Illustrate, with concrete examples, the impact of microtonal scales on the melodic and harmonic characteristics of two specific musical traditions from the Middle East.

Microtonal scales, which include intervals smaller than the semitones found in Western music, have a profound impact on the melodic and harmonic characteristics of many Middle Eastern musical traditions. These scales allow for a much wider range of expression and nuances that are absent from the 12-tone equal temperament system. This analysis will explore the influence of microtonal scales on two specific traditions: the Arabic maqam system and the Persian dastgah system, detailing how these scales affect their melodic and harmonic structures.

The Arabic maqam system is a complex modal framework that utilizes a variety of microtonal intervals to define its scales and melodic possibilities. A maqam is not simply a scale but is a melodic framework with specific melodic motifs, characteristic phrases, and emotional associations. The use of microtones, often referred to as "quarter tones" (although these aren't always exactly a quarter tone), gives Arabic music its distinctive melodic flavor. These microtones exist in the spaces between the semitones of the Western scale, thereby allowing for a variety of melodic and ornamental possibilities. The melodic phrasing in the Arabic tradition relies heavily on the expressive use of these microtonal intervals. The "tahrir," a type of melodic ornamentation, often makes use of these microtones to create a sliding and wavering effect, adding emotional depth to the melody. The instruments such as the oud, nay, and qanun are specifically designed to play these microtonal intervals, enabling musicians to navigate the rich melodic landscape of the maqam system. The oud, a fretless instrument, is particularly suited to the sliding motions necessary for this tradition. The improvisation, which is central to the performance of Arabic music, relies heavily on these modal frameworks. The player often improvises within the melodic and rhythmic constraints, and they vary their ornamentation to create a unique expression of the maqam. The microtonal intervals contribute to the emotive effect, which is a central component of Arabic music tradition. Certain maqamat may emphasize specific microtones to convey unique emotional states. The scales aren't merely fixed patterns of intervals, but frameworks for creative musical expression, with different tunings that give rise to different expressive possibilities. The microtones give the scales a fluidity and expressive capability that is not possible with just Western scales. The complex melodic structures within this tradition are impossible to imagine without the nuanced use of microtonal scales.

The Persian dastgah system is another rich example of how microtonal scales shape the melodic and harmonic characteristics of a musical tradition. The dastgah, similar to the maqam, is a modal framework that includes a collection of melodies (gusheh) and characteristic phrases. Unlike maqam, the dastgah is considered to be a combination of melodic and rhythmic ideas that a performer builds from, instead of just being a scale. Microtonal intervals, often considered a range of microtonal degrees, play a key role in defining the expressive qualities of each dastgah. These microtones, often slightly different from the Arabic “quarter tones”, create nuances in pitch that are crucial to the melodies. These microtonal intervals are important to the emotional aspect of the music. Instruments such as the setar and kamancheh, both fretless string instruments, are designed to easily manipulate the microtonal intervals, creating the sliding and expressive melodic contours that characterize Persian music. The "tahrir" and “zireh” both play an important role in expressing complex emotional states with subtle use of ornamentations. The improvisational sections, which are important parts of a performance, highlight the use of microtones. These improvisations allow musicians to explore the modal characteristics of the dastgah and its gushehs, and the microtones help to define the expressive qualities of the improvisation. The rhythmic cycles are not as fixed as in other traditions. Persian music often emphasizes the interaction between the melodic improvisations of the musician and the subtle rhythmic nuances of the accompanying drum. Thus, the microtones help to facilitate a highly expressive and emotionally charged musical experience, and that emotional expression is central to the Persian musical aesthetic. The expressive capabilities of the music are expanded due to the use of these varied microtonal degrees that provide the means for nuanced emotional expressions that are simply not possible with the constraints of the Western 12-tone system.

In summary, the microtonal scales in both the Arabic maqam and the Persian dastgah systems have a transformative impact on their melodic and harmonic structures. They provide a rich palette of expressive possibilities that go far beyond the limits of Western tonal systems. They are therefore not simply variations in scales, but rather a fundamental aspect of these traditions. The use of microtones is not just a technical element, but rather a critical element for the emotive power, melodic expressiveness, and the overall identity of these distinct musical traditions. The nuanced use of these microtones makes these two traditions unique in the world, enabling them to offer their unique musical experience.