Stockhausen on Electronic Music (1952-1960) --------- WDR Electronic Music Studio Tour (2015)
      The first half of this post will summarize the main points from a Stockhausen lecture given at the Oxford Union (England) on May 6th 1972, where the composer uses excerpts from his seminal electronic work KONTAKTE to demonstrate “4 Criteria of Electronic Music”.  This summary will also serve as an introduction to my post on the electronic and electroacoustic version of KONTAKTE (Part 1 of which can be found here).

     The second half - WDR Studio Tour - is a photo essay of a few of the electronic devices used to realize these 4 criteria (from my 2015 tour of the WDR Electronic Music Studio storage repository in Cologne).

"4 Criteria of Electronic Music" (KONTAKTE)
     After studying the harmonically-liberating methods of the 2nd Viennese School (basically Arnold Schönberg, Alban Berg and Anton Webern, who explored the chromatic scale through the use of unique ordered tone rows and intervals),  Stockhausen became interested in how sounds themselves were constructed.  To do this, he studied the timbre structure of primitive ethnic instruments (such as wood/metal percussion), as well as recordings of concrete sounds from daily life.  The goal was to artificially synthesize these sound timbres through electronic means, basically using equipment designed for radio station maintenance and measurement.  This collection of re-purposed equipment mainly consisted of impulse noise generators (which create "clicks/pulses" at different speeds), sine wave tone generators (sometimes also used to create overtone “partials” by layering sine tones), and noise generators (used in some earlier works, but not in KONTAKTE).  Additionally, frequency filtering, distortion, ring modulation, reverb and variable speed tape recorders were used to color or speed up/slow down recorded fragments or loops (as musique concrete). 
These 2 devices generated most of the basic source material for KONTAKTE.
The top device generated pulses, and the bottom device was used to mostly create low frequencies.
Many other pieces of equipment (variable speed tape recorders, etc...) were used to process or change the speed of the sounds recorded on tape loops (see section below). 
(KONTAKTE Realization score©
     With these concepts in mind, Stockhausen developed 4 Criteria of Electronic Music:
  1. Unified Time Structuring
  2. Splitting of the Sound
  3. Multi-Layered Spacial Composition
  4. Equality of Sound and Noise
1. Unified Time Structuring
     If a piece of music is dramatically sped up as a loop (without changing the pitch), then a specific tone and color timbre eventually results.  If the music has an even rhythmic structure (such as a Beethoven sonata), then the timbre would be "purer" than that from a piece which was rhythmically or melodically irregular (such as a Webern piece).  The reverse is also true - a short "noise", if stretched out to several minutes, could result in a piece of music with its own structure, or form.  From a pitch perspective, if a repeating pulse (click) is sped up to very high speeds (without pitch transposition of the pulse), it eventually becomes a held tone, and as the speed increases further, the pitch rises.

     In KONTAKTE, Stockhausen recorded pulses in irregular rhythms and then made tape loops of the recordings.  By changing the tape loop playback speed, different timbres and pitches were obtained.  In other words, a unique rhythm is transformed into a pitched noise by greatly increasing its tempo.  440 pulses per second would result in concert pitch "A 440" for example.  Broader noises of a wider bandwidth could be created by irregularly varying the speed of the loop (and/or the micro-durations between the pulses on the tape) to create a “cloud” of pitches (ie - aleatoric pulse velocities result in aleatoric pitches).  The level of “noisiness” is also based on the degree of aperiodicity (rhythmic irregularity) within the loop itself (as mentioned in the Webern example).  In fact "white noise" is a full range of pulses with speeds from 20 pulses per second to 16,000 pulses per second. 

     From this idea, one could say that a rhythm of pulses become a pitch, which could be used to create a melodic rhythm, which could then be used as part of a larger form.  Stockhausen calls this phenomenon "Unified Time Structuring", since it creates a continuum between very short events and very long structures.  Pitch and rhythm are basically the same thing, just at different levels of time perception, and timbre (noisiness) is related to the internal rhythmic irregularities of a sound.

