Persian classical music is a modal tradition with deep historical roots. Its origins trace back to ancient Persia and the Sassanid era, where royal musicians like Barbod devised seven “Royal Modes” and hundreds of melodies (one for each day of the year). Over centuries these oral traditions evolved into the radif: a repertoire of hundreds of melodic pieces organized by mode. In the 19th century, under Qajar patronage, this radif was formally codified into suites called dastgah (each with its own sub-modes or avaz), largely thanks to masters like Mirza Abdollah and Aqa Hossein-Qoli Farahani. (By this time the radif encompassed roughly 300–400 pieces arranged into twelve dastgah suites.) In the early 20th century, Ali-Naqi Vaziri introduced Western theory to Persian music: he devised notation for the microtonal intervals (using the sori (half-sharp) and koron (half-flat) symbols) and tried to explain Persian modes in Western terms. Despite Western influences, the Dastgah system remains central to Persian music today, linking past and present.

The Dastgah system is a hierarchical modal structure. A dastgah can be thought of as a family of related modes and motifs, not just a single scale. Each of the seven principal dastgahs contains several melodic segments (or gushes) that define its character. In Qajar-era theory the seven principal dastgahs were identified as Shur, Mahur, Rast-Panjgah, Segah, Chahargah, Nava, and Homayun. (Additional sub-modes, called avaz, such as Bayat-e-Turk or Dashti, are usually counted under Shur, and Bayat-e-Esfahan under Homayun.) In practice, performances in a given dastgah begin with an introductory piece (daramad) that establishes the main mode. Subsequent gushes may explore different tonal areas or related modes. Each dastgah spans roughly two to two-and-a-half octaves, combining tetrachords and pentachords in characteristic patterns. (Indeed, Persian modes are built by concatenating tetrachords and pentachords, much like ancient Greek scales, rather than thinking strictly in fixed major/minor scales.) The ordered sequence of gushes in a dastgah’s radif guides performers through its lower, middle, and upper register, with each segment serving as a template for improvisation. In short, a dastgah is “a collection of discrete and heterogeneous elements organized into a hierarchy” – essentially a named system of related modes.

Musically, Persian classical music uses microtones. Octaves are divided into 24 equal quarter-tones, as first formalized by Vaziri. This allows intervals finer than Western semitones: Persian musicians speak of the 12 half-steps plus “half-sharp” (sori) and “half-flat” (koron) inflections. In practice, instruments achieve these microtones through movable frets or embouchure. For example, the Persian tar’s movable frets permit access to these quarter-tones, an “essential aspect of Persian musical scales (Dastgah system)”. Mastering these subtle intervals is key to authentic performance in any dastgah.

Major Dastgahs and Modes

The seven principal Dastgahs and Avaz are typically listed as follows:

• Shur – a deeply expressive mode. (Sub-modes/Avaz include Abu Ata, Dashti, Afshari, Bayat-e Tork, etc.)

• Mahur – bright, often likened to a major scale.

• Rast-Panjgah – heroic, roughly major-like.

• Segah – plaintive and introspective.

• Chahargah – powerful, often leading final ceremonies.

• Nava – a soothing, plaintive mode related to Segah.

• Homayun – rich and complex (with Bayat-e Esfahan as a sub-mode).

Each dastgah’s repertoire (its radif) consists of ordered gushes. The first gushe (the daramad) sets the tonal center of the dastgah. Later gushes often modulate subtly to different tetrachordal pitches to fill out the entire mode’s range. Each gushe spans only a few notes and serves as an improvisatory model. For example, after the daramad establishes the home notes, subsequent gushes may explore adjacent tetrachords to “complete the pitch scope” of the dastgah. Performers string these pieces together so the listening experience moves gradually through the lower, middle, and upper registers of the mode. These transitions are tied together by cadential formulas (forud) that always resolve back to the main tonality of the dastgah.

Key Traditional Instruments

Persian classical music uses a distinctive ensemble of plucked, bowed, and wind instruments. The core solo/melodic instruments include the tar, setar, santur, kamancheh, and ney. (Persian percussion like the zarb and dayereh provide the rhythmic pulse, but those are more folk-oriented.) Each melodic instrument is capable of producing the microtonal inflections of Persian modes. Tapadum’s selection includes these instruments so musicians can explore the Dastgah repertoire firsthand.

Tar

The Persian tar is a double-chested, skin-topped lute and perhaps the most iconic instrument of the tradition. Its body (often mulberry wood) is covered with a goatskin membrane, giving it a warm, resonant tone. The tar has six strings in three paired courses; originally it had five strings until Darvish Khan added the “mostaq” sixth string. Its long neck carries adjustable silk frets: thanks to these movable frets, the tar’s scale includes not only the 12 Western semitones but several semitone/quarter-tone intervals. In practice, the player selects about 7–8 tones (from up to 17 available) appropriate to the dastgah being performed. A small brass plectrum (mezrab) plucks the strings, while the left hand can squeeze and slide on the frets for expressive embellishments. Because its frets are movable, the tar can access all the microtones needed for any Persian mode – “an essential aspect” of the Dastgah system. Talented tar players weave complex ornamentations into their improvisations. The tar often leads a Persian ensemble and plays a prominent role in the Radif repertoire.

