A word like "visual" but for music and sounds

As superato has indicated, a word for purely sound materials is aural.

In your position, however, I would consider discussing your multimedia or audiovisual approach or strategy (reasoning below).

Depending on what you expect your users to do, a more specialised usage might be interactive media.

Ugly though it is, your audience might also connect well with your media strategy. I have had to accept this: my Ph.D research centred on visual texts, and associated colloquial terminology. You or your boss can best decide whether your expected audience will respond most instinctively to this term.

(These days the term ‘media’ is commonly used to distinguish sound and moving pictures from pure text. It can also refer to static pictorial narrative material—comics, for example.)

You appear to be talking about integrating visual material (moving or static) with sound, in an online presentation. If I understand you correctly, neither the visual nor the aural element would work in your project without the other. If that is so, it seems that you need a term to suggest that integration.

In that case, audiovisual or multimedia are established terms, depending on whether you wish to emphasise the communicative or the technical side of your project.