A person who can't play an instrument well but "hears" a song and sound in his head starts using a loopy program and searches for hours for the sounds and instruments to vibrate the air with the song in his head, often agonizing on his inability to find the right sound.
Spends countless more hours adding, arranging, reading about mixing, then mixing the song.
He might be a technician. He might be an engineer. He might be an artist painting a soundscape.
If the sounds are even a little bit musical, he might be a musician.