Setar

The setar is a smaller, long-necked lute, usually with four metal strings. (Historically it had only three strings until a 19th‑century mystic, Moshtaq Ali Shah, added the fourth.) The setar’s body is made of thin wood, giving it a delicate tone. Its fretting and tuning system is similar to the tar’s, allowing the player to render Persian microtones. Technique-wise, the setar is played with the nail of the index finger (instead of a plectrum). Its left-hand fingering is nearly identical to the tar’s, so it can execute the same quarter-tone pitches. Because of its soft, intimate voice, the setar is often used for more introspective or “spiritual” music, especially vocal accompaniment. (Historically, the setar’s design even influenced the development of India’s sitar.) In Persian ensembles, the setar offers a lyrical contrast to the deeper timbres of the tar and santur.

Santur

The Persian santur is a hammered dulcimer, trapezoidal in shape, with dozens of strings. (“Santur” literally means “hundred strings.”) The Persian santur has 72 steel and brass strings arranged in groups of four, stretched over movable wooden bridges on a walnut soundbox. By striking each set of four strings with lightweight wooden mallets (mezrab), the player can produce bright, shimmering tones. The strings on one side (steel) produce the higher pitches, while the brass strings on the other side give the bass notes. Each set of four strings is tuned to the same pitch, and the bridges can be adjusted to set the microtonal tuning for the mode. In performance the santur can articulate fast rhythmic patterns and delicate ornamentation alike. Its resonant, bell‑like sound adds sparkle to the ensemble. Because it can easily switch registers and dynamics, the santur is valued for both lively and lyrical sections. (Modern players use techniques like dead-hammering and subtle mallet angles to achieve Persian microtonal effects.) The santur’s versatility and clear tone make it a staple in Persian radif performances.

Kamancheh

The kamancheh is a spike-fiddle (sometimes called “Persian spike violin”) played upright on the knee. It has a round, skin-covered wooden body and traditionally three strings (now often four). The curved bow is held underhand, and one end of the bow hair is attached to a loose leather strap on the instrument, allowing nuanced control of tension as you play. This setup, along with its fretless neck, gives the kamancheh an exceptionally warm and vocal-like tone. Experienced players exploit its full dynamic range – from hauntingly soft melodies to powerful surges. In many ways the kamancheh serves a role similar to the violin in Western music: it can lead an ensemble or blend into rich harmonies. It is especially prized for its ability to mimic the human voice and ornamentation of Persian modes. The kamancheh is essential in both classical and folk traditions, frequently featured in Radif performances. Modern masters like Kayhan Kalhor have popularized its soulful sound worldwide.

Ney

The ney (or nay) is an end-blown bamboo flute and the primary wind instrument of Persian music. It is a very ancient instrument – in use in Iran for over 4,500 years. The Persian ney has five finger-holes and a thumb-hole (unlike Turkish/Egyptian nays), and is played by blowing across the beveled top edge of the reed. This “embouchure” is notoriously difficult to master. The ney’s tone is soft, breathy, and expressive. It can execute the quarter-tones by adjusting the partial covering of holes and subtle changes in lip shape. In practice, a player generates the ney’s signature plaintive sound by learning to produce consistent, resonant tones with the right flute angle and breath. In ensembles, the ney often provides a meditative counterpoint; in solo improvisations it can evoke the full emotional range of a dastgah.

Each of these instruments is inherently suited to Persian modes. Fretted instruments like the tar and setar physically accommodate quarter-tones, while fretless ones (kamancheh, santur) rely on movable bridges or player technique. The ney achieves microtones by half-covering holes or adjusting breath. By using these instruments to play the radif, musicians can faithfully express each dastgah’s subtle pitch relationships. For example, when performing Dastgah-e Shur on tar, the player will position the movable frets to capture Shur’s half-flat and half-sharp steps. Similarly, a santur is tuned with its bridges placed so that its 72 strings match the Shur scale (including its quarter-tones). In this way, each instrument and its tuning directly reflect the modal theory.

Practical Application for Modern Musicians

Today’s Iranian musicians continue this tradition by learning and improvising within the Dastgah framework. Typically one memorizes the Radif of a given dastgah (often through study with a master), then uses it as an improvisational guide. A performance in a dastgah usually begins with its daramad to set the “home” mode, and then moves through the other gushes to explore related melodic material. In doing so, the musician internalizes each mode’s rules: for instance, which notes can bend, which cadences resolve a phrase, and which tonal motives define that dastgah. Because Persian music prizes emotional expression, a performer will freely ornament and subtly shift pitch within those rules, using the instrument’s capabilities (slides on the tar or kamancheh, breath tone on the ney, etc.) to “color” each note.

Modern composers and fusion artists also draw on Dastgah theory. Understanding the scale patterns (built from specific tetrachords/pentachords) allows musicians to blend Persian modes with other musical styles. For example, jazz musicians in Iran often take a dastgah like Homayun (a minor-like mode) and improvise jazz melodies that still honor its microtonal scale.

Practical tools now exist to help contemporary players. Notation systems (using Vaziri’s sori/koron symbols) let one write down Persian melodies for study. Recordings of master radif performances are widely available for listening. And instruments themselves (such as the tar, setar, santur, kamancheh, and ney) can be obtained from specialized shops. (For instance, Tapadum’s ethnic instrument inventory carries authentic Persian tar and santur models.) By combining this equipment with theoretical study, a modern musician can access the full depth of the Dastgah system.

In summary, Iranian traditional music is a richly developed modal art. Its Dastgah system – a hierarchy of modes and melodic fragments – provides the theoretical backbone for composition and improvisation. Its unique tonal palette (24-quarter-tone octave) requires special instruments: the movable-fret tar, the delicate setar, the hammered santur, the bowed kamancheh, and the breathy ney, among others. Together, these elements allow Persian musicians to evoke centuries of musical expression and to create new works rooted in this enduring tradition.