all of the following are parts of what a audio technician does except

voices
sound effects
background music
hire actors

"Hire actors" isn't what an audio technician does, because it's not audio related. Also, it's more like what the director does.

To figure out which of the given options is not part of an audio technician's role, let's go through each choice and examine their relevance to audio technicians:

1. Voices: Audio technicians are indeed involved in working with voices. They handle tasks such as setting up microphones, adjusting audio levels, and ensuring clear and balanced recordings of voices.

2. Sound effects: Audio technicians are responsible for creating or sourcing sound effects, editing them, and incorporating them into various media productions like films, commercials, or video games.

3. Background music: Audio technicians also work with background music. They select appropriate music tracks, sync them with the visuals, and mix them into the final product.

4. Hire actors: Hiring actors is not typically part of an audio technician's job. Although they work with voices, their primary focus is on technical aspects such as recording, editing, and mixing. Hiring actors typically falls under the responsibilities of producers, directors, or casting directors.

Based on the analysis, the option "hire actors" is the correct answer as it does not align with the usual duties of an audio technician.