Sync Multiple iPhones Together To Create One Giant Speaker
Seedio connects iOS devices together to create one large sound with all devices playing the same song at the same time.
Seedio is an app that amplifies the sound on an iPhone without any additional attachments. The iOS app connects multiple devices to “create one perfectly synchronized loudspeaker.” The app plays media from the Music Library or YouTube and broadcasts it over Wi-Fi to sync group playback.
The app also allows you to play music seeded by other Seedio users and search for tracks on iTunes. Seedio is great for outdoor parties and playing music on the go without the need to lug around heavy equipment. It's currently available in the Apple Store for $2.99 and can sync up to 150 iOS devices at one time.