Sound-Field

Connect your iPhones in the room. Pick a song on the host and every device plays it at once — even old phones or a friend's, just by installing the app.

Use the iPhones you already have as speakers.

NOTES

• Around 8 devices is a practical guideline. More devices are more sensitive to your Wi-Fi conditions
• Streaming tracks from Apple Music and similar services cannot be played because of DRM. Use audio files stored on your device
• No internet connection is required and no audio ever leaves your devices

WHAT IT DOES

• Pick a song on one device and every connected device plays it at the same moment
• Old devices, and devices belonging to friends or family, can join too — just install the app. Only the host needs to have the audio file
• Adjust volume and a 5-band equalizer per device, controlled from the host
• Import audio files from your iPhone and send them to the other devices automatically
• If a call or notification cuts the music off, playback picks up where it stopped
• Works on a single device too, as a music player with an equalizer

HOW IT STAYS IN TIME Devices agree on a shared clock and exchange only "play at this exact moment". Audio is never streamed between devices, so a shaky signal does not interrupt playback. Measured offset between devices is under one millisecond.

HOW TO USE

1. Set one device as the host and the others as speakers
2. Join the same Wi-Fi, or simply leave Wi-Fi switched on
3. Pick a song on the host and press play
4. Tap a speaker card to shape that device's sound