People who search for a bass voice generator usually want one of two things: a very low speaking voice for a video, or a bass singer. This tool does the first. It reads your text in a deep speaking voice. It doesn't sing, so it won't perform the bass line in a song.
In music, bass is the lowest male voice type, singing roughly from E2 to E4, or 82 to 330 Hz. Speaking voices sit at the low end of that picture: adult men usually talk at about 85 to 155 Hz, and the voices people call deep sit near the bottom of that band. The preset aims for that low, resonant zone, and the Deep effect pushes it a few semitones further.
Curious where your own voice lands? The free deep voice test measures your speaking pitch in Hz, and the deep voice changer lowers a recording of your real voice right in the browser, with no credits needed. Want the full cinematic treatment instead? The movie trailer voice generator adds dramatic pauses, and every other style is in the AI voice generators hub.