Stockhausen Edition CD 3, Track 14: KONTAKTE Structure X (listening score excerpt, colored):
A pulse-based noise tone wavers and falls. At the same time its frequency-filtered bright tone layer ("pitch", essentially) becomes darker and then brighter again.  Then the pitch gradually zigzags down, slows down, plays a 7-note "melody", finally becomes individual pulses, gradually lengthening, etc...
     In KONTAKTE's Structure X (from 17:12), a pitched noise slows into a regular repeating pulse (and descends), which eventually becomes a repeating low pitch, becoming an “ooh” timbre.  This then changes it's overtone elements to create “ah”, “ee”, etc….
     (For an example of the opposite, with pulses increasing in speed until they become rising tones, see Dan Tepfer's informative demonstration page.)

2. Splitting of the Sound
     In this scenario, a central tone is held, but several “satellites” split off (rising/falling, spreading out into particles, etc..) and the sound timbre of the original central tone changes (becomes less complex).  Stockhausen describes this process as an example of a new kind of "form" in composed music.  In contrast to the traditional way of composing music, where themes are used to describe a feeling or travel through a dramatic arc, here the theme is basically the carefully-shaped transformation of a sound (done  in an “artful” way).  The listener is led through this process, and by paying close attention to the sound's journey, it's possible that his/her perceptions could even be “widened”.  By following the path of a sound, the listener, in a way, “becomes the sounds”, and as the sounds split apart, one could even try to split apart with it, becoming a "polyphonic being".

SE CD 3, Track 15: KONTAKTE Structure XI: A centerline tone is held, while parts of this tone split off on their own rising/falling trajectories.
     In Structure XI (starting at about 21:41, or CD 3 track 15), a held sound is split in 6 places where a layer peels off and goes on its own path:
  • 0:24 (brief split, like a shooting star)
  • 0:30 (gliss)
  • 0:47 (gliss into points)
  • 1:00 (oscillating)
  • 1:13 (rising, chopped)
  • 1:21 (rising/falling)
  • Etc.. (ending in blocks of white noise)

3. Multi-Layered Spacial Composition
     Stockhausen used KONTAKTE to further explore motion in space (which he first explored in GESANG DER JÜNGLINGE), this time with a new "rotation table" which was able to spin a mounted speaker, allowing 4 microphones to capture the sounds as they passed by.  In playback, the sound would appear to be rotating among 4 speakers.  Besides directional location (360 degrees), Stockhausen also experimented with the creation of sounds at different distances from the listener - in other words, depth perception.  In KONTAKTE there are up to 6 levels of distance from the listener for each sound.  When several sounds are stacked as multiple layers, a feeling of depth is created by chopping out gaps in one layer (like cutting open windows ) to reveal the layer or layers beneath.  This immediate contrast is designed to clearly demonstrate the differences in sound distances.

     This idea is pretty interesting because spatial motion is typically envisioned (at least by me) as a "ring" around the listener.  The added element of depth turns this ring into a "disc".

     Stockhausen mentions a few important elements to depth perception in sound:
  • Familiarity of the sound (an unknown sound will not have anything for the listener to compare with for distance characteristics)
  • Dynamics (loud is close, quiet is far)
  • Distortion (diffusion, reverb, echoes etc…)
     In KONTAKTE, far away (“wet”) figures are also highlighted by close (“dry”) figures passing in front.  This is an example of using contrast to highlight foreground and background elements.  Stockhausen asks that the listener must believe only his/her ears, and try to forget about what one sees (or knows).  This is a very important mindset to have when listening to “new music” - do not believe one's eyes – believe one's ears.
Stockhausen demonstrates how a rotation table is used in KONTAKTE
(from what I've heard, this photo features a "stand-in" table,
the table actually used in KONTAKTE is shown a few pages down).
      In his lecture, Stockhausen plays Structure XII (23:58, CD track 16).

4. Equality of Sound (or "Tone") and Noise
     A noise is made of irregular/aperiodic sound pulses, and the”spread” of a group of noises determines a bandwidth (as described in Criteria 1).  Traditionally, “noise” was a taboo compositional element because notated music originally concentrated on indicating intervals between sung vowels (consonants were excluded or only used to mark a rhythmic punctuation).  Now, with electronic sound synthesis,  a continuum from tones to noises can be expressed as a scale.  However, the use of noise is not generally balanced equally with pure tones, since noises have a tendency to cover up tones (due to their "novelty").  For this reason, tones and noises must be balanced using special, unique scales.

