The measured reverberation time in Hagia Sophia is about ten seconds for a sound source in the apse and slightly over eleven seconds for a sound source in the space under the dome when the church is empty.[1] The long reverberation time is due to many elements among which are the immense interior volume of 255.800 m3, the dome and semi-domes, the nestling of architectural volumes, and the reflective surfaces of marble and gold mosaic.[2] This long reverberation remains uniform across a vast spectrum of frequencies in the range of the singing human voice, from 200 Hz–2,000 Hz (Fig. 53–55).[3] It reaches a peak of twelve seconds at frequencies 250–500 Hz and reduces to ten and eight seconds respectively for frequencies in the range 1–2 kHz (Fig. 54).[4]

Pentcheva2017_Fig53T30HatFig.53 (above)


Pentcheva2017_Fig54WieslawWoszczykFig.54 (above)


Pentcheva2017_Fig55AcousticalhistoryofHagiaSophiaFig.55 (above)


The way the kallichorosis enveloped by aisles and galleries enable the space under the dome to mix quickly the reflected sound energy and to remain full for a long period of time. The enveloping sound of the kallichorosconstitutes a characteristic of some of the best concert halls. Yet, the duration of this reverberation in the Great Church is extremely long and that sets it apart from the modern performance spaces; their RT, by contrast, is often less than two seconds.[5] Because of this, clarity and intelligibility of speech in Hagia Sophia is poor overall, even in the space under the dome.[6]

The long sustain of the late field reverberation and enveloping sound present room acoustics well suited for sung vocalization and especially monody.[7] The kallichorosresponds to the chant in the entire range of the human voice by producing high-frequency harmonics, thus the singers’ notes smeared over time end up harmonizing with themselves. (Figs. 56–57). The choristers can use the space as a musical instrument that gives body and fullness to their voices. They can interact further with the high frequency harmonics produced by the space and create a form of polyphony emerging from the synergy of the singer’s output and the resonant and sustained return of the chamber.

Pentcheva2017_Fig56ProkeimenondryFig.56 (above)

Pentcheva2017_Fig57ProkeimenonwetFig.57 (above)


The interior causes two important acoustic effects. The first is amplification as the sung notes are sustained for a long time. A gradual build-up emerges as more sound energy is continually added and slowly absorbed. This phenomenon produces a fuller and richer sound. The second effect is that of overlapping and dissolving of notes. The building responds to the monody by producing high-frequency returns that interact and gradually evolve from dissonant to consonant harmonics.[8] This second effect leads to a brighter sound; a phenomenon further enhanced by the domes and semi-domes. Raised almost fifty-seven meters above the floor, the cupola reflects and scatters the sound waves, producing the effect of an acoustic rain over a much wider area of the floor.[9] The dome causes the high-frequency short-wavelengths of the harmonics that the space produces to concentrate here and be reflected and scattered continuously. This phenomenon stirs the synaesthetic effect of aural and optical brightness as it combines the acoustic reflection with the visual reflection of light off the gold mosaics. As a result, the sonic brightness acts like a mirror reflecting the human vocal energy and in the process producing a radiant vision of the imagined splendor of the angelic choirs.[10] This luminous celestial voice is more prominent when the building is full. At these moments people and their clothing absorb most of the reflections off the polished surface of the floor. This process enhances the experience of an ephemeral concentration of sonic energy in the golden superstructure. In its volatile state, it quickly transforms into a golden sonic “rain.”[11] The semi-domes and the conches also produce the sensation of multiple waterfalls staggered at different times and places as they reach the listener. They contribute as well to the development of enveloping sound as they redirect and scatter the sound waves. While listening to sound under the dome is more uniform, further away from the dome the complexity of these staggered waterfalls acquires prominence.[12]

[1]Weitze, Rindel, Christensen, Gade, “The Acoustical History of Hagia Sophia revived through computer simulation,” and, site visited April 26, 2010. See also Weitze et al., CAHRISMAproject(Conservation of the Acoustical Heritage by Revival and Identification of the Sinan’s Mosque Acoustics),, site last accessed on April 9, 2009.

[2]Weitze, Rindel, Christensen, Gade, “The Acoustical History of Hagia Sophia revived through computer simulation;”E. Antoniades remarked on a special place in the soleawhere the reverberation was particularly prolonged, Antoniades, Ekphrasis tes Hagias Sophias, etoi melete synthetike kai analytike hypo apopsin architektoniken, archaiologiken kai historiken tou polythryletou temenous Konstantinoupoleos, 3 vols. (Leipzig: Teubner, 1907), I, 108. Shankland and Shankland, “Acoustics of St. Peter’s and Patriarchal Basilicas in Rome,” 392, 395.

[3]For a sound source in the apse, see the measurements released at, site accessed on April 26, 2010. For a sound source in the space under the dome (kallichoros), see Weitze, Rindel, Christensen, Gade, “The Acoustical History of Hagia Sophia revived through computer simulation.”

[4]Woszczyk, “Aural Architecture: Music, Acoustics, and Ritual,” 4.

[5]Beranek, Concert Halls and Opera Houses. Music, Acoustics and Architecture(Berlin/New York: Springer, 2004, 2nded.; 1st ed. 1996), 21, 29.

[6]The speech transmission index STI (0-completely unintelligible, 1-perfect intelligibility) is very low; a sound source set in the east end of the apse has poor intelligibility in the nave under the dome STI 0.3-0.4 and is unintelligible in the aisles and galleries, where STI is below 0.2; similarly the high T values (Center Time, time of the center of gravity of the squared impulse response) measured indicate poor clarity, see, site visited April 26, 2010.

[7]San Vitale offers a good comparison with respect to acoustics suited for monody, see D. Knight, “The Arcaeoacoustics of a Sixth-Century Christian Structure: San Vitale, Ravenna,” in Music & Ritual: Bridging Material and Living Cultures, ed. R. Jiménez, R. Till, and Mark Howell (Berlin: Ēchō Verlag, 2013), 133–46.

[8]Woszczyk, “Aural Architecture: Music, Acoustics, and Ritual,” 4.

[9]Woszczyk, “Aural Architecture: Music, Acoustics, and Ritual,” 4 and Moran,“The Choir of the Hagia Sophia,” 7. On the same acoustic effect produced by the dome of San Vitale, see Knight, “The Arcaeoacoustics of a Sixth-Century Christian Structure: San Vitale, Ravenna,” 136. For a general discussion of the acoustics of domes, see H. Kutruff, Room Acoustics(Oxon, UK: Spoon Press 2009; 5th ed.; 1st ed. 1973), 117-120, fig. 4.13.

[10]On the character of Hagia Sophia’s acoustics, see Abel, Woszczyk, D. Ko, S. Levine, J. Hong, T. Skare, M. Wilson, S. Coffin, F. Lopez-Lezcano, “Recreation of the acoustics of Hagia Sophia in Stanford’s Bing Concert Hall for the concert performance and recording of Cappella Romana,” presented at the International Symposium on Room Acoustics, Toronto, Canada, June 9-11, 2013,, 2–3, site accessed January 10, 2014; Woszczyk, “Aural Architecture: Music, Acoustics, and Ritual,” 4

[11]Woszczyk, “Aural Architecture: Music, Acoustics, and Ritual,” 4.

[12]Woszczyk, “Aural Architecture: Music, Acoustics, and Ritual,” 4.


Text and Figures excerpted from :
Pentcheva, Bissera, Hagia Sophia: Sound, Space, and Spirit in Byzantium (Pennsylvania State University Press, 2017), 102-4.