Linux Music / Audio Program Idea

OK,

I have had this idea kicking around in my head for a good number of years now and have spoken about it with various people from time to time.

I decided to document it here to see if it might help get things moving.

I am speaking from ignorance so let me know if I cam out in left field with this.

The idea is to play a note on the PC or on an external source. If from the external source, determine the frequency of the note.

Display the note as a coloured line in the centre of the display window. (Time on the horizontal axis, Frequency on the vertical axis.

Let a person try to sing the note.

If the note is played above then feed the played version in on the left channel and the sung version in on the right if needed.

determine the frequency of the note sung and display the note as a different coloured line in the display window. Above the centre line if the sung note is higher in frequency, below if lower.

I think the thing to do would be to have the colour change to a lighter version of the centre colour the higher the sung note gets and to a darker version of the centre colour the lower the sung note gets. when the notes match, the lines and colours will meet and match.

Is that clear?

Does something exist in the Free Software world that can do this now?

Do the parts already exist from which such an app can be cobbled together easily and quickly?

Thoughts?

Edit: I think it might be a worthwhile idea to have each target note be represented by a different base colour.

all the best,

drew