Measured with the white silicone tips. I tried to simulate the sound with no vent covering at all (green line, as it would be in an acoustic coupler) and with totally blocked vents (light yellow). The other colours show steps in-between both scenarios. In my ears, the sound is between the orange and lavender line and 2 dB bassier than the DN-2000J. The amount of how much bass there will be depends on one's ear anatomy.
Please note that the level reference point at 1 kHz was measured at 5 dB at the y-axis instead of 0.