great review but two minor points: would love to have had you include some big symphonies as your musical test, only because I find the Sleek properly ported treble and bass often outperformed the Triples, esp. in big Mahler symphonies--instruments with choir, that kinda thing--or Bach's B Minor Mass. Minor point, though.
Also be aware that I had two Sleeks returned to soundearphones, Michael told me to contact sleek, which I did, and Json very graciously took back the second faulty pair and told me they had since brought all manufacturing "in house" rather than relying on overseas' manufacturing. Point is, those who have some faulty parts may have those Sleeks that were NOt made here but overseas somewhere. A factor worth investigating.
Otherwise, great work. hate to nit-pick but some of us on here Do listen to classical works as well as other musical varieties