Just thinking about the Etymotic er-4B versus er-4p, I went out and bought a 30-ohm impedance adaptor for a few bucks and a laugh.
What should I expect in terms of sound changes, if any for:
1. iems with a single dynamic driver?
2. iems with a single BA (like the er-4)?
3. iems with multiple BAs or BA-dynamic hybrids?