SOLO

No. 19: SOLO for 1 Melody Instrumentalist with Looping Feedback System
1966 (10-20')

Form Scheme V
(© Universal Edition)
Development
     Stockhausen wrote SOLO on a commission by the Japanese radio network NHK in 1966. It's premiere performances featured trombone and flute soloists Yasusuke Hirata and Ryū Noguchi.  However, despite the title, the work required an additional 4 assistants to work its tape-loop-based sampling technology.  In more recent years this support team has been replaced by computer software (most recently running on an iPad 2) and so it now truly lives up to its title.  The compositional techniques Stockhausen uses here recall elements from MIKROPHONIE I (assembly of score from unsequenced notated materials), PLUS-MINUS (choosing material based on similarity/difference to what has just preceded it) and MOMENTE (independent sections which are influenced by the sections surrounding it), and then adds a new technological spin.
The original tape loop system required for SOLO's 6-Delay feedback set up.
(© www.karlheinzstockhausen.org)
      At its most basic level, SOLO is a work where a melodic (non-chordal) soloist plays aleatory (free-choice) phrases (assembled according to strict rules from a pool of notated material) accompanied by delay loops between 6 and 45 seconds long.  These delayed signals (echoes) become stacked at times, creating up to 5 or more layers at the same time.  The soloist's microphone signal is also sent into 2 channels, each of which gets its own independent looping set up.  So if there are 5 layers in each channel, plus the live soloist, then 11 distinct layers could possibly be heard at one time.  Perhaps for this reason most of the available scored phrases are either relatively quiet, or very slow, or both.  In order to add distinctiveness to each layer, SOLO also requires the soloist to come up with 4 distinct instrumental timbres (such as choosing different mutes for trombone, or different programs for synthesizers).

Scored Materials
     There are 6 unlabeled pages of score from which the soloist can draw single pitches ("elements"), phrases ("parts"), or full staff lines ("systems").  I think of these pages as a kind of "score pool".  SOLO is divided into 6 sections of different lengths, and 1 page of score is devoted to one section (it is left up to the soloist to choose which score page is used for which section).  In actuality however, many sections blur together somewhat, since parts from adjacent sections are often quoted and mixed together.  As indicated above, there are also 4 distinct timbres called for, labeled N (normal), I, II and III in the score. Additionally, on 2 pages three levels of "noisiness" (geräuschhaft) are asked for, which can be created through vocalization, over-blowing, electronic effects, etc...

     The 6 available pages in SOLO can be roughly characterized as below (I relabeled the 4 timbres T1-T4, since "normal" seems to be a relative term in my opinion).
Pool 1 Pool 2 Pool 3 Pool 4 Pool 5 Pool 6
T2 Equal mix Equal mix half T1-T3,
half T1		 T1->T3->T1 half T1-T3,
half T1
varying dynamics varying dynamics w longer note values & vibrato active transformations Fast short interval leaps, some noisy textures vibrato 12 contrasting systems,
some noisy textures


Pool 5 - Every system here starts as T1, transforms to T3 and then back. The arrows (-->) indicate gradual transformation from one timbre to another. 
(© Universal Edition)
Pool 4 - 2nd, 4th and 6th systems are at 3 levels of "noisiness" (geräuschhaft).
(© Universal Edition)

Score Assembly
     SOLO is assembled from the 6 page score pool into one of six possible "form scheme" structures (see sample at page top and in next section).  The bottom portion of the form scheme has the rules ("interpretation scheme") on how to assemble the notated materials.  Originally designed to be interpreted "on the fly", this was too hard to do for the performers, so Stockhausen recommended that a soloist should cut and paste sections of the notated pages to create a performable score. The interpretation scheme for Form Scheme I is interpreted (in English) below.

