I have a proper Tektronix FR generator both are perfectly equal, they are just not "quite" weighty enough in the bottom end for me, which makes them less "meaty" in the prestation to what I like, which gives gut, body, and musicality to things like cello's etc etc
If 50Hz sounds audibly "perfectly equal" in level to 500Hz but you don't feel that's enough, you are used to ridiculously boosted bass levels.
But also, there is no conceivable way if you do that same test on your non-sealing earbuds you will get 50Hz at the same level as 500Hz. I just don't believe that's physically possible due to the inherent sub-bass roll-off of non-sealing earbuds, combined with the way human hearing works, for sub-bass to sound
at an equal level it actually needs to be quite substantially boosted as our hearing is less sensitive in low sub-bass frequencies.
So this simply doesn't make any sense. Even with IEMs with a substantial sub-bass boost, due to loudness contour of human hearing, 50Hz pretty much always sounds lower than 500Hz. It sounds lower to me on the Chu 2, the point of this test is not so much they have to be exactly equal but that if you have a seal break the 50Hz will drop off dramatically. Yet you are saying it's perfectly equal on non-sealing earbuds? I went and tried this test myself with Fiio FF3 earbuds which are probably the bassiest that I have, and while 50Hz was audible, it was at a much lower level than 500Hz.
I don't think you are actually understanding what people are saying to you or trying any of this. How does your "proper Tektronix FR generator" make any difference to testing whether 50 and 500Hz sound the same? You think you need sophisticated lab equipment to compare a 50Hz to a 500Hz tone?
Did you actually go and compare a 50Hz tone to a 500Hz tone? Or are you missing the point and saying that the left and right sound "perfectly equal"?
Did you actually try pushing them in to see if the bass increases? You just repeat that you tried the different tips in the box. But maybe none of the stock tips sealed for you, that can happen. And we tell you this but you just repeat that you tried all the tips. You aren't listening.
Your replies indicate you aren't actually reading what people are saying to you but doing something else that isn't actually going to test what people are telling you to test.
I suspect the root issue is you are just used to a non-sealing earbud sound; these all have severely rolled-off sub-bass but many have quite bloated mid-bass levels, and warmer, fuller lower mids. So if you are used to this richer fuller sound, the Chu might sound bass light and thin. But this is how basically any "correct" sounding transducer is going to sound, it's the earbud with the mid-bass/lower-mid boost that is colouring the sound here.
I have quite a few earbuds as well as IEMs, and I have earbuds that are exactly like this, I know how they tend to sound with the physical limitations. And I could understand this, if you are used to this big mid-bass warm lower-mids bloat with rolled-off sub-bass, The Chu is more sub-bass focused with it coming down in the mid-bass and lower mids and that could sound thin or lacking in bass comparatively. See this graph, the Chu is much more "correct" here and has more sub-bass. But the FF3 does sound much warmer, fuller and richer, although to me, also bloated and unnaturally full and rich.