Re: Pakistani Singers
That IS ‘tuning’ sarab! Basically adjusting the pitch of the sound.
In tuning the instrument one has to make sure ONE CRISP NOTE is played when ONE KEY is pressed or ONE string is stirred.
Also, when one learns how to sing and tunes the voice, one has to make sure one makes sound exactly as ONE note of the instrument at a time.
The person has to adjust and train the voice to match the note/pitch at a time.
You must have heard people doing Aaaaa,… Aaaaaa.
First Aaaaa may be harmonious to C (Saa) and second one to C# (Re) and so forth.
Now if played in a song, then combination of notes can be played. When singer sings, singer then can change pitch and scale periodically to make a song which sounds good to ears.