Hi there,
I haven't heard the Noble 5. It's a direct carry-over from the Heir 5, the only one of the line to do so without revision (the 5 was the last to be developed, iirc). It's said to be dark. I have a feeling it matched up with the Heir 8.A rather than the Noble 8.C, which has an adjustment to the treble.
For the Noble 4C--the custom version which I have, I can say the bass goes deep on my set, just there's not a lot of it. But there are two bass drivers. It seems to respond fine to eq. to my ears. You can see LFF's famous "perfect water drop" review of the Frogbeats C4 which talks about the great bass extension. Thanks to some awesome there are some graphs of the universal fit Noble 4, the same earphone here, on CS, which do show some bass roll-off. Noble's own internal-use-only graph doesn't show that, interestingly, nor do my ears for the custom version. The Heir 4.a, Frogbeats C4 and Noble 4C have the same drivers and bass tuning, with the Noble 4C having a tuning correction, completely removing a dip which the other two have in the lower treble, I believe it was.
Here's my review of the Noble 4C
http://www.head-fi.org/t/690751/review-noble-audio-4c-4-driver-3-way-custom-fit-in-ear-monitorAnd here's my Noble Kaiser 10 review.
http://www.head-fi.org/t/685225/review-noble-audio-kaiser-10-10-driver-custom-fit-in-ear-monitorI still like the Noble 6. I'd like just a little more sub-bass to it and then it'd have been almost perfect for me (if my memory of it is at all accurate).
