Radiohead’s BURN THE WITCH – Instrumental and Theoretical Analysis

It may clock in at under four minutes, but Burn The Witch is an incredibly dense track. The amount of precision and thought that went into every detail – even the ones resulting in indeterminacy – is staggering. Taking our past knowledge of how Radiohead creates music into account, it seems possible to understand many of those complexities, both in terms of the instruments/tools used and how they were employed. When Radiohead start the 2016 tour we will very likely learn about some new bits of gear which were used to craft the album, but the tiny glances we’ve had into their workflow on solo projects have been sufficiently illuminating that this analysis should (for the most part) stand the test of time.

Vocals



Thom’s vocals are unusually dry through the verses, with just a tiny bit of reverb to help them fit better in the mix. The choruses (“burn the witch) feature very specific bursts of well filtered reverb and delay. For example, there’s a burst of reverb in the left channel at 1:03-1:04 when Thom sings “witch”. Another case is the thick, dark (but rhythmically distinguishable) delay at 1:07-1:09 in the left channel while Thom sustains the word “burn”.

In addition to the primary vocals, from 3:04-3:24 Thom’s humming is layered over a sustained F# played by Ed. The humming fades in very slowly, so it can be hard to notice, but it’s really clear when you switch quickly between 1:16 and 3:08. Thom also adds some vibrato, while Ed’s note is played “clean”.

From the 2012 MOMA PS1 DJ set: Thom’s Roland Analog Echo DC-20 which may have been used for the thick, dark delays on Burn The Witch.

Orchestra

Photo posted by Robert Ziegler on twitter (since deleted) of when he conducted an orchestra for Radiohead in September 2015. This was very likely the session for Spectre, but tracks from LP9 may have been recorded at the time as well.



The orchestra on Burn The Witch consists entirely of strings. This is distinct from Spectre, since the would-be theme song’s orchestration also included trumpets and french horns. However, the string players are really put to work on the new single, with extensive col legno and pizzicato playing.

From the start, Jonny uses several techniques simultaneous for particularly complex textures. We get plectrums on muted strings tapping out every eighth note, forming the true foundation for everything else. Low pitched pizzicato F#’s are mixed in as well. Then we get a col legno “thwack” on every third beat. On the third beat of the first measure, we get a single pizz. F#4, but in the second measure the players pluck eight notes starting on the the third beat and fade out quickly. There also seems to be a plucked C# on the off-beats of the first two measures which fades out by the third.

Then on top of this initial web we get small swells of higher pitch at 0:03-0:07 and again at 0:10-0:13, with a combination of both arco and col lengo crescendo’ing and decrescendo’ing over the course of two measures. This is made particularly effective by having the arco players on one side (left channel) and the col legno players on the other (right channel).

When we get the same “swell” during the chorus (at 1:17-1:29), it is peaked with short glissando bursts. The bursts accent the first and fourth beats of every other measure - a particularly effective syncopation.

The climax (starting at ~3:10) is marked by the low strings playing a much louder arco rhythm while the violins go crazy with short arco bursts. Jonny likes to write separate scores for very single musician, and during this section there are several violins playing completely out of sync. One way to achieve this might have been a technique borrowed from Penderecki: the Polish composer frequently has several instruments play the same pattern - only offset slightly from each other (example video of Threnody for the Victims of Hiroshima). It seems possible that Jonny used this technique to make several violins stress the same note with seemingly at random. Another options is that Jonny gave each violin players an option to choose between patterns on each measure. By giving several players multiple patterns to choose from, they would almost always end up picking different patterns, and (if the patterns are written to enable it) would play at different times despite being in time with eachother. Jonny used the latter technique in his score for Water, and I think that it is more likely what he used for Burn The Witch.

We get an F# major triad at 3:23, but the pattern violins remain on F# until 3:34-3:36, when they join together to play B#* and then finish on C#.

*Clearly a raised scale degree to reach C#, so B# is more appropriate than C natural.

