Music Recording Databases
DRAM: Database of Recorded American Music : Not just American music, but a diverse collection of recordings from folk to opera, Native America to jazz, 19th century classical to early rock and much more.
Met Opera On Demand: Streaming access to videos of more than 450 performances from the Metropolitan Opera.
Music & Performing Arts (from Alexander Street Press): Includes Music Online streaming audio: American Song, Classical Music Library, Jazz Music Library, Popular Music Library, Contemporary World Music and Smithsonian Global Sound for Libraries. It also includes The L.A. Theatre Works Collection and a digital version of the Garland Encyclopedia of World Music.
Naxos Music Library: A streaming audio service comprised of over 1.5 million recordings, over 100,000 albums and over 700 labels. Many works available in multiple performances, from multiple labels, and from different eras. Includes music notes, cover artwork, track list, instrumentation and publisher information; libretti and synopses of more than 700 operas and more than 40,000 composer and artist biographies.
Reel to Real: Sound at the Pitt Rivers Museum:'Reel to Real' is a project, funded by the Esmée Fairbairn Collections Fund, designed to catalogue, digitize and make available online, in gallery spaces and beyond the Pitt Rivers Museum's unique archival field recordings. The project website has now been finalized and includes information about and playlists from all of the Museum's original ethnographic recordings, video and interview resources, ethnomusicology seminars, our SoundCloud account and much more."
Music Score Databases
These databases are openly available online.
Art Song Central: A searchable/browsable archive of free, printable, public domain art songs. Includes key, range, IPA transcriptions for every German, French, Italian and Latin song in the index.
Choral Public Domain Library: Not just choral music. Contributor-generated (wiki) PDFs, midi files and more. "You can use CPDL to find scores, texts, translations, and information about composers."
Digital Music Collection, Sibley Music Library: The Sibley Music Library at the Eastman School of Music (University of Rochester) has an extensive digital score collection with stable URLs which may be printed and downloaded. They also have a link by which you may request the digitization of a public domain score in Sibley's collection.
The Henselt Library at European-American University: Public domain scores of rare nineteenth-century piano music: PDFs of over 2,000 rare scores of nineteenth-century piano music, many of which are not generally available elsewhere. The Henselt Library consists of public domain scores that are mostly for piano 2 hands, with a small number of concerto scores and reductions.
International Music Score Library Project (IMSLP): The goal is to create "...a virtual library containing all public domain music scores, as well as scores from composers (living or otherwise) who are willing to share their music with the world without charge." Contains not only full scores, chamber music parts and scores and vocal scores, but also now includes orchestral parts. More being added daily. Includes the Werner Icking Music Archive contents.
Internet Archive: Contains a surprising number of scores, particularly piano/vocal scores of operettas.
The Lester S. Levy Collection of Sheet Music: A treasure trove of popular American sheet music. "The collection spans the years 1780 to 1980, but its strength is its thorough documentation of nineteenth-century America through popular music."
Music Library Scores Collection: Made available by the University of Michigan Libraries. Comprised of over 1100 scores held in Music Library's general and special collections. Understandably Michigan-centric.
Online Resources for Music Scholars: Digital Scores: An insanely complete clearing house for digital LEGAL scores. Includes 78 (yes, 78) sites providing access to public domain scores, manuscripts, facsimiles, you name it. Some sites also include other documents and audio files. Contains many of the sites listed below.
The Open Hymnal: "This hymnal is a part of the Open Hymnal Project to create a freely distributable, downloadable database of Christian hymns, spiritual songs, and prelude/postlude music." Updated June, 2014. A wealth of information about public domain hymns plus PDFs of the hymns. (Link directly to the PDF.)
VARIATIONS Prototype: Online Musical Scores: From Indiana University. Viewable public domain scores with stable URLs. Easy navigation of the scores, but not set up for printing.