Flash audio in Safari 11 plays through different output

UPDATE:

I have a program installed on my computer called "Boom 3D" (v 1.1) which is an audio output enhancer. Essentially it creates a new audio output option called "Boom Audio" when the application is running (Img 1).

Oddly though, this output option is NOT available under the volume menubar item list (Img 2).

When I quit the Boom 3D application, select my desired headphones (speakers) output, then restarted Safari, audio playback worked on all websites, even when I restarted the Boom 3D application. I'm sure however that if I were to restart my computer, the system audio output selection would get screwed again.

Later I will test this out on my laptop as well (also running High Sierra, Safari 11, & Boom 3D v1.1) & will repost the results.

I doubt that the issue has to do with the Boom 3D application as I doubt that we all are coincidentally using the same application. But, this does point to a system or safari software bug that causes Safari to not recognize any preselected audio output -- thus not knowing where to send audio -- until the desired output is reselected from the Sound System Prefs pane. Again, I'm going to keep playing with it on my systems to see if the issue and "fix" are reproducible.

Hi,

You are not the only one!

This appears to be a bug and it is affecting a number of people, including me.

A temporary fix I have found is to go to Safari / Preferences / Privacy / Manage Website Data and use the Remove button. But the problem comes back.

You may also try the Safari dropdown menu and Clear History or in Safari / Preferences / Privacy / check the Always Block box.

Hi,

You may not have seen the edit I added to my post.

You may also try the Safari dropdown menu and Clear History or in Safari / Preferences / Privacy / check the Always Block box.

Try those as well. You may also need to restart Safari after the changes.

Also seeing different audio behaviours since installing Safari 11 (just with Flash I think, not HTML5 audio).

E.g. audio being sent to the wrong output when using Helium (2.0), and videos on bbc.co.uk (bbc.com works as before though).

Hopefully just needs a Flash update to fix.

I'm having this problem in High Sierra 10.13 on both my iMac & MacBookPro. All sites effected. No issues in Chrome.

This bug renders Safari useless for video - unless you're watching a silent movie.

Hmm... maybe something Flash was fixed in the background (i.e. I didn't change/delete/install etc.), or this behaviour is just plain inconsistent, but audio is working as it should in Safari/Dashboard/Helium today.

Thanks for the heads up!

Mine is working properly now as well. I hadn't been using the website concerned for a while because it was a big pain but on seeing your post tried it. No need to fiddle around any more. Let's hope it's the same for everyone else.

I have the same problem on my iMac. SMC reset cured the problem until the replay is paused, then the audio reverts to the internal speakers even though the USB DAC output is selected.