So, you think you know EDM. You’ve been listening to all the latest players in the electronic music world, and you think you know what they’re all about — the unique, infinitesimal nuances of sub-genre that distinguish one from another. What you may not know is that all of these artists in almost all forms of electronic music, as different as they are, will almost invariably utilize the same type of device in the course of their work, the Low-Pass Filter, to achieve the anxious, escalating build that typically leads up to a cathartic release.
Let’s listen to a few examples.
Ignoring for a moment the claps, the crazy noises constantly rising in pitch, and the big drums building up into an epic drop, let’s look at this moment right at 1:00 into “In My Mind,” where everything seems to drop into nothingness and then slowly fade back into view. What’s happening here?
Everything is quiet, but hasn’t entirely vanished. In this case, the first synth sound quickly returns some presence, leading into the verse vocals. Then another dulled synth sound enters, and slowly gains more and more presence, building into a huge, classic drop with a soaring, epic synth melody.
Listen again at 3:15 and notice how the same basic effect occurs, but this time the effect is on the piano. And still, the build of excitement here is undeniable.
Next, take Machinedrum’s “Gunshotta.” Can you hear, in those jungle drums towards the beginning, how they seem to quickly fade in from nowhere? But, it’s not strictly a volume thing — no, there’s something dull about them at first, that makes them sound far away, and then quickly they become more present. It’s the same effect as the first track. As you listen, you can feel the excitement build.
Here’s another example from James Blake. At about 41 seconds in, a keyboard part subtlely begins to emerge, eventually wholly enveloping the listener by the time the drums hit at 1:09. Again, more of the same opening effect — he’s adding presence to a sound to build excitement. But how?
This all has to do with the frequency content of the signal, and how it is altered over time. Our ears are very sensitive to the frequency content of the world around us. For example, when something makes a noise far away from us, we hear less of its high frequency content and more of its low frequency content, giving it a dull, distant sound. In contrast, when something’s closer, it sounds brighter, livelier, and more immediate. It grabs our attention.
Higher frequencies naturally trigger our fight-or-flight instincts, alerting us to the fact that there might be a predator nearby. Imagine the sound of leaves crunching right behind you. Or a door hinge squeaking open. You’re ready for action!
Messing with frequency content in this way is literally manipulating our instinct to fight for survival, elevating tension and creating more buildup in the process. What all of these examples have in common is they each employ a Low-Pass Filter. It basically does just what it sounds like. It passes all the low frequencies through, while blocking the high frequencies.
When you modulate that filter in real time to let more and more high frequencies through, you can really mess with people’s instincts! Here’s one more example of how it can really drive the crowd wild:
Try messing with the filters on your synth of choice, and see what kinds of terror you can reign on your loved ones, coworkers, and really anyone in earshot. And then head over to our Filters course to learn about all the other kinds of filters there are!
Logic X Channel EQ Low-Pass Filter Sweep, image courtesy of Soundfly’s Demystifying Synths: Filters course.