I agree with most of your points. The Eternal is a very capable single DD with terrific detail and good tonal balance. Even with aftermarket tips and cable, it's very difficult to extract any real bass out of them, however. I also disagree somewhat that the bass is "natural with proper richness." I think 7Hz missed their opportunity here to use the large 14.5mm driver to good advantage by producing satisfying and accurate bass. There are many occasions where properly-mastered tracks do not exhibit the proper degree of bass and sub-bass content, even with improved cables and tips. I am in no way a bass-head, but I do prefer to actually hear bass and sub-bass content when it's present in the mix. The Eternal falls a bit short in this department.

Also, although the staging and imaging are good, I don't feel that they're anything to brag about. What stands out for me are the details and timbre. The Eternal does a very good job at those two features, in isolation. Once you consider technicalities and the broad FR spectrum, it loses some of its charm. For $250 I think it might actually be slightly overpriced for the performance. It's a fine IEM, and it offers a slightly different take on music compared to the Timeless, but overall I think 7Hz missed out on a good opportunity here to make a truly stellar IEM. For me, the Eternal seems to live in the shadow of the Timeless.

I have tried 4-5 drivers earphone and none of them is good in bass. It is in-ear conception. Same for soundstage

Great Review mate!!