Well, well......today I just learnt there is an alto clef and a new instrument to me! You're a star and I hope the concert goes well. May I ask what the music is please so I can listen and see if its on the list in Wikipedia......talking of which, are you listed there as a player?
Oh. Final question, what other instruments do you regularly perform with and which is your favourite and / or most proficient please?
Great post :-)
Alto is primarily for the Viola, the viola d'amore uses a great range of clefs depending on the music... including the Grand Staff! In my sort of music, I play from original scores generally... there are many many many clef types...
As for recordings of the piece "Rittrato dell'amore" by Couperin, there aren't any YouTube recordings that would whole heartedly recommend. This one (from a playlist that has the whole 8 or so movements) is the best that I could find, but I find it too ponderous...
I normally play in the Historical Style (also known as Early Music) on Violin, Viola and Viola d'amore. I'm decently proficient on all of them (well, at least people don't throw hard things at me when I play...), touring around the world with various groups and ensembles... I don't think I'm listed on Wikipedia!