Hi, this is my first post on head-fi. I have tested the L500 and L700 first at the recent Fujiya Avic headphone festival in Nakano in October, and then again yesterday at Yodobashi Camera in Shinjuku. When I first tried the L700 at the headphone festival my immediate thoughts were they nailed the tone, it doesn't have the grating treble of the SR-009 and isn't darkish like the SR-007. It sounded just right. I then switched to the L500 and thought that it sounded muddy in comparison. I know, quite a statement to say about Stax but these were my initial impressions. I was testing the L500 and L700 on the SRM-353X and the SRM-006tA.
Currently I run a 007 Mk2 off the SRM-007tA, female vocals are stunning. I spent quite a bit of time at Yodobashi testing the L700, L500 and SR-507. Firstly, it's obvious after testing that the L700 is a very high end headphone, it's voiced well to the 353X and is satisfying but does sound a little thin. The L700 and the SRM-007tA do not sound good together, there's just no synergy and the music sounds lifeless with no body or grip.
The L500 sounds good with both the SRM-353X and SRM-007tA, however it's a very noticeable step down in terms of tone and resolution. After trying the L700, it would be hard to purchase the L500 knowing the L700 just needs the right amplification. I also tested the 507 and will say it's on par with the L500, the main difference is the width of the soundstage, the L500 has a wider soundstage with a more balanced sound and less treble. My view is the L700 would be a no brainer with the right amplification.