With JBL PartyBoost, you can connect multiple JBL speakers to each other. You can do this via the JBL Portable app. When they're connected, they all play the same music at the same time. This way, you have a louder sound. When you connect 2 speakers to each other, you make a stereo pair. Place them both on other sides of the room, so you hear more spatial sound. This way, it's like the music is playing live.