XE6 is definitely different than Indigo.
XE6 is:
- Much warmer, big bodied sound.
- Much more lower mids presence, which helps contribute to the first point above.
- More dynamic.
- Wider soundstage, sounding quite more open in general, spherical. Indigo’s soundstage is smaller, basically in the head imaging for me, but also very good if you like a more intimate presentation because of the smaller sphere.
- Less “correct“ timbre than Indigo.
- More impactful bass and overall more bassy than Indigo. Indigo is fairly balanced between sub and mid bass, whereas XE6 sounds more mid bass dominant. XE6 bass is more textured, airy, and is of an overall higher quality than Indigo’s bass.
- Midrange is less forward in the mix.
- Treble is more extended and more refined to me than Indigo treble which can be a bit coarse. With that said, I think them Indigo treble tends to have a bit more presence within its tuning when compared with XE6.
In general, these are two differently tuned IEMs.