which tuning scale is optimal when recording an instrument for a sample library, Equal Tempered? I know it's the standard, but pure E.T. tuned instruments sound just a bit flat to me. On the contrary, if I tune an instrument (or it's samples) to fit with some reference live recording, it usually sounds better and more natural (even the instrument playing alone with this new tuning), but I suppose it's less universal (due to the fact - different key of the song=usually different optimal tuning).

I also noticed that only relatively few percents of live recordings are "compatible" with E.T. tuning. Moreover, I've found the tuning scale that seems to be compatible with a lot of live or studio recordings (soundtracks, classical music rec.) and sounds nice. But again - propably it isn't the standard. In my subjective opinion - and I might be wrong - E.T. tuning fits to about 5-10 % of recorded music (for example Dies Irae from Mozart's Requiem, but other movements not.. Beatles - Yesterday, but a lot of other songs not, etc.). In theory - it's not a problem to find another "one" tune scale, compatible with much more recorded music than E.T. and subjectively nicer sound. However I'm not sure it's a good idea to use it for a sample library. I'd appreciate any info on this topic, thanks.