Varispeed (changing the speed and pitch of audio like you could do with tape) is one of my favourite audio effects. It was more common in the analogue days because it was easier to slow tapes down that to do the equivalent with digital. [Cockos’ Reaper has a great varispeed facility but several DAWs (Sonar, I’m looking at you…) have yet to implement anything like it. This is actually one of the main reasons I’ve started to migrate from Sonar to Reaper.] Varispeed is the thing that lets you get the “Chipmunk” vocals.
But sounding like The Chipmunks isn’t why it’s interesting – that’s even to be avoided! Nor am I talking about slowing tape down to half speed, playing and guitar solo and pretending you’re Eddie Van Halen. That’s one possible use but is rather crude. No, it’s about getting new and interesting sounds out of the same instruments.
It was used in the piano solo of The Beatles’ In My Life to a nice effect. It’s also one of Lindsey Buckingham’s (producer/singer/guitarist of Fleetwood Mac) main production tools. Listen to ‘Tusk’ (or any album after that) to hear it used to manipulate all sorts of sounds.
It’s best used as a textural and tonal tool. I love slowing guitar down anywhere between a semitone and an octave, playing something and speeding everything back up. Not only does it change the timbre of the instrument, giving guitars a nice chiming quality, but it changes the temporal articulation. This allows you to get sounds that aren’t possible with playing things straight. Most of the instrumental lines I play with it are really rather simple, but it’s all about how the new texture makes them into something new. Listen to the ending of my track ‘Across the Sea’ where I’ve used a guitar recorded slower than the rest of the track, sped back up and added a bit of delay. It sounds like a cross between a guitar and a synth, without being so different as to sound out of place (to my ears).
Varispeed is also great for adding layers of the same instrument. Say you track one guitar at normal tempo. A fairly standard recording technique is to double it up by playing it again (in the same or different chord voice-ings) and panning them hard left and right. Either way, it’s going to sound like the same guitar. Another option is to use varispeed to slow everything down, play it again (with the key transposed down the appropriate amount) and speed things up to the original tempo. Depending on how much you slow it down you’ll either get a subtle change in timbre that will help it sit apart from the standard guitar or you’ll get an effect that makes it sound like something completely different. Which option you go for will obviously depend on the track.
Or you can use it purely to adjust the timbre to get instruments to sit in the mix, but this would have to be figured out during tracking so is probably most useful for home-studio types who can go back and rerecord instruments without having to book expensive studio time. Lindsey Buckingham said:
“It’s a voicing tool,” he says, “a way of refining a sound-the harmonics of it-so it sits right in the track. It’s like another version of EQ.”
I’ve never really used it like this intentionally but there are times when I’ve found the varispeed instruments sitting much more easily than the standard ones.
Something I’ve only explored a little is speeding the “tape” up while record and slowing it back down when mixing so that things have a slow-motion sound. The problem with this technique is that it doesn’t take much speeding up before the songs can become hard to play. I think it’s something worth exploring and have considered doing a track where most of the main elements are slowed down by varying degrees. A similar thing was done in Yeasayer’s ‘The Children‘ from their Odd Blood album.
So there are a few reasons why I think varispeed is a great tool. I can’t go back to Sonar until Cakewalk implements a useable version of varispeed that isn’t a work-around using pitch shifters. Those just don’t work.