     In KONTAKTE, Stockhausen used 42 different scales of different interval steps to manage his sounds.  Each sound, based on it’s bandwidth, was assigned 1 of the 42 scales.  A pure sound (very narrow bandwidth, clear pitch) would get a microtonal scale (very small interval steps), since it is very easy to perceive small scale steps in pure pitches.  A noisy sound with a large bandwidth would get a scale with large intervals, since large intervals are needed to make the differences in complex noises perceivable.  The widest bandwidth noise stretched covered a full 2 octave bandwidth, and it was assigned a scale based on intervals of a 5th (12 notes of this scale would actually cover the entire audible range for humans).

     This matching of sounds to scales was a revelation to Stockhausen, in that he realized that this was the first time that the “material” determined the “form”.  This concept would echo on into the far future operas of LICHT.

Stockhausen Edition CD 3: ETUDE, STUDIE I & II, GESANG DER JÜNGLINGE, KONTAKTE: Sound samples and CD ordering 
Stockhausen on Music : Four Criteria of Electronic Music (Maconie edited transciption)
The Concept of Unity in Electronic Music (Stockhausen, Perspectives of New Music Vol. 1, No. 1)
Stockhausen Lectures on DVD
Four Criteria of Electronic Music Pt 1 (YouTube)
Four Criteria of Electronic Music Pt 2 (YouTube)
"From Tape Loops to MIDI, Karlheinz Stockhausen's 40 Years of Electronic Music" (Manion)
Rhythm / Pitch Duality: hear rhythm become pitch before your ears (Dan Tepfer)
WDR Studios Vintage Pictures & Video Tour (120 Years of Electronic Music)
Discovering Electronic Music (1983)

The WDR Electronic Music Studio
     In 2015 I was able to visit the WDR (Westdeutscher Rundfunk/West German Radio) Electronic Music Studio repository space.  Below are a few photographs of the equipment used during the early years of Stockhausen's electronic music explorations.  Nowadays it is possible to hear these sounds created by online software, such as at this site.  In retrospect, it's very amazing that Stockhausen and his peers were able to create synthetic music out of radio testing equipment.  With some exaggeration, you could say they made a motorcycle engine out of toaster parts...
All inset pictures ©

1/3 Octave Bandwidth Filter. Functions like a graphic EQ.

Top: Heathkit Sine/Square wave generator (tone oscillator), (used in KONTAKTE, etc...)
Bottom: Tone (sine wave) generator (different than the frequency amplifier/feedback filter in the inset photo)

Left: Beat frequency oscillator. Used to change the resonant frequencies of input pulses.
Right: 2 Pulse generators. Used to create noise pulses of different speeds and durations.

Active Octave (bandwidth) filter (custom made by WDR).  Accentuates different frequency bands (like a parametric EQ).

Tape loop on stand during a demonstration of tape loop manipulation by Volker Müller.
Inset: Behind Stockhausen (working on KONTAKTE) are several long tape loops stretched out and held in place by 3 small stands.
To the back wall is (left to right) a sine wave beat frequency oscillator (used since GESANG DER JÜNGLINGE), a signal (sine wave) generator,
and a 1/3 octave filter (sitting on top of the octave filter, also used since GESANG...).

The Rotation table used to spread the sound over 4 microphone inputs in KONTAKTE.
Just to the left (on the shelf) are 2 beat frequency oscillators.

These devices are to be seen in the photo at bottom right of Stockhausen in 1975.
Left column: Tunable frequency amplifier, Bandpass filter, Tunable frequency detector amplifier/feedback filter
(used in GESANG DER JÜNGLINGE, KONTAKTE, etc... for "variable, relatively narrow filtering of impulses or noise bands, but also as a generator at extremely high feedback sensitivity.")  This device was used in KONTAKTE's Structure X to create the falling glissandi of slowing pulses.
Right column: Timer/counter, Sine wave sweep generator
(also used in MIXTUR to produce the base frequencies for the the ring modulation).

Stockhausen's Maihak W49 bandwidth filters and 2-channel faders (screwed on)
for live manipulation and EQ filtering of amplified sound signals. (KONTAKTE, MIKROPHONIE I, PROZESSION, many others...)

WDR Studio during the production of HYMNEN.
More WDR equipment photos are in the articles on STUDIE I & II, GESANG DER JÜNGLINGE, HYMNEN and MIXTUR, or in my Picasa WDR Album below.