The files are roughly organized by calendar day, which simplifies locating propers for upcoming celebrations. But please note: The indicated dates are only for organizing the files; it is absolutely necessary to consult a liturgical calendar or Ordo to determine which Mass is to be celebrated on a given day. In a few cases, the files contain chants that might not be used on the indicated day, but are interesting for historical reasons.
Unfortunately, it is not feasible to include explanatory notes in the files themselves. Chanters may find it helpful to consult the various editions of the Liber Usualis and Graduale Romanum , or ideally a Priest to indentify with certainty which chants are to be sung.
A nonchord tone NCT , nonharmonic tone , or embellishing tone is a note in a piece of music or song that is not part of the implied or expressed chord set out by the harmonic framework. In contrast, a chord tone is a note that is a part of the functional chord see: factor chord.
Nonchord tones are most often discussed in the context of the common practice period of classical music , but they can be used in the analysis of other types of tonal music as well, such as Western popular music. Nonchord tones are often categorized as accented nonchord tones and unaccented nonchord tones depending on whether the dissonance occurs on an accented or unaccented beat or part of a beat. Over time, some musical styles assimilated chord types outside of the common-practice style. In these chords, tones that might normally be considered nonchord tones are viewed as chord tones, such as the seventh of a minor seventh chord.
Chord and nonchord tones are defined by their membership or lack of membership in a chord: "The pitches which make up a chord are called chord-tones : any other pitches are called non-chord-tones. Such tones are most obvious in homophonic music but occur at least as frequently in contrapuntal music. According to Music in Theory and Practice, "Most nonharmonic tones are dissonant and create intervals of a second, fourth or seventh",  which are required to resolve to a chord tone in conventional ways. If the note fails to resolve until the next change of harmony, it may instead create a seventh chord or extended chord.
While theoretically in a three-note chord, there are nine possible nonchord tones in equal temperament , in practice nonchord tones are usually in the prevailing key.
Augmented and diminished intervals are also considered dissonant, and all nonharmonic tones are measured from the bass note , or lowest note sounding in the chord except in the case of nonharmonic bass tones. Nonharmonic tones generally occur in a pattern of three pitches, of which the nonharmonic tone is the center: . Nonchord tones are categorized by how they are used. The most important distinction is whether they occur on a strong or weak beat and are thus either accented or unaccented nonchord tones. An anticipation ANT occurs when this note is approached by step and then remains the same.
Earth's sixth mass extinction event under way, scientists warn | Environment | The Guardian
It is basically a note of the second chord played early. In the example below, the dissonant B in bar 1 is approached by step and resolves when that same pitch becomes a chord tone in bar 2. A portamento is the late Renaissance precursor to the anticipation ,  though today it refers to a glissando. A neighbor tone NT or auxiliary note AUX is a nonchord tone that passes stepwise from a chord tone directly above or below it which frequently causes the NT to create dissonance with the chord and resolves to the same chord tone:.
In practice and analysis, neighboring tones are sometimes differentiated depending upon whether or not they are lower or higher than the chord tones surrounding them. A neighboring tone that is a step higher than the surrounding chord tones is called an upper neighboring tone or an upper auxiliary note while a neighboring tone that is a step lower than the surrounding chord tones is a lower neighboring tone or lower auxiliary note.
However, following Heinrich Schenker 's usage in Free Composition , some authors reserve the term "neighbor note" to the lower neighbor a half step below the main note. The German term Nebennote is a somewhat broader category, including all nonchord tones approached from the main note by step.
A passing tone PT or passing note is a nonchord tone prepared by a chord tone a step above or below it and resolved by continuing in the same direction stepwise to the next chord tone which is either part of the same chord or of the next chord in the harmonic progression. Where two nonchord tones are before the resolution they are double passing tones or double passing notes. A neighbor tone where you step up or down from the chord tone, and then move back to the chord tone.
Endeavor, moreover, to introduce suspensions now in this voice, now in that, for it is incredible how much grace the melody acquires by this means. And every note which has a special function is rendered audible thereby. A suspension SUS sometimes referred to as a syncope  occurs when the harmony shifts from one chord to another, but one or more notes of the first chord the preparation are either temporarily held over into or are played again against the second chord against which they are nonchord tones called the suspension before resolving downwards to a chord tone by step the resolution.
The whole process is called a suspension as well as the specific nonchord tone s. Suspensions may be further described with two numbers: 1 the interval between the suspended note and the bass note and 2 the interval between the resolution and the bass note.
Anatomy of the ear
The most common suspensions are suspension, suspension, or suspension. Note that except for the suspensions, the numbers are typically referred to using the simple intervals , so for instance, if the intervals are actually an 11th and a 10th the first example below , you would typically call it a suspension. If the bass note is suspended, then the interval is calculated between the bass and the part that is most dissonant with it, often resulting in a suspension. Suspensions must resolve downwards. If a tied note is prepared like a suspension but resolves upwards, it is called a retardation.
Common retardations include and retardations. Decorated suspensions are common and consist of portamentos or double eighth notes, the second being a lower neighbor tone. A chain of suspensions constitutes the fourth species of counterpoint ; an example may be found in the second movement of Arcangelo Corelli 's Christmas Concerto.