Presetatio by Aaro Yag Huro: Toe ad Voice Part II Toe ad Voice: A Derivatio of the Rules of Voice-Leadig from Perceptual Priciples Part II: Derivatio of the rules of voice-leadig By David Huro Presetatio by: Aaro Yag Some Abbreviatios G - goal A empirical axiom C - corollary D traditioal derived musical rule [D] o-traditioal derived musical rule ISE 599: Sprig 2004 The Goal G1. The goal of voice-leadig is to create two or more cocurret yet perceptually distict "parts" or "voices." Good voiceleadig optimizes the auditory streamig. 1
Presetatio by Aaro Yag [D1.] Toeess Rule. Rule. Voice-leadig should employ toes that evoke strog, uique pitch sesatios. This is best achieved usig harmoic complex toes. Huro: Toe ad Voice Part II [D7.] Avoid Octaves Rule. Rule. Avoid the iterval of a octave betwee two cocurret voices. D2. Registral Compass Rule. Rule. Voice-leadig is best practiced i the regio betwee F2 ad G5, roughly cetered ear D4. [D8.] Avoid Perfect Fifths Rule. Rule. Avoid the iterval of a perfect fifth betwee two cocurret voices. [D3.] Sustaied Toes Rule I geeral, effective voice-leadig is best assured by employig sustaied toes i close successio, with few silet gaps or iterruptios. D4. Chord Spacig Rule. Rule. I geeral, chordal toes should be spaced with wider itervals betwee the lower voices. [D5.] Tessitura-Sesitive Spacig Rule. Rule. It is more importat to have large itervals separatig the lower voices i the case of soorities that are lower i overall pitch. D6. Avoid Uisos Rule. Rule. Avoid shared pitches betwee voices. [D12.] Leap-Legtheig Rule. Rule. Where wide leaps are uavoidable, use log duratios for either oe or both of the toes formig the leap. D13. Nearest Chordal Toe Rule. Rule. Parts should coect to the earest chordal toe i the ext soority. D11. Cojuct Movemet Rule. Rule. If a voice caot retai the same pitch, it should preferably move by step. C3. Avoid Leaps Rule. Rule. Avoid wide pitch leaps. D14. Part-Crossig Rule. Rule. Avoid the crossig of parts with respect to pitch. D15. Pitch Overlappig Rule. Avoid "overlapped" parts i which a pitch i a ostesibly lower voice is higher tha the subsequet pitch i a ostesibly higher voice. [D16.] Semblat Motio Rule. Rule. Avoid similar or parallel pitch motio betwee cocurret voices. [D17.] Parallel Motio Rule. Rule. Avoid parallel motio more tha similar motio. ISE 599: Sprig 2004 D10. Commo Toe Rule. Rule. Pitch-classes commo to successive soorities are best retaied as a sigle pitch that remais i the same voice. [D9.] Avoid Toal Fusio Rule. Rule. Avoid uisos more tha octaves, ad octaves more tha perfect fifths, ad perfect fifths more tha other itervals. [D18.] Oblique Approach to Fused Itervals Rule. Rule. Whe approachig uisos, octaves, or fifths, it is best to retai the same pitch i oe of the voices (i.e., approach by oblique motio). [D19.] Avoid Disjuct Approach to Fused Itervals Rule. Rule. If it is ot possible to approach uisos, octaves ad fifths by retaiig the same pitch (oblique motio), step motio should be used. [D20.] Avoid Semblat Approach betwee Fused Itervals Rule. Rule. Avoid similar pitch motio i which the voices employ uisos, octaves, or perfect fifths. (For example, whe both parts asced begiig a octave apart, ad ed a fifth apart.) D21. Parallel Uisos, Octaves, ad Fifths Rule. Rule. Avoid parallel uisos, octaves, or fifths. D22. Exposed Itervals Rule. Whe approachig uisos, octaves, or fifths, by similar motio, at least oe of the voices should move by step 2
Presetatio by Aaro Yag Huro: Toe ad Voice Part II Oset Sychroy Priciple Part III: Perceptual Priciples ad Musical Geres 7. If a composer iteds to write music i which the parts have a high degree of perceptual idepedece, the sychroous ote osets ought to be avoided. Osets of omially distict souds should be separated by 100 millisecods or more. Asychroous Preparatio of Toal Fusio Rule. Rule. Whe approachig uisos, octaves, or fifths, avoid sychroous ote osets. ISE 599: Sprig 2004 3
Presetatio by Aaro Yag Priciple of Limited Desity Huro: Toe ad Voice Part II Ability to track cocurret parts 8. If a composer iteds to write music i which idepedet parts are easily distiguished, the the umber of cocurret voices or parts ought to be kept to three or fewer. Bach ad the umber of parts Priciple of Timbral Differetiatio ISE 599: Sprig 2004 9. If a composer iteds to write music i which the parts have a high degree of perceptual idepedece, the each part should maitai a uique timbral character. 4
Presetatio by Aaro Yag Huro: Toe ad Voice Part II Wessel's illusio (Wessel, 1979) Source Locatio Priciple A sequece of three risig pitches is costructed usig two cotrastig timbres Two descedig or oe ascedig? 10. If a composer iteds to write music i which the parts have a high degree of perceptual idepedece, the it is helpful to separate i space the various soud sources for each part. Musical Textures ISE 599: Sprig 2004 5
Presetatio by Aaro Yag Huro: Toe ad Voice Part II Coclusio 6 empirically established rules No-traditioal rules The uexplaied Exposed octaves & outer voices Motivic & rhythmic stream separatio Sese of directio ad pitch successios Nature & Nurture Aesthetics ISE 599: Sprig 2004 6