January 31, 2014 at 3:13 pm

How To: Play One Sound from Many Devices (Flashmobs, Home Audio, Pranks, More)

speakerblastWhen Ryan Spahn and his friends watched the viral video “The Harlem Shake,” they had a thought: What if a bunch of people dancing together could just whip out their smartphones and get them all to play the same song at the same time?

They built the answer to that question: SpeakerBlast, a simple web app that lets one person cue up a sound (this could be a sound, a speech, or a song, either from their computer or somewhere else on the web), and then distribute a URL to other people. When the person in charge of that particular SpeakerBlast hits the Play button, the song or other sound emanates simultaneously from all of those devices — any computer with the Chrome browser, and any iOS or Android smartphone.

The implications of this technology are manifold and amusing. You could throw a dance party in a field — no generator required. You could make a very loud burp sound in a school gymnasium. You could crowdsource a dance party airhorn. You could… well, you get the idea.

If you just want to find out how to do this, skip down to the bottom, but here’s the scoop from Spahn on how this thing works and where it came from. Our first question: How does this free web app manage to keep the audio in sync? In our testing, it appeared to sync up really well between multiple devices.

“As for how it works and plays audio in sync, just think of a bunch of alarm clocks going off at the exact same time,” Spahn explained to Evolver.fm. “We are fans of alarm clock technology, as our first app/start-up is something called Sleep.fm: The Social Alarm Clock.  After building Sleep.fm’s mobile iOS web app in Jan. 2013, we realized we could use it’s codebase to create SpeakerBlast…

“A month after working on SpeakerBlast, we witnessed Samsung introduce this feature into the S4, under their ‘Group Play,’ moniker, though their implementation is limited to those only with Samsung phones. SpeakerBlast is web-based and available on iOS and any device running the latest version of Chrome.”

And so was born SpeakerBlast. Here’s how to set one up for your next party, prank, or listening party:

1. Go to SpeakerBlast.com and click “Create A Blast”:


2. Upload your own sound file, or use SpeakerBlast’s search function:

3. In our experience, you’ll need to scroll down past the irrelevant “recommended tracks” to get to the ones SpeakerBlast returns from Ex.fm’s catalog of blog-based music:

4. SpeakerBlast will generate a URL:

5. Share that URL to the rest of your danceparty, crew of pranksters, or your own devices around your home. That URL will need to be entered in the browsers on those devices, after which users are offered the ability to “check in”:

speakerblast check in

6. Once at least one other person has checked in, the organizer simply hits the play button, in order to make the song or sound play on all the checked-in devices:


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  • Ryan Spahn


    Thanks so much for the nice write up and cool you thought of use we hadn’t – pranks.

    Someone recently mentioned it could be used for police diversions.

    thanks again!