THE SCIENCE AND APPLICATIONS OF ACOUSTICS - H. H. Arnold ...

518 18. Music and Musical Instruments18.5 Key NotationThe keynote denotes the note with which any given scale begins. The tonic is thekeynote of the scale, whether the latter is a major or a minor scale. Many shortcompositions are written in one key only, but more elaborate musical pieces mayshift from one key to another. The key signature of a musical piece is denotedby the number and arrangement of flats and sharps following the clef sign at thebeginning of each staff, or it may appear only once at the beginning. Figure 18.12shows some of the most common key signatures for different major and minorkeys.Major and minor keys play a role in determining the mood of music. In earliertimes, a key may have been selected by a composer because a number of windinstruments were able to play only in certain keys. Certain desired effects may bebetter achieved on more flexible instruments in a specific key than another key.As Machlin pointed out, romantic composers developed affinities for certain keys,for example, Mendelsohn preferred E-minor, Chopin leaned toward C-sharp, andWagner made use of D-flat major for majestic effects.Whether it starts with C, D, E, or any other tone, a major scale follows the samearrangement of whole and half steps. Such an arrangement is known as a mode.All major scales typify the arrangement of whole and half steps.The minor mode serves as a foil to the major. The principal difference from themajor is that its third degree is flatted. For example, in the scale of C, the thirddegree is E rather than E. In a natural minor scale, the sixth and seventh steps arealso flatted (i.e., C-D-E -F-G-A -B -C). The minor differs considerably from themajor in coloring and mood. It should not be inferred that the minor is deemed“inferior”—the nomenclature simply refers to the fact that the interval C-E issmaller (hence minor, the Latin word) than the corresponding interval in the majorscale.If a mode is not specified, the major is implied. For example a Minuet in Gindicates the G-major. The minor is always specified (e.g., Mozart’s SymphonyNo. 40 in G minor).To classical composers the tonal qualities of the minor key assumes a moresomber aspect (e.g., the funeral music of Beethoven and Mendelssohn) than thetriumphal portions of symphonies and chorales which are generally played in majorkeys. Also, the minor mode carries a certain exotic tinge to Western ears, and thus inthe popular view it was associated with oriental and Eastern European music. Thiswas reflected in such works as Mozart’s Turkish Rondo, a number of Hungarianstyleworks by Schubert, Liszt, and Brahms, the main theme of Rimsky-Korsakov’sScheherazade, and other musical pieces that passed for exotica.18.6 Loudness NotationLoudness depends upon the intensity of the musical signal. Although loudnesscan be measured objectively with the use of a sound-level meter, a conductor or