Formscheme I
(10'40")
Section A 
(1'06")		 Section B
(1'53")		 Section C
 (2'13)		 Section D
 (2'32")		 Section E 
(1'35")		 Section F
(1'20")
11 periods 
x 6 secs
 8 x 14.2 secs
 7 x 19 secs
 6 x 25.3 secs
 9 x 10.6 secs
 10 x 8 secs
similar contrary similar/different different/contrary similar/contrary different
parts elements/systems elements/parts systems parts/systems elements
quote from
next page		 quote from feedback quote from previous page
quote from previous/next page
short
pauses		 long
pauses		 short/long
pauses
medium/short
pauses		 medium
pauses
polyphony/
blocks		 chords/
blocks		 chords
polyphony/
chords		 blocks

     In the above table, Section A is divided into 11 sections ("periods") of 6 seconds each. A period defines the loop time (more on this below).  One complete system (staff line) from the score pool page fits into one period.  The period length basically defines the tempo (short periods translate into faster tempos).  The remaining rows of Section A are interpreted as "similar parts, but mixing in quoted material from the next section, playing short pauses between parts/quotes, and trying to create polyphony and blocks with the feedback layers".  Polyphonic means no silences, blocks means some silences and some reduced layers, chords means total unison with the feedback signal, resulting in contrasts of silences with full layers.
One chord, followed by two blocks:
---  ----------        ----   -- -
---  ---- --- -------------   - --
---  -----    ----  - - - -   -- -

Interpretation schemes of Form Schemes III and V are translated below.
Formscheme III
(15'25")
Section A 
(3'33")		 Section B
 (1'30")		 Section C
 (2'42")		 Section D
 (2'01")		 Section E 
(1'06")		 Section F 
(4'34")
7 x 30.4 secs
 10 x 9 secs
 8 x 20.25 secs
 9 x 13.5 secs
 11 x 6 secs
 6 x 45.6 secs
similar/contrary different contrary different/similar contrary/different similar
elements/parts systems parts/systems elements parts elements/systems

quote from previous/next page quote from
next page		 quote from feedback
quote from previous page
short/long
pauses
medium
 pauses		 long/medium
 pauses		 short
pauses		 long
pauses
chords/
blocks
polyphony/
2 blocks		 chords blocks polyphony/
chords

Formscheme  V
(17'6")
Section A 
(3'02")		 Section B
 (4'34")		 Section C
 (1'54")		 Section D 
(1'28")		 Section E 
(3'44")		 Section F
 (2'24")
8 x 22.8 secs
 6 x 45.6 secs
 10 x 11.4 secs
 11 x 8 secs
 7 x 32 secs
 9 x 16 secs
different different/similar contrary/different similar similar/contrary contrary
systems parts parts/systems elements/systems elements elements/parts


quote from previous /next page quote from previous
page
 quote from
last period of previous page		 quote from
next
page

medium

pauses		 long/medium
 pauses		 short/long
pauses		 long
pauses		 medium/short
pauses

polyphony chords/
part blocks w long pauses		 polyphony/
element blocks w long pauses		 chords polyphony/
chords

Feedback Layers
Form Scheme I
(© Universal Edition)
     The top part of the Form Scheme with the horizontal bars are ON/OFF instructions for the soloist's 4 assistants. Rows 1 and 2 are channels for "Microphone Pick-Up". Rows 3 & 4 are "Feedback" and 5 & 6 are "Playback" (each row pair is usually set as Left and Right).  Each shaded/lined area indicates an active channel for that period.
The effect of each channel is as follows:
  1. Mic - Save that period's material (loop) by recording the live sound to "Memory"
  2. Feedback - Add the loop as a new layer in Memory.  If the Mic is off, then no change to the loop. Erase Memory if Feedback is "off".
  3. Playback - Play any loop/layers stored in Memory (but not the newest layer just stored).  Playback always occurs before Feedback Memory is added to/erased.
For example, in Section A above this sequence happens for Channel 1:
  1. Record the live sound, save to Memory as Layer A
  2. Play back A (and keep it in Memory)
  3. Play back A (and keep it in Memory)
  4. Record layer B, add to A in Memory
  5. Play back A & B (save both in Memory)
  6. Play back A & B, then erase from Memory
  7. Record layer C, save to Memory
  8. Record layer D, add to C in Memory
  9. Play back C & D from Memory, record Layer E, add to C & D in Memory
  10. Play back layers C, D & E, keep all in Memory
  11. Don't play anything, but keep C, D & E in memory
     In the Form Scheme, the bottom-most Playback rows actually show the number of accumulated layers which will be played back from Memory (1 line for each layer) in each channel.  Layers accumulate until an "OFF" occurs in the Feedback channel.  The number of lines has no meaning to the players, but is helpful to someone following the Form Scheme while listening.  In most performances, the 2 channels for each assistant are divided into LEFT and RIGHT, but Stockhausen also recommends doing ad-libbed panning for the output channels, so it can definitely get confusing to follow all the layers.

