I use comply tips and get a great seal and comfortable fit. You might be using too small of tips if these keep falling out.
Holy Lord... After disassembling the tips to clean everything, the bass suddenly became much more intense. So much, that I had to open the valves again. Apparently I initially pushed the tips too far on the P1. Because now they stick out visibly further. As the P1 now sounds, there can be no question of little Bass. Can someone confirm that the distance is correct?
I am at a loss. what happened to my P1 at once? Suddenly there is a lot of bass, as well as high tone present... I still can not believe how fundamentally the sound has changed, in that the tips now about 1-2mm further out. I have to use completely different equalizer settings!
I 2nd the recommendation of fat foam tips. I just got a set of Comply Comfort 500. Bass is wonderful. I had a no name set of foams I had tried that indicated a larger seal would improve these, but they have been a bit old. New foam and careful placement in the ear canal let's the planar's sound stage shine. I'm listening to people at the tables talk amongst themselves at the tables, near the stage, from 1960, At The Half Note Cafe, Volume 1, Donald Byrd. I've never heard them distinctly before.
The P1s are indeed power hungry, but not as much as some people in this thread make it out to be. I'm running my P1s from the Cayin N5ii via the balanced output, and my volume interval is within the 50-70/100 range. The bass was surprisingly weighty, I was expecting something anemic but all I got were tight, clean, and bodied bass notes. I'm so fond of the P1s that I haven't touched my UERR for 3 days.
I run my P1s straight from my N5 and QP1r and find both power them comfortably loud enough. Bass hits, but it's v.clean and fast, not flabby or exaggerated at all.
OK, sounds promising. I may try my good old iBasso P4 or Cayin C5. Either of these is more than capable of driving HE400i...
I have read that they are not a particularly good match for the Mojo. I generally use portable cans with that, in any case (FAW recabled T51p).