Alright, time for my write up on the L9 vs L3 (Day 1):
About me: I like bass guitar... a lot, not a treble head but I like my cymbals to be a little hot with splash and shimmer. Typically listen to Female vocals.
While these IEMs share the same series name, they can't be any more different. L3 can be described as a proper balanced IEM tuned similarly to TOTL IEMs with a small mid-bass bump and presents the music in a very natural way, a very laid-back IEM. The L9 shares about... none of those similarities. The vocals are much more intimate and thick in comparison, the cymbals splash and shimmer brilliantly on the L9s, the Sub-Bass rumbles hard, everything is thicker and denser for a lack of a better explanation, in some ways more fatiguing that the L3.
Treble:
The L9 has spectacular treble performance, cymbals sound full with plenty of air and shimmer. L3 can sound washed in some cases comparatively but they never sound veiled as I find in the Solaris. It's safe, for better or for worse. This is more of a testament to the L9 rather than a shot at the L3.
Mids:
This is more of a preference between the two. The L9 has very intimate forward mids, L3 has a more natural presentation of their mids being slightly recessed, not thin but no where as thick as the L9s. It's a toss up whether of not you prefer intimate or more natural mids.
Bass:
Now this is where the tables turn, I prefer the low-end on the L3 more than the L9. With the thick forward mids in the L9, a lot of the time, it blurs a bit with the bass guitar. This isn't the case with the L3 where the bass guitar is clearly separated. Slaps on the bass guitar sounds more clear on the L3 than the L9, with the texture on the bass guitar being more well defined on the L3 than the L9 which can get a bit muddy, the bass is punchier on the L3 and not as boomy as the L9.
Soundstage:
L3 is noticeably wider than the L9, with L9 noticeably having more depth.
Conclusion:
It feels like these IEMs were meant to compliment each other. The natural and light taste of the L3 is always a safe bet and edible, while the rich and thick taste of the L9 can overwhelm some people and will appeal to less people but can be seen as a treat for people trying to break the norm. With the weight of the both buds of the L3 clocking in at 7 grams total compounded with the laid-back tuning, it's great if you are just going about your day. If there was a way I can get the mids and treble of the L9, and the low-end of the L3, I don't think I would want for anything else in an IEM.
It depends on how you like your pancakes, some like it with just smooth melted butter while some like it topped with rich and thick maple syrup.