Netflix has integrated high-end audio technology into Stranger Things to enhance the viewing experience:

While it is tempting to search for "free download" links, the only official and secure way to download Stranger Things Season 1 with dual audio is through Official Streaming & Download As a Netflix original, Stranger Things

Dual audio refers to a feature that allows viewers to switch between two audio tracks, typically in different languages. In the case of Stranger Things Season 1, the dual audio feature might be available in English and another language, such as Hindi, Spanish, or French.