---
title: "Silent Disco App on Every Phone, in Sync | sync.video"
description: "Run a silent disco or silent cinema on guests’ own phones and headphones: one room code, the same beat in every ear, a delay per phone for Bluetooth. Free."
url: https://sync.video/silent-disco
---

1. [Home](https://sync.video/)
2. [Sync player](https://sync.video/sync-player)
3. Silent disco

Free · runs in your browser

# A silent disco on everyone’s own phone

Guests open the same file on their phones, join with a code and listen through their own headphones, with every ear hearing the same beat and each phone corrected for its headphones’ delay.

For a silent disco without hiring headphones and transmitters, give every guest the same audio or video file, have them open it on this page on their phone, and join one room with a code. Their phones then play in sync through their own headphones, and the host starts, pauses and skips for everyone.

The hard part of a phone-based silent disco is not the network but the headphones: wireless earbuds delay the sound by a different amount on every model, so a room of phones that are perfectly in step can still sound smeared. That’s why this version puts each phone’s **Output delay** up front, with a quick [delay test](https://sync.video/audio-delay-test) to measure it.

The same set-up suits a silent cinema in a park, a quiet dance or fitness class, or a guided museum tour. It runs on the [sync player](https://sync.video/sync-player) with sound switched on for every device.

Where the delay comes from: the picture goes straight to the screen, while the sound passes through decoding, a soundbar or receiver, and a Bluetooth link, each adding milliseconds.

## How to run a silent disco with phones

1. ### Share the mix
Send guests the same file before the event: a long DJ mix as an audio-only video, or a film for a silent cinema. Everyone needs the identical file.
2. ### Start the room
On the host phone, drop the file onto **Drop the video to play in sync**, press **Start a room**, keep **Sound** on **Every device** and **Who controls playback** on **Only me**, then press **Create room**.
3. ### Guests join
Show the QR code, or read out the code for **Join a room**. Each guest chooses their copy with **Open your copy of the video** and puts their headphones on.
4. ### Correct each phone’s headphones
Run the host’s **Flash and beep test** (C). Anyone who hears the beep late moves their **Output delay** (or \[ and \]) until it matches the flash, then presses **Remember this delay on this device**.
5. ### Start the party
Press **Play for everyone**. Use **Pause for everyone** for announcements and **Start again for everyone** for an encore.

## Why headphones are the real challenge

Inside the phone, the sync is tight: every phone plays the same moment of the file to within a few milliseconds on a good Wi-Fi network. But after the phone, wired headphones add almost nothing, while Bluetooth earbuds typically add from about a tenth of a second to a third of a second, depending on the model and the codec they use. Two friends dancing next to each other, one wired and one wireless, can be a beat apart.

Each phone’s **Output delay** makes up for that by playing slightly ahead. **Add the delay this browser reports** fills in what the phone itself knows about its sound path; for Bluetooth that is often only part of the story, so a quick listen during the **Flash and beep test** finishes the job.

### Measure once, remember it

Guests who measure their phone with the [audio delay test](https://sync.video/audio-delay-test) and press **Use this offset on this device** there, or **Remember this delay on this device** in the room, keep that figure on their phone for next time.

## Planning the event

* **Wi-Fi.** One strong network for everyone gives the tightest sync. Guests on mobile data still work, with a little more correcting going on.
* **Battery.** Music playback with the screen off is gentle, but ask guests to arrive charged and keep a power bank or two handy.
* **Screens off.** Phones can lock while playing in many browsers, but some pause media when locked; ask guests to keep the page open and lower their brightness instead.
* **Size.** A room holds up to 50 phones. For a bigger crowd, run a second room with its own code from a second host phone and start both together with **At a set time**.
* **Channels.** A classic silent disco has several DJs on different channels; here, each channel is its own room with its own file and code.

## Silent cinema and quiet classes

For a silent cinema, project the film from a laptop that hosts the room with sound, and have the audience join with the same film file and listen on their own headphones. Set the projector laptop’s **Sound** to **Every device** so its picture and the audience’s ears share one clock, and keep the projector’s own speakers off.

Fitness and dance teachers can use the same trick in a shared space: the class hears the track in their headphones and the teacher pauses for everyone between sets, without disturbing the room next door.

## Silent disco questions

### Do guests need to install an app?

No. They open the page in their phone’s browser, choose the file and join with the code. There’s no account and nothing to install.

### Can we use Spotify or another music service?

No. Music services don’t let other websites play or control their streams. Every guest needs the same file on their phone, such as a mix you have the rights to share.

### Why does my friend hear the music slightly before me?

Your headphones probably add more delay than theirs, which is normal with Bluetooth. Move your **Output delay** up until the beat matches, during the host’s **Flash and beep test** or by listening to each other.

### Does it work with wired headphones?

Yes, and they need little or no correction, which makes wired headphones the easiest choice for a tight sound.

### Can the music be an audio file rather than a video?

The player opens video files, so put the mix in an MP4 or similar with a still picture. Every phone must have the identical file.

### How long can a room last?

Up to 12 hours, which covers most events. If the host phone drops out, it can rejoin the same room with the same code, so keep it charged and on the Wi-Fi.

## More in sync player

* [ Play a video in sync on several devices A room code, a shared clock and every screen playing the same frame at the same moment. ](https://sync.video/sync-player)
* [ Make a video wall from phones, tablets or TVs One picture split over a grid of screens, with gaps for bezels and every tile in step. ](https://sync.video/video-wall)
* [ Host a watch party with your own files Friends in different homes, one film, the same moment on every screen. ](https://sync.video/watch-party)
* [ Test your audio delay A flash and beep, a microphone chirp or tapping: a latency figure in milliseconds. ](https://sync.video/audio-delay-test)
* [ Sync audio and video online Drop one video to fix its delay, or several files to line them up by their sound. ](https://sync.video/)