Electro-Harmonix Swello Attack Envelope Review

Attack—essentially the rate and intensity with which a note rises in volume from its point of creation—is one of the coolest musical expressions you can mess with. If you play an instrument from the violin family it’s a fundamental part of your vocabulary. It’s used frequently in synthesis to conjure spooky, low-gravity atmospherics, and it’s an essential tool for taking the front end off some psychotic Moog sound that might otherwise explode like a foghorn six inches from your ear. Guitar players know the potential of this effect well too. Volume swells can drastically recast a guitar line—evoking reverse tape, pedal steel, and deep space. But doing it well is not easy. Even on guitars like the Stratocaster that lend themselves to volume swells by design, it takes technique, practice, and usually a very flexible pinky finger to make it work right. Electro-Harmonix’s Swello, which has origins in the attack filter section of the POG2, can do a lot of that work for you. But it’s capable of more than simple swells, with the ability to generate envelope filter- and wah-like sounds, big synth-style pads that are ripe for looping, and much stranger fare.Swing in SmoothlyThough they can be mellowing, soft attack and volume swell effects aren’t always subtle. For many players that prize precise, immediate attack, they are anathema. Swello—especially in the sans-filter “green” mode—is great at backgrounding the effect and making it more subliminal. At the lowest attack levels, you can use Swello in a capacity similar to a compressor to soften picking irregularities. At slightly higher but still subtle settings, it imparts a beautiful legato quality to melodic lines—especially enchanting in understated or deeply ambient delay and reverb contexts. At much slower attack rates, it evokes lush pedal steel tones and remarkably natural volume pedal or cello-like effects. There’s a lot of range to explore in the attack control alone.'Swello ’s capable of more than simple swells, with the ability to generate envelope filter- and wah-like sounds, big synth-style pads that are ripe for looping, and much stranger fare.'While the Swello’s control set is minimal, players without experience in synthesis or in using filters and envelopes with guitar may find them less than intuitive. This isn’t a shortcoming of the EHX design—it’s simply inherent to the complex interplay between filter and attack effects. If you start twisting knobs casually and with no particular intent you can end up with filter and attack combinations that make a guitar sound 30 feet underwater—if not altogether absent. So, it pays to move slowly though these controls, observe the sensitivities in their interactions and pay attention to how very small, incremental changes—as well as where you play on the fretboard—can alter the response and output. Though getting to your destination can be tricky and require patience, there are many surprises to find along the way.Overtone OrganizerAs a player that uses volume swells as both an expressive tool and crutch, I loved Swello’s very natural volume pedal and cello-like effects. But I also own a POG2 and treasure that pedal’s capacity to add -2-octave content to an upswelling tone. That can be a preposterously big sound with reverb (the low synth parts in Vangelis’ Blade Runner opening sequence and the Golden Gate Bridge foghorn at the distance of a couple miles are a couple handy points of reference). And there’s plenty of it here when you get a deep resonant peak, slow attack, and filter modulation working in sync, and hang out on the low strings.As with the POG2, boosting the high frequencies can make the pedal sound less organic—and at times even a bit cloying. Some settings also introduce digital artifacts, most noticeable in the quackier, mid-forward envelope filter-style tones. These sounds can be fun, but they’re not the Swello’s strong suit (and may disappoint players that demand vintage Mu-Tron authenticity from envelope filters). That said, there are plenty of ways to use high-frequency emphasis for pleasant coloration and to shape the attack, and at many such settings the output is largely free of digital aftertaste.The VerdictSwello, as the name suggests, specializes in very cello-like volume swells that sound organic, and enable you to keep your fingers on the strings and your feet away from expression pedals. At less than $150, it’s a great value for the slow-attack effects alone. However, players who explore its compression-like dynamics and the vast, unconventional tones found at atypical filter frequency and modulation settings will discover that the Swello is far more than it appears—truly greater than the sum of its parts.