Leitmotifs

A useful sorting of the motifs in Wagner's Ring cycle with notation and synthesised audio. And a vidoe playlist of the same

Purcell What power art thou

The chromatic motion is in the vocal line combined with the pulse to a unique result:

Johannes, Robert and Clara

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

Old and older

Recorded at the cathedral where it was first performed, this performance highlights the spatial dimension of the music (a topical subject but we sometimes forget the long history of sound disposition in spaces):

The string writing is, of course, very effective (score from imslp).

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):

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.

Harmony

An approach to learning  harmony and developing harmonic language that extends beyond traditional tertiary-chords. 

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

Gesualdo

Some of the most extraordinary music we have with dramatic harmonic shifts:

His life was also rather strange and dramatic.

Monteverdi

Lamento della ninfa from the 8th book of madrigals (performed by La Venexiana):

The text with English translation.

Schoenberg's 'timbre' piece

In his book on harmony Schoenberg remarks that " it must also be possible to make progressions out of tone colours....progressions whose relations with one another work with a kind of logic entirely equivalent to that logic which satisfies us in the melody of pitches."
This is often linked to the 3rd of his orchestral pieces:

Henry Cowell

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

film music - learning from the masters

It pays to study the music of the past (only ca. 40 years but that counts as distant past in this era):

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

Bulgarian choral music

Interesting harmonic, rhythmic, and melodic practice growing out of traditional Bulgarian folk Music. Both video and audio sections (for example listen to excerpts from POLEGNALA E TUDORA PILENTSE PEE or VESELI TRANSKI PESNI the later includes an instrumental section). Also some videos:

Grieg - Lyric Pieces

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

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