Pjotr Iljitsch TSCHAIKOWSKY

Пиковая дама (Pique Dame)

Szene 2 № 7 Duett Liza und Polina

Уж вечер... облаков померкнули края 

Es ist Abend... die Wolken verziehen sich

Full length version with sampled mezzo sopranos (vocalises). If you purchase the playback, you will of course get tracks without vocals.

And here is an excerpt of the purely instrumetal backing track: