Johannes, Robert and Clara

Tamás Vásáry manages to capture the intimate nature of this music:

Bartok - Bagatelles Op. 6

These short piano pieces are wonderful sources for examining innovative harmony (and rhythm, and composition technique, and ...)

Granados - Goyescas

A recording of Granados performing his own music (in 1916 remastered from piano rolls):

Simple Metric Modulation

A drum tutorial explaining metric modulation (with notated illustrations as a bonus):

Leoš Janáček

An innovative composer of music that often sounds deceptively simple:

He found inspiration in the intonations of this native Czech language by notating speech fragments he heard as melodies.

Scriabin

Russian composer Scriabin in a jazzy(!?) mood  - the 2nd of his op. 57 pieces (composed in 1908).
The Preludes op. 74 are more typical of his style and sound world:

And a score + annotation (scroll down) of the harmony underlying these piece.

Children's Songs

A set of short pieces from jazz pianist Chick Corea, here is #4:

Michael Finnissy

Find the English Country Tunes:

Humour

Playing with some familiar music

Berio

One of the foremost composers of the 20th century. Some recordings available on ubuweb. His folk songs are more then arrangements (and here is Voci a later piece which he subtitled folksongs 2). The series of sequenzas (e.g. viola, guitar) for solo instruments are a fantastic way to learn more about the instruments and imaginative ways to write for them. Coro integrates voices into the orchestra. His Sinfonia, particularly the 3rd movement, was discussed extensively. 

Ondes Martenot

One of the early (1928) electric instruments. An introduction about the instrument:

Henry Cowell

A pioneering and influential American composer. Described as "an inventor of sounds". Some of his short piano pieces are particularly striking:

Quartal harmony

•  Debussy's 3rd etude 'pour les quartes' 
• Ives The Cage. 
• Also listen to composers such as Bartok, Schoenberg, Hindemith.
• These, in turn, found their way into jazz - such as Bill Evans (with Miles Davies) and others

Grieg - Lyric Pieces

Construction of melody - elaboration, variation; phrase structure; use of simple harmony;

And the same melody in a different dress (+ unexpected modulation):

Serialism+

Here is Milton Babbitt's Semi-Simple variations:

 and a jazzed up version of it. The same band also playing some Ligeti.

Melody - flute solo

Two interesting pieces for flute: Debussy Syrinx and Varese Density 21.5 (various recordings available) the scores can be accessed: Syrinx and Density.  Here is a good article examining both pieces with reference to melodic construction and the influence of the earlier piece on Varese's composition. And an interesting discussion of performance interpretation in Density.

Xenakis percussion music

Rebonds A:

Rebonds A from Alpine Chocolate on Vimeo.

Some background about Xenakis and his work.

Live electronics

Some examples of music for solo instrument with electronic processing:

• Music for hihat and computer Cort Lippe
• The Twittering Machine Andrew May
• Sequitur XIV Karlheinz Essl (and other interesting pieces). 

Keith Jarrett

A pianist worth knowing: the opening of Paris concert with notated transcription (minor errors included):

 Vienna concert, his version of Summertime, and many more examples. An interesting film about his work across genres on stage and in the studio. And you can hear him playing the organ as well. And in collaboration with Saxophone player Jan Garbarek (another musician worth knowing)

Noise and Subtractive Synthesis

We use the term noise for:

a) auditory sensation arising in response to non-periodic sound waves/signals, with flat and dense spectral distributions (vibrational/physical frame of reference) 

b) auditory sensation that is undesirable/unpleasant/unintended within a given context, interfering with auditory sensations that are desirable/pleasant/intended (i.e. sounds) within the same context (cognitive/semantic frame of reference, focusing on communication)

 Vassilakis et al lecture notes 

Also see Truax about the meaning of noise. 

A tutorial about using filters for subtractive synthesis (see also section 4-3 & 4-4 Music & Computers). Noise elements are actually used in music often, a very interesting example is the work of Italian composer Luigi Nono. Other examples include Ryoji Ikeda and Carsten Nicolai (alva noto) - Impulse or Fades.
and this is an article explaining different approaches to noise generation refining our understanding of the range of possible sounds: 

Atomic noise

KRISTOFFER JENSEN (2005).
Organised Sound, Volume 10, Issue01, April 2005 pp 75-81
http://journals.cambridge.org/action/displayAbstract?aid=306542