As mentioned emotion and feelings is often used when describing though these audio descriptions are most often used in pieces where the audio is used with intention which makes it easier. For example to create tension in a film scene or to indicate mood when scoring a scene of loss etc

Audio used in context if that makes sense

Audio used solely for listening purposes becomes more difficult I guess but I’d think about what feelings and emotions it creates and what you visualise when listening. Use terms like dark and bright, slow and fast, calm and aggressive, rough and smooth, subtle and intense etc