Turn the music down and the bass can seem to disappear. That does not automatically mean your IEMs need more power.
Your ears hear the balance differently
At low listening levels, deep bass generally becomes less noticeable beside the midrange. The earphone may still be producing it; it just does not sound as full.
Check the ear tips first
Reseat both earphones and replay the same passage. If the bass returns, the seal was part of the problem. Try a compatible tip that stays comfortable and secure. Smaller is not always better: a tip that leaks can lose bass.
A little EQ may be enough
If the fit is good, try a small bass boost. Reduce the EQ preamp to leave room for that boost and avoid clipping. There is no single setting that works for every earphone and listening level.
You do not need to keep turning the volume up to make the music fuller. A quiet-listening EQ preset may suit you better.
For a community IEM project, tell us when you listen. Quiet evening listening is a useful design requirement—not just a request for “more bass.”
Read next: Why bass EQ can distort · Explore IEM co-creation
Background: ISO 226 equal-loudness contours. These describe hearing under specified conditions, not a personal IEM EQ curve.