     The shaded blocks also have numbers inside them (not clearly seen in the score sample).  These are the number of "perforations" in the recording or saving process.  An assistant must quickly drop and raise the input level in order to create silent gaps in the loop.  These are also ad-libbed.  Usually there only 1 to 4 of these perforation gaps, but a couple periods have 12 and 13.

     As one can imagine, with all of these factors at play, the results can be very unpredictable. 

21st Century Software
 
     This is a version of SOLO (Form Scheme I, performed on contrabass by Enrico Francioni) with all of the feedback layering handled by a pre-programmed iPad 2.  It's possible to actually see the faders moving to match the instructions in the Form Scheme above.  

     It's pretty interesting that there is now actually a small (tiny) cottage industry of people making SOLO-enabling software.  However on authorized recordings supervised by Stockhausen himself, a flautist plays to a pre-recorded tape of the feedback portion, and a synthesizer version is assembled completely on a digital sequencer with no live element at all.

Live Performance
Jason Alder performs SOLO (Form Scheme III) with Max/MSP controlling the Feedback Layers (music begins at 3:35 after a brief explanation)
International Clarinet Association ClarinetFest 2014
LSU Recital Hall, Baton Rouge, LA, USA, August 3, 2014

Sound Impressions
     SOLO takes single lines and figures and explodes them into kaleidoscopic shards flying through a hall of mirrors.  It was designed partly as an attempt to depict a soloist's thought processes while playing - thinking about what has been played and what is yet to be played.  From a listening standpoint it can be appreciated as six blended movements concerned with manipulating and layering looped live material (or as one long development-driven movement, since material from one section frequently carries over into the next).  The techniques used (by both the score assembler and the loop technicians) are very interesting, but in the final analysis they're more or less academic, since whatever music created from the Form Scheme is then atomized and obscured by perforation and layering of the feedback loops.

     I think that, like SPIRAL, a primary characteristic of a SOLO recording is simply the primary instrument, as well as any effects used to convey the 3 levels of "noisiness" (for example, some soloists have used ring modulators to create one of the 3 noise timbres).  In general, because of the mostly slow to moderate tempos involved, there are not many "hard" edges (though Michele Marelli's version for bassett-horn has some pretty wonderfully caterwauling moments).  Personally, I quite like the cello and contrabass versions, since they end up sounding something like polyphonic string quartets.  In any case SOLO was probably the very first solo "ambient soundscape" piece and yet it has apparently survived very successfully into the age of the mobile app.

Links
SOLO (Flute & Synth) Sound samples, tracks listings and CD ordering
Buy the Score
SOLO Wiki
SOLO (Form Scheme III) on cello, Arne Deforce with Max/MSP
SOLO (on tuned percussion, Benjamin Bacon) 
SOLO (on vibraphone, Derek Kwan, Form Sceme III, Live: YouTube, Recording: SoundCloud)
SOLO (Thomas Moore on trombone, & Juan Parra Cancino on electronics) 
Sonoloco Review of SOLO