In 2006, The Knife’s Silent Shout was received with near universal acclaim. Pitchfork, who honored the Swedish duo with the title Album of the Year, recently hyperbolized that the siblings had created a masterwork that “arguably sounded like nothing before it.” Indie rock critics’ penchant for overstatement aside, the group does have a distinct sound—one that peculiarly hasn’t been co-opted by imitators at large.

Perhaps it speaks to the reverence hipsters have for their perceived groundbreakers, or maybe it just means that the gear they use is too obscure to reproduce. If voice transformers were as ubiquitous as Auto-Tune, would we be hearing The Knife pull a T-Pain on MTV complaining that they had been swagga-jacked? Well in honor of the release of Karin Dreijer Andersson’s new solo project, Fever Ray, I’ll demystify some of her and her brother’s sonic magic.

Very rarely is a band’s unique sonic character defined by a single effect but honestly, all songwriting and execution aside, there isn’t much that is wholly distinctive about the group insofar as sounds are concerned. The beats aren’t revolutionary and could very well have come from any can of prefab loops. The synth sounds are fairly generic and not treated in any inventive new way. The album itself is fairly quiet by today’s standards, perhaps attributable to a Swedish mastering job. The swelling synthesizer in “Silent Shout” actually pops out quite sharply and distinctly from the rest of the mix showing that the tune is not overly compressed. The tracks are immersed in several very artificial sounding reverbs, but that is not uncommon for electronica tracks.

Really, the only thing that grabs me about this group from a sonic perspective is the haunting vocal timbre. Layers of vocals with pitch-shifting, formant-altering effects contribute to this ethereal tone as provided primarily by the TC-Helicon VoiceLive. This handy little box allows the user to input a source program (instrument, microphone, etc.) and alter the pitch up to an octave in either direction, adjust the formants, loop, and add reverb.

Throughout the record, the sub-octave is the most used effect, although parallel 4ths and 5ths are occasionally audible and the super-octave is mixed in for flavor. In some instances, the “MIX BALANCE” fader is all the way up to 100% effect output such that Karin’s natural tones are inaudible. Other times they are mixed in tastefully with the dry vocal track. The sheer prevalence of this effect contribute to the conspicuous absence in the tracks where the vocals are unaffected. Songs such as “Keep the Streets Empty” sound all the more stark and vulnerable whereas the effected tracks have more body, presence, and strength.

One of the greatest tools in this gizmo is the formant filter. Formants are intrinsic resonances from an acoustic sound source. These in tandem with spectral content are what allow us to distinguish between human voices in the same range singing the same note or tell a Stradivarius from a Yamaha. The formant filter allows the user to alter the sonic quality of the output, thereby creating the effect of different singers and thickness or various otherworldly sounds.

It isn’t immediately clear to me whether or not the looping functions were especially useful to either The Knife or Fever Ray since looping facilities were surely available in their DAW, but the applications are very intriguing for live performance. An extant device that I like to use to a similar end is the Electroharmonix Microsynth. It has some of the same facilities although it doesn’t allow you to loop.

The use of such a filter is not unprecedented. Apollo 440 used the same device to similar effect back in 1990. Brian Eno famously used formant filtering in his 2005 release entitled Another Day on Earth. He has even accomplished similar ends with his famous suitcase ring-modulator that he has used throughout his storied career. So even though the predominant discriminator for both The Knife and Fever Ray is the vocal effect and even though there isn’t much that is revolutionary about their instrumentals, something in their approach to songwriting is what contributed to many critics touting them as some of the most unique sounding artists of our time. With all this in mind, it is important to stress again that there is a marked difference between obtaining an artists sounds and sounding like that artist.