My piece certianly isn't reliant on audio; my time has gone into making it as visually appealing as possible. It begins visually and concludes visually, the audio just enhances what's on-screen.
Many topics uncover professional material being delivered audiably through a QR code.
"Innovative QR Codes Deliver Newspaper Content with Audio"
“We took QR codes beyond advertising and now deliver full audio versions of articles via QR codes directly from the headlines,”http://www.editorandpublisher.com/ASection/Article/Innovative-QR-Codes-Deliver-Newspaper-Content-with-Audio--Video-on-Mobile-Web
"...different QR codes to lead to different content"
A band can put different QR codes to lead to different content -- one code for video, another for audio, and another to add a concert to the user's calendar.http://www.billboard.biz/bbbiz/industry/digital-and-mobile/business-matters-americans-getting-into-1005315862.story
"QR codes bridge the gap between offline and online media"
One of them, a version of Around the World in 80 Days, uses QR codes to provide readers access to the audio versions of the book chapters and to Google Maps.http://ss.seamlesssocial.com/tools/7-benefits-of-qr-codes-for-content-marketing-or-inbound-marketing
Notes
Before the advertisement begins, I've decided to flash a clear icon of a speaker up on the users display. This should remind them, if their device's silenced, to activate their sound. The idea is to make it minimal and as unobtrusive as possible.