Persian setar fret calculator
The setar's frets are loops of gut or nylon tied around the neck, and they include the Persian quarter-tone-like intervals: koron, lower than the tempered note, and sori, higher. Because the frets move, you can set them to a published system instead of guessing. This calculator starts on Hormoz Farhat's 17 notes per octave on a 660 mm (66 cm) scale.
Setar fret positions, Farhat's 17 notes, 660 mm scale
Pitch of each tied fret in cents above the open string and its distance from the nut, one octave.
| Fret | Cents | From nut (mm) | From previous (mm) | To saddle (mm) |
|---|---|---|---|---|
| 1 | 90.0 | 33.43 | 33.43 | 626.57 |
| 2 | 135.0 | 49.51 | 16.08 | 610.49 |
| 3 | 205.0 | 73.70 | 24.19 | 586.30 |
| 4 | 295.0 | 103.40 | 29.70 | 556.60 |
| 5 | 340.0 | 117.68 | 14.28 | 542.32 |
| 6 | 410.0 | 139.17 | 21.49 | 520.83 |
| 7 | 500.0 | 165.56 | 26.38 | 494.44 |
| 8 | 565.0 | 183.78 | 18.22 | 476.22 |
| 9 | 630.0 | 201.33 | 17.55 | 458.67 |
| 10 | 700.0 | 219.50 | 18.18 | 440.50 |
| 11 | 790.0 | 241.82 | 22.31 | 418.18 |
| 12 | 835.0 | 252.55 | 10.73 | 407.45 |
| 13 | 905.0 | 268.69 | 16.15 | 391.31 |
| 14 | 995.0 | 288.52 | 19.82 | 371.48 |
| 15 | 1040.0 | 298.05 | 9.53 | 361.95 |
| 16 | 1110.0 | 312.39 | 14.34 | 347.61 |
| 17 | 1200.0 | 330.00 | 17.61 | 330.00 |
How to use it
- Enter the scale length of your setar, nut to bridge. Most fall between 62 and 70 cm.
- Pick the Fret system: Farhat (17 notes per octave), Kiani after Mirza Hossein-Qoli's tar (15 notes), or the frets measured on a 66 cm setar (25 frets, two octaves and a fifth).
- Read each fret's pitch in cents above the open string and its distance from the nut. Print the template at 100% and check the 100 mm bar.
- Tie the frets on the marks, then fine-tune each one by ear or with the setar tuner: a tied fret moves a few millimeters with a push.
Help and explanations
In that system the re koron fret sits 49.51 mm from the nut (135 cents), re at 73.70 mm (205 cents), fa at 165.56 mm, sol at 219.50 mm and the octave at 330.00 mm, half the scale. Two more systems are in the menu, with a different spacing for the koron and sori frets.
Three fret systems, three sources
Farhat, in The Dastgah Concept in Persian Music (Cambridge University Press, 1990), describes 17 steps per octave: between C and D, for example, 90 + 45 + 70 cents, giving re♭ at 90, re koron at 135 and re at 205 cents. Between F and G the steps are 65 + 65 + 70, giving fa sori at 565 and sol koron at 630 cents. We take his values as summarized by Idin Samimi Mofakham (2023), rounded to 5 cents.
Majid Kiani's system follows the ratios of Mirza Hossein-Qoli's tar, 15 notes per octave: re koron 88/81 (143.5 cents, 52.50 mm on 66 cm), fa sori 243/176 (558.5 cents). The third option is the table measured on a 66 cm setar in Wikipedia's article, which places re koron at 54 mm (147.8 cents) and has frets 8 and 9 at 587.8 and 647.7 cents, higher than Farhat's fa sori and sol koron.
Tied frets, not fixed slots
New Grove counts 25 to 27 frets on a setar, each wrapped several times around the neck and knotted. Because they slide, the positions here are a starting point: mark them, tie the frets, and adjust each one against the open string or the next string while you play the dastgah you need.
Tips
- Mark each fret from the nut, never by adding up the spaces between them.
- Thicker fret material raises the string at that fret and adds a few cents; check each fret by ear with the string pressed on it, not by the mark alone.
- The strobe tuner shows cents to one decimal, handy for comparing a tied fret with its value in the table.
Frequently asked questions
How many frets does a setar have?
Usually 25 to 27 tied frets, according to New Grove. The measured 66 cm setar used here has 25, reaching two octaves and a fifth (1902 cents, 440 mm from the nut).
Where is the koron fret on a setar?
On a 66 cm setar, re koron is 49.51 mm from the nut in Farhat's system (135 cents), 52.50 mm in Kiani's (143.5 cents) and 54.01 mm on the measured instrument (147.8 cents).
What is the scale length of a setar?
Around 62 to 70 cm; 66 cm is a common reference. Measure from the nut to the bridge on yours, or double the distance from the nut to the octave fret.
What is the difference between koron and sori?
Koron lowers a note by roughly a quarter tone and sori raises it. In Farhat's figures, re koron is 70 cents below re, and fa sori is 65 cents above fa.
Where is the octave fret on a setar?
At half the scale: 330 mm on a 66 cm setar, and 1200 cents in every system in the table.