I was wondering about etymotice IEM's. Especially some of the differences between er6i and er4 s (or p i'm not really sure what the "s" or "p" means as well)

I just got my ATH-AD700's and because of their dark purple color i associated it with Covenant technology from Halo. Therefore i nicknamed my headphones "Truth and Reconcilliation". (A Covenant warship from the first Halo) It would be interesting to know others nicknames for their cans

i ordered the audio-technica ATH-AD700's. I am a n00b, low-level audiophile and have a few questions. 1. do i need an amp? (if so i want to be able to carry it around (portable)) 2. And if so, what should i look at? 3. if not, ignore #2