A minor

A minor (abbreviated Am) is a minor scale based on A, consisting of the pitches A, B, C, D, E, F, and G. The harmonic minor scale raises the G to G♯. Its key signature has no flats or sharps (see below: Scales and keys).

Its relative major is C major, and its parallel major is A major.

Changes needed for the melodic and harmonic versions of the scale are written in with accidentals as necessary.

Johann Joachim Quantz considered A minor, along with C minor, much more suitable for expressing "the sad effect" than other minor keys (Versuch einer Anweisung die Flöte traversiere zu spielen).

Whereas traditionally key signatures were cancelled with naturals whenever the new key signature had fewer sharps or flats than the old key signature, or had flats instead of sharps or vice versa (so, for example, D major changing to D minor would be notated with a key signature of F♮, C♮, and B♭ at the change), in modern popular and commercial music, cancellation is only done when C major or A minor replaces another key.

Backing track

A backing track is an audio recording on audiotape, CD or a digital recording medium or a MIDI recording of synthesized instruments, often of rhythm section or other accompaniment parts that live musicians play or sing along to. Backing tracks enable singers and bands to add parts to their music which would be impractical to perform live, such as string section or choir parts which were recorded in the studio.

Uses

Bands or solo musicians may use backing tracks to add extra instrumental or vocal tracks to a live performance, to enhance the sound (as in the employment of doubled backing vocals) or to replicate more closely the instrumentation heard on a recording (as in the use of additional recorded parts such as string sections which would be costly to reproduce live.) A singer or vocal group performing without a backup band may sing along to pre-recorded music. A music track without lead vocals may also be called a karaoke, minus-one track or playback. Music backing tracks are also available for instrumental practice and jamming by jazz musicians, to help beginning to intermediate performers learn to improvise over chord progressions. Backing tracks are also known as jam tracks. If bought commercially, backing tracks often use session musicians to play the instruments and backing vocals, rather than using the original recording of a song, because the rights to use the original performance of the backing parts of a song by a well-known band would be very costly to purchase.

C major

The C major scale consists of the pitches C, D, E, F, G, A, and B. Its key signature has no flats and no sharps.

Its relative minor is A minor and its parallel minor is C minor.

C major is one of the most common key signatures used in western music. Most transposing instruments playing in their home key are notated in C major; for example, a clarinet in B♭ sounding a B-flat major scale is notated as playing a C major scale. The white keys of the piano correspond to the C major scale. Among brass instruments, the contra-bass tuba is in C. A pedal harp tuned to C major has all of its pedals in the middle position.

Simplicity

C major is often thought of as the simplest key, because there are no sharps and no flats, and beginning piano students' first pieces are usually simple ones in this key; the first scales and arpeggios that students learn are also usually C major. However, going against this common practice, the Polish-French composer Frédéric Chopin regarded this scale as the most difficult to play with complete evenness, and he tended to give it last to his students. He regarded B major as the easiest scale to play on the piano, because the position of the black and white notes best fit the natural positions of the fingers, and so he often had students start with this scale. There are no black keys in the C major scale, thus it doesn't fit the natural positions of the fingers well.

Compact disc

Compact disc (CD) is a digital optical disc data storage format. The format was originally developed to store and play only sound recordings but was later adapted for storage of data (CD-ROM). Several other formats were further derived from these, including write-once audio and data storage (CD-R), rewritable media (CD-RW), Video Compact Disc (VCD), Super Video Compact Disc (SVCD), Photo CD, PictureCD, CD-i, and Enhanced Music CD. Audio CDs and audio CD players have been commercially available since October 1982.

Standard CDs have a diameter of 120 millimetres (4.7 in) and can hold up to about 80 minutes of uncompressed audio or about 700 MiB of data. The Mini CD has various diameters ranging from 60 to 80 millimetres (2.4 to 3.1 in); they are sometimes used for CD singles, storing up to 24 minutes of audio, or delivering device drivers.

At the time of the technology's introduction in 1982, a CD had greater storage capacity than a personal computer hard drive. By 2010 hard drives commonly had capacities exceeding those of CDs by a factor of several thousand.