abnormal detail retrieval through their frequency curve.