My personal favorite iem is the shallow insertion Stax SR-002 which are driven nicely by their special Stax portable amplifier via it's audio input jack (runs off 2 AA rechargeable batteries1.5V 3.7Amp 3,000 mWH or wall adapter of 120V 6W AC to DC 4.6V 0.4 Amp).
On my hour plus long walks away from noisy traffic/wind they are, to me, decisively much more enjoyable sounding when streaming my preferred genre of music (jazz) from my cell phone's audio out jack than any of my other iems (etymotic, planar, or dynamic). Their nozzle is actually oval and I've noticed it's alignment with the opening of the ear canal adds a slight improvement. (The interior is protected from debris by a fixed plastic covering; being shallow insertion minimal ear wax deposits.)
Pictured below they have an external isolation housing which wouldn't be necessary for indoor listening; it's profile makes the Stax SR-002 unstable for staying in place jogging/dancing/working-out. As for bass: these are electrostatic headphones and less suitable for certain bass slamming songs.
Indoors I've also run these iems off an amplifier's headphone out jack with an adapter cable into the input jack of the Stax portable adapter. With the amplifier itself connected to a graphic equalizer that was receiving the original audio signal that allowed different frequency EQ-ing of what heard from the Stax SR-002
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