The MoodBlocks app requires you to specify one Sonos speaker as your "start speaker." When you tap a MoodBlock, music will begin playing on this speaker and any speakers currently grouped with it.
Add or remove speakers from your start speaker while music is playing
On the play screen, located next to the volume bar, select the "speaker" icon. Your start speaker will be grayed out at the top. You can add or remove any other speaker from the group. You can also make changes using the Sonos app.
Switch to a different start speaker
At any time, you can change your start speaker. Once you have done this, all your MoodBlocks will begin playing on the newly selected start speaker, along with any speaker currently grouped with it (see above). To switch your start speaker:
On the play screen, click the "speaker" icon located next to the volume bar. Your start speaker will be grayed out at the top. Click on it, and a gray popup screen will appear. Select your new "start speaker." You can modify this setting at any time in the future.