A screenshot from Jonny’s score to Water (from fabermusic). Note how each instrument can select between one of two patterns. The players are not meant to make these decisions together, but instead are meant to choose individually and to overlap or clash by chance/indeterminacy.

Electric Guitar + Effects

I think that Ed makes himself most evident with a pair of sparkly high pitched guitar strums at 0:51 and 0:54. There’s some sustained notes panned center through both choruses (technically starting at 0:51 as well) which I think we can attribute to Ed as well (if you’re having trouble hearing these, listen for when the F# cuts out at 1:20, then re-enters air 1:24).

For the two strums, Ed likely used his Electro-Harmonix HOG or HOG2 for an octave up shift plus his vintage EHX Deluxe Memory Man (or another delay with modulation) set with little feedback to thicken the sound. I’d guess HOG2 over Whammy V because lower pitched clean signal is present, just mixed much lower than the octave up (the Whammy doesn’t let you adjust the balance). They’re fairly clear sounding strums, which makes it unlikely that he used his Strymon Timeline’s Ice delay (very sparkly, but not clear), but some of that could be subtly mixed in as well. It also sounds like he may have used a very quick burst of his xguitar’s whammy bar at the start of the start of the first chord, which could suggest that he used one of his Fender Johnny Marr Signature Jaguars.

For the sustained notes, Ed’s “Sustainer” Strat is of course the most likely subject. During the first chorus, an F#4 (the one above middle C) is sustained almost non-stop. During the second chorus the F#4 drops out at 2:50, re-enters at 2:57, and then drops out permanently at 3:24. The tone of the sustained note is sort of like whistling – the fundamental is strong, and there aren’t many higher overtones. Perhaps Ed’s Electro-Harmonix HOG2 is at work in this case as well, with the filter turned down and the resonance fairly high. As mentioned previously, Thom’s humming is layered over the sustained note from 3:04-3:24.

Ed playing his Johnny Marr Signature Jaguar in 2012.

Ed’s early 2014 studio pedalboard build by Dan from TheGigRig. Although the EHX HOG2 is missing, it appeared on Ed’s 2016 tour board, and I suspect that Ed used a HOG or HOG2 via the pedalboard’s pair of send+return loops.



ondes Martenot

In addition to Ed’s center panned sustained notes at 0:51, there’s two higher pitched notes playing panned slightly right at 0:51-0:56. The timbre of these pitches is clearer (and more sine-like) than what Ed is doing, and the glissando from the first to the second at 0:54 makes me think that it is indeed a brief burst of Jonny’s ondes.

I also wouldn’t be surprised if there were ondes Martenot parts layered under the strings and/or Ed’s sustained notes. If some of the parts were originally sketched out on ondes, they may have been kept in very subtly – as the band did on How To Disappear Completely.

Right at the peak of the song’s climax, from 3:26-3:35, a sustained note with a good amount of vibrato fades in. The timbre is more synth-like than Ed’s sustained notes, and the character of the vibrato makes me think that this note is courtesy of Jonny’s ondes Martenot. If Ed is subtly contributing here as well, Jonny’s playing stands out more.

Jonny receiving the first new ondes Musicales in July 2011.

“Vocal” Bass Synth

The bass synth (present from 0:12-1:30) is really interesting in that it’s sound is extremely vowel-like. Additionally, the most distinctive/prominent frequencies are around and above ~650Hz (based on frequency analysis), but the fundamental frequencies of the notes are in the range of 82Hz to 185Hz for the initial verse F# and E bass-line. This rules out something like Thom’s Korg MS20, because even if the highness and lowpass filters were used with high resonance to accent frequencies between, say 650Hz and 1400Hz, the fundamental frequency would be absent (filtered out by the highness).* This paper on formant frequencies for different vowels lists 660Hz, 1720Hz, and 2410Hz as the formants for an “ae” vowel sound (with a fundamental pitch of 127Hz), which is quite close to what we hear on Burn The Witch. Radiohead are adjusting those frequencies on each note throughout the first verse and chorus, but it’s clear that formants are at work.

