Choose which speakers to use in Podcasts on Mac
Besides listening to Podcasts with your computer’s built-in speakers, you can listen to Podcasts through any of the following:
Speakers connected to your computer and a power source
Remote speakers connected to an AirPort Express
An AirPlay, AirPlay 2-enabled device, including HomePod or network speakers (for example, Apple TV played through TV speakers)
Bluetooth devices, including wireless headphones such as AirPods
For information about connecting speakers to your computer or network, see the documentation that came with the speakers.
Choose which speakers to use
Use external speakers: Connect the speakers to your computer. Audio plays through them and mutes the computer’s built-in speakers.
Use speakers connected to an AirPort Express, Apple TV, or another AirPlay-enabled device: In the Podcasts app
on your Mac, click the AirPlay button 
at the top of the Podcasts window, then select the checkbox next to the speakers you want to use.You can select more than one checkbox to play audio through multiple sources.
Set a maximum volume for speakers
In the Podcasts app
on your Mac, click the AirPlay button at the top of the Podcasts window, then use the volume slider next to the speakers.
If you can’t choose your remote speakers
If you’re using speakers connected to an AirPort Express: Make sure your AirPort Express is properly plugged into a working power outlet and your remote speakers are properly connected to your AirPort Express.
If you’re using speakers connected via a wireless network: Make sure your computer is in range of your wireless network and your AirPort Express, Apple TV, or other AirPlay-enabled device is joined to the network and is active. You can use the Wi-Fi status icon
in the menu bar to make sure your network is selected (has a checkmark next to it).If you’re using Apple TV: Make sure your Apple TV is turned on and connected to your Wi-Fi network. See Stream content using AirPlay with Apple TV.
If you’re using HomePod: Make sure your HomePod is turned on and connected to your Wi-Fi network. See the Apple Support article If HomePod isn’t responding.
If you still can’t choose your remote speakers, or need more information about setting up your AirPort Express, Apple TV, or AirPlay-enabled device, see the documentation that came with it or visit the AirPort Support website.
If there’s a problem with an AirPlay device
If the AirPlay button changes 
, there’s a problem with an AirPlay device.
In the Podcasts app
on your Mac, click the AirPlay button at the top of the Podcasts window to open the AirPlay menu.Check the icon next to the device.
: You need to enter a password to connect to the speaker.
: You’ve selected a device but haven’t entered its password.If you see a dash (–) next to the device, click it to attempt to reconnect the device.