Frank

I just sing fine harmonies with many people I am told.

I call it a blend of voices, not a balance. I do my best to blend with another singer's voice. My voice works fine into my 50's. No harm done to my voice blending with others professionally for about 40 years.

I think trying to find the distinction that you talk about is way too over analytical.

I have never been told my voice balances well with someone else. The sound of fine harmony produces a fine blend of voices.