ALWAYS have audio playing while pedaling solo (especially on rural roads.)
NEVER use audio when pedaling with others.
I have a
Amazon.com: Cambridge SoundWorks OontZ Angle Enhanced Edition Ultra Portable Wireless Bluetooth Speaker attached to the handlebars with a couple strips of Velcro and it works like a charm.
Like many, I disdain the use of ear buds by most anyone participating in a public activity.