(*If you’re wondering how I know that I’m not imagining the fundamental frequency, I ran the it through a step low-pass filter at 200Hz and the fundamental frequency was still audible).

It’s possible that they used a parametric EQ with at least three bands and adjusted it as the song progressed, but a dedicated “formant” filter seems more likely. A lot of analog synths can do sound nasal with the use of bandpass filters or a lowpass-highpass pair (essentially a bandpass with more tweak-ability) – the Korg MS series and Yamaha CS series are good examples – but none are able to so distinctly produce a particular vowel sound as we hear on Burn The Witch. Additionally, the synth on the track is quite clear/clean sounding, while Thom’s Korg MS20 has a very “dirty” sound.

If I had to guess on what synth was used, it would be one of two things: Jonny’s modular synthesizer (perhaps with some new modules) or an Access Virus synth (which Radiohead have apparently used previously). There are quite a few filer modules in the eurorack format designed specifically to reproduce formants – including one by Analogue Systems (Jonny’s favorite) called the RS-360 Phase Filterbank – and it seems reasonable that Jonny used one of these on the track (although it’s possible that he used three stacked RS110 bandpass filters). If it wasn’t modular, then a digital synth with an analog sound like the Access Virus would explain how they achieved the complex filtering (the Virus TI has a “formant oscillator” option) as well as the “clean” sound. The Virus would also make switches between formants (such as that from “aa” to “ae” that occurs over the course of 0:16-0:20) easier to achieve, although they are definitely doable with modular means.

Thom and Jonny messing with Jonny’s swanky new modular synth setup in 2014. The results of this particular sessions almost certainly ended up on the UK Gold Soundtrack, but the fact that Jonny is experimenting means that his acquisition a new formant filter module would not be at all of a surprise.

Bass Guitar

I don’t know whether Colin played the bass synth, but he really shines when his distorted bass enters at 1:43. The third verse (second half of the second verse?) is really his time to shine! He also fills out the bottom end very well during both of the choruses, and, although his playing is less discernible, his sudden presence at the start of each chorus helps to demarcate it suddenly from the verse. His bass tone is really clear and focused, and the distortion is almost certainly courtesy of his amplifier’s natural overdrive. It sounds exactly like his trusted white 1972 Fender Precision Bass into his Ampeg SVT-Classic: simple, but perfect.

Colin with his vintage Fender Precision Bass and backed by a pair of Ampeg SVT-Classic amplifier heads in 2006.

Percussion

With all of the percussive strings playing, it’s no wonder that percussion is sparse on Burn The Witch. Every percussion hit that’s present is extremely well placed and specifically adjusted for its placement. They didn’t just turn on a drum machine, they either adjusted it constantly as the song played or programmed it with extreme detail beforehand – probably a bit of both. It’s hard to guess who’s responsible for drum programming, since Thom, Jonny, Colin, and Phil have all programmed beats for Radiohead songs in the past (Colin also programmed the beat for Guess Again! on Tomorrow’s Modern Boxes).

Whoever the main person behind the beat, the percussion sounds themselves seem to have been produced with Thom’s Elektron Analog Rytm. The persistent “hi-hats” are likely courtesy of the machine’s sampling capabilities, while the kick and snare (enter at 0:13, but especially prominent at 1:28) are likely made with its internal analog percussion synthesizer. That said, Phil’s Dave Smith Instruments The Tempest could just as easily have been responsible for those analogue kick and snare sounds. It’s possible that different drum machines were used for the hi-hats (perhaps Thom’s Elektron Machinedrum), but if I had to guess on one box it for all of the percussion sounds it would be the Analog Rytm.

Jonny mixing on Nigel’s Dalcon console from Nigel’s twitter on May 12 2015. Whether or not this picture is from the mixing of LP9, a great deal of the album was almost certainly run through it.