Classic Stomp Box Close-up: Phase Shifter
What do Van Halen’s “Ain’t Talkin’ ’Bout Love,” “Eruption” and “Unchained,” Pink Floyd’s “Shine On You Crazy Diamond,” Yes’ “Starship Trooper,” the Rolling Stones’ “Beast of Burden,” Modest Mouse’s “Float On” and Jimi Hendrix’s “Spanish Castle Magic” and his epic reading of “The Star Spangled Banner” all have in common?
The first phase shifter went into mass production in 1968. Debuted by Univox, their device — called a Uni-Vibe — allowed guitarists to get sounds that could previously only be conjured via studio tape manipulation or by using a cumbersome Leslie cabinet with rotating speakers. The phase shifter creates a slight — or major — rippling sound by amplifying some parts of a guitar’s tone while reducing others. Essentially, it splits the signal in two and alters the character of one’s waves while leaving the other intact. And the interplay of those signals is what makes the device so aurally charming.
After the alternative rock era, when guitar heroics took a downturn in the mainstream once again, the popularity of the phrase shifter diminished, but it is seeing a resurgence today in part due to the stoner rock revolution led by groups like Queens of the Stone age and Josh Homme’s various spin-offs and, on the more sophisticated tip, sonically exploratory outfits like Explosions in the Sky.
The phase shifter can be romantic or abrasive. As a general rule, adding a small amount of phasing will gently color a guitar’s signal, providing a dreamy sonic quality that can be described as both warm and expansive. For an example, drop the needle — just kidding — on Pink Floyd’s “Wish You Were Here” and check out the “Shine On” suite and “ Have a Cigar.” But when it’s cranked up, the effect can roar like a blast furnace, as it does on Eddie’s visceral “Ain’t Talkin’ ’Bout Love” performance.
Compared to sampling devices and pedals designed for real curveball sonics, the phase shifter is easy to use. The classic MXR Phase 90, for example, has an on/off switch and one rubber covered pot. Click it on and turn it up or down — that’s the entire operating manual. The Phase 90 played a role in classic recordings by Eddie Van Halen and others. More sophisticated models have various options that re-EQ guitar signals or manipulate the rate of decay in the phasing and so on, Typically phase shifters sell for $50 to slightly more than $100 and up for models made by boutique companies, making them among the more affordable members of today’s stomp box family.
More complex shifters offer options like “stage selection” or “setting,” “depth,” “resonance” and “rate.” “Rate” may be the coolest control, and it’s what primarily comes into play with a one-pot model like the Phase 90. The higher the rate setting is increased, the more a guitar’s voice warbles. The finale of Hendrix’s “Angel” displays what this aspect of phase shifting sounds like with a clean tone, and “Little Wing” does so with some juicy overdrive.
“Depth” is similar to a vibrato function, determining the span of the warbling quality. Once again, this characteristic increases dramatically when turning up a classic one-knob device, but can be controlled with a high degree of precision with a multi-knob pedal with a “depth” setting.
“Resonance” is subtler, serving as an EQ to color the signal, usually sculpting the top end. This is a nice feature lacking from the simplest members of the phase shifter family.
The “stage” or “setting” function flips the phase shifter into various sonic and performance templates. Several phase shifters offer 10 positions, and each setting has a distinct foundational character that blends the above characteristics and serves as a platform to tweak tones from.
Two other controls that sometimes appear on phase shifters are “rise” and “fall.” “Rise” accentuates the portions of the altered signal that reflect the actual note being played, while “fall” accents the phasing peaks of the treated signal.
In general a phrase shifter responds best with brighter guitar sounds, since its effect is most prominent in the treble range. So if you’re just beginning to work with any kind of phase shifter start with your guitar on the treble pick-up setting until you’ve got a command of what the pedal can accomplish.