yeah trust me, it's not my insertion depth. Looking in the mirror, the whole of the ER4's body as well as the tip of the connector are vanished. If these have to go any deeper, than I don't want to find out.
Great thing is that the ER4 responds very well to EQ like you mentioned. Probably why you like them so much for monitoring. And the lack of bass definitely isn't from the driver running out of steam. You can turn these bad boys into some bass monsters (w/o the distortion) with the right EQ.