Hello all,
Recent SE846 owner here. Here are my quick notes:
Usage and music - got this strictly for portable and "fun" use as I fly 100K+ miles per year within US. Spotify 320kps and listen to Jazz, Pop, Acoustic, New Age (until I fall asleep anyway).
Eartips - I use Klipsch large clear oval silicons. They fit well and most comfortable for me. Tried the small Shure olives and caused discomfort after a couple hours. SQ is same for both. I hate foam.
Filter - White, but may go back to blue a soon as my new cables arrive.
Amp - JDS Labs C5, no bass boost needed for my tastes. Tried medium boost (+6db) and I felt like I was in a club, but mids and highs stayed nice and clean.
Cable - OEM, but will be getting custom shortly.
Sound - when pairing these with amps that have 4-10 ohm output (iPhone, Macbook, FIIO E09K), I hear boomy, loose bass which prompted me to get the JDS Amp rated at 0.62 ohm output. With the JDS amp, bass is now nice and tight, highs more airy. Natalie Imbruglia's (who has yet to answer my marriage proposal) "Torn", sounded wonderful.
I asked Shure customer support if adding an impedance adapter in the range of 50-75 ohm would do anything to the crossover frequencies and the technician said it would not be a problem as far as the crossovers go, but depending on the amp, may color the sound slightly. I have a Sony PHA-2 (for my desktop and Beyer T5P) on the way so will definitely listen to with and without an impedance adapter just out of curiosity.
Overall, very happy with these IEMs and I found all the prior comments on this thread extremely useful in deciding on these. Anyone still looking for an amp or amp/dac should take a good look at JDS Labs.