I wanted to compose a song starting out by using only 4 voices in the traditional SATB way and get a mockup for the song I am producing. I am the singer and producer and just want to get a mockup of the voice leading involved so this score is just for compositional purposes. I have never done this before so I am just trying to apply what I learned in harmony class and trying out different ways of scoring for my own purposes and my own vocal range. All suggesitions are welcome.
The score here has a piano part which is just an accompaniment and not part of the voice leading. The question I have relates the the grand staff. I am a baritone but in the chorus of the song I sing a bit higher and here I decided to use the "alto" part in the arrangement (in red). I use the "tenor" as my vocal part in the rest of the score (not shown). Ranges are not an issue for the other "voices" because they will be instrumental in the arrangment.
So the issue I have is in measure 18 moving from the F3 to the C4 in the next bar. In an ideal voice leading scenario, the alto would stay on Bb but my vocal melody dips all the way to F making a unison with the tenor and both those parts move up in similar motion. my question is:
Is this a problem? If so how to fix it