The song starts with an arpeggiated synth. Though the synth in the video appears to be a Roland Juno(106?,60), this is believed to be a sample from a House song by Frankie Knuckles, entitled "Your Love" .

I think this is such a simple arpeggiated pattern it could easily be done in any number of ways. Anyway this is where the interesting stuff happens: They are employing 3 Roland SP-555 's. Watching the performance aspect of this video, not only are they doing the standard bit of just triggering loops on and off, but actually playing the sampler like a multi-mapped sampler. Though this process has immense creative potential, thinking about trigger pad 4, then 6 for a similar song can be insanely confusing live.

"My Girls" video: Despite all of this, musicians are making great use of this piece of gear. Below is a YouTube of a guy showing beginners potential of what can be done with the 555:

While being a bit clinical and not in English, this guy and his unfortunate watch tan line, show the basic features of what this great piece can do:

Obviously functionality is important, this modest YouTuber demonstrates how easy it is to loop phrases in the SP-555:

While it is no new trend to be using a phrase sampler as a keyboard instrument, bands like Dillinger Escape Plan and Ink & Dagger have been doing the same things with the Roland SP-808 over 10 years ago. I do think bands like Animal Collective show the true potential of phrase samplers being one of the instruments of the future. I do however question whether companies like Roland need to devise a better labeling system for the 16 trigger pads. If this is going to become a real instrument of the future for the masses, this will need to be amended. The level of number memorization needed to make this a great performance tool is very unfriendly to a musician used to a 12 tone scale. Imagine trying to remember which number pad triggers a sound for a 12 song set???? I find it interesting that many people aren't mapping out these samples on a traditional keyboard. All of these phrase samplers allow MIDI input for keyboard mapping, which can make the phrases translate to much more musical terms if properly mapped.

When everyone in keyboard land is forecasting the death of hardware samplers and the like, manufacturers like Roland should realize that the place these instruments will be used is live and not in the studio. The development of ways for musicians to map phrases in a easily labeled, high storage capacity sampler will be priceless and move music forward in the way AC is doing with this track. They along with bands like Battles , and Yeasayer and are setting the trend for the future of the phrase sampler as an instrument and I am sure more bands will be following their lead.