A truly great DJ, just for a moment, can make a whole room fall in love, because DJ'ing is not about playing a few tunes. It is about generating shared moods; it's about understanding the feelings of a group of people and directing them to a better place. In the hands of a master, the right music can create rituals of spiritual communion that can be the most powerful events in peoples' lives. – Bill Brewster

In electronic music, the beat is everything. As an artist, your goal during a set is simple: take the crowd on a roller-coaster ride of emotions. How do you do this? There are countless mechanical elements, of course, things like the pace of songs and the tension and tempo, but the paramount thing is reading the crowd with as much focus as you can. You need to intuit what they're feeling and thinking, read what hits and what flops, and then fine-tune along the way and in future sets. It's not an easy thing to judge with accuracy: Your best guess at what the crowd is feeling comes in the form of yells, fist pumps, or that all-important but ever-elusive "vibe." Subjective? Sure, but it's all you've got.

But it's what separates a mediocre DJ from a great one: their ability to absorb the crowd and work them. In that last 6 years, we've performed for well over a million people. In front of 100 people and in front of 100,000 people. We're not perfect or the best in the world at, but we've gotten pretty good.

Earlier this year we were hanging out with a friend of ours that told us about a story on Boing Boing where a woman had worn a fitbit during sex. We checked it out and thought it was intriguing. You could see the rising heart rate and the spikes of activity, real data attached to the most natural act any of us know.

What happened next started as an idle joke. "I bet our sets produce an even crazier reaction," someone remarked. Everyone laughed. Then stopped laughing when we all realized that the joke could become a genuine experiment.

The execution was simple: we'd ask a few of our fans to wear heart rate monitors to our sold out show at Vulcan Gas Company in Austin. We'd record the set, capture all the data from the heart rate monitors, and we'd overlay the rhythm patterns on the progression of the recorded set. We played in a purposefully smaller venue that night, so we knew it would be prime to really go off.

To ensure accuracy, we limited the participants to ones who agreed to be sober during the whole set. No alcohol, tobacco, illegal substances, etc. All agreed (though as you'll see, one of them clearly did not comply).

There was no real goal other than to see–outside of clapping or social media reactions–how people really felt and reacted to our music. To see what songs our fans particularly loved. And not just which songs, but which parts of which songs, and which beats in which parts of which songs.

As you can see below, while people's hearts all went along their own paths, there were a few points in the night when everyone's heart rate shot up in unison.

All Heart Rates

Average Heart Rate

6 Biggest Spikes

Zeds Dead — Hadouken

Zeds Dead — Lost You

Zeds Dead — Adrenaline

Dodge and Fuski — Positive Vibe

Zeds Dead & Melodon — Wit Me Dub

DJ SKT — Take Me Away ft. Rae (Andy C Remix)

"Participant 4"

And then we have "participant 4". Ah, participant 4. As much as we'd love to believe our music shot someone's heart rate up to a level described by the American Heart Association as "extremely high intensity", a range where people over 40 may die (180 beats per minute), our interactions with this participant that night made it clear their interpretation of "sober" was quite loose.

When this particular participant stumbled into the green room after the show, it was like a scene out of the walking dead, and immediately obvious it was not just adrenaline running through his veins. Last we saw he was sliding down the stairs with emphatic thuds each step his butt hit.

Participant 4 aside, it was cool to see trends among heart rates and something we may keep in mind for future sets. We plan to explore other data collection points in future shows, to see what type clear data we can put behind a previously subjective point.