Can't hear sound for embedded YouTube on iPhone

Here’s a new puzzler. My app has some embedded YouTube players and mp3 players. The files are loading and playing but on iPhones, the audio is muted if the ringer is muted.

I’m using several ways to embed the media:

On one form I use a Multimedia HTMLview control and put an HTML5 < audio > tag inside, pointing to an mp3 on my server

On another form I use the Finance & Social Media YouTube control and a Multimedia Audio control

On another form I use a Multimedia HTMLview control and use the YouTube embed HTML to show a playlist.

So I’m doing this a few different ways. They all work in the browser, they work on Android, they all work on an iPad tablet. But on an iPhone that has a mute ringer switch on the side, you don’t hear anything unless the ringer is unmuted. On that phone, I can play YouTube videos in the YouTube app, facebook, Safari…just about anywhere I can hear the video even if the ringer switch is on mute. But in my app, everything is silent until I unmute the ringer. I don’t want to include a tooltip to tell the user to unmute their ringer, this should work without them needing to do that.

Any ideas?

To maybe clarify the problem: My audio and video have sound unless “Silent Mode” is turned on on the iOS device. At first this may sound like this is how it should work until you consider that the YouTube app, Facebook and plenty of other apps are still audible when in “Silent Mode”. Silent Mode seems to indicate that the phone’s ringer is muted, not necessarily the apps. Why does “Silent Mode” mute my app but not other apps? (on iOS)

This doesn’t sound like something AppStudio would have any control of.