Sonic Heritage of Medieval Bells from the Valdres Region of Norway

Abstract

Bells have long been a defining feature of Christian culture, shaping the soundscapes of medieval Europe. This article examines the sonic heritage of active medieval bells in the Valdres region of Norway. We analyze the tonal structure of bells from Slidredomen, Lomen, Hegge, Reinli, and Hedalen churches based on acoustic measurements taken during fieldwork in the summer of 2024. We collected acoustic data using a Sound Level Meter Cesva 202 and a Zoom H4n recorder, which we then used for tonal analysis of the bells with Wavanal software. The results revealed the distinctive voices of individual bells while highlighting tonal similarities among certain bells and patterns in bell selection within specific churches. Based on the study’s valuable insights into the sound character of medieval bells in Valdres, we discussed medieval bell tuning and the implications for the preservation of medieval church bells as sonic heritage.

1. Introduction

The interdisciplinary field of sonic heritage focuses on documenting, analyzing, interpreting, and preserving sound as an important part of cultural heritage. Instead of just concentrating on physical remains, sonic heritage emphasizes the ephemeral, sensory, and often community-based experiences of soundscapes—ranging from everyday urban noise to ritual, musical, and environmental acoustics [1,2].

Research on sonic heritage reflects broad interdisciplinary interests, including acoustics, archeology, musicology, and heritage studies. The exploration of the sonic heritage of medieval sacred sites has become more popular over the last two decades, primarily through interdisciplinary archaeoacoustic studies [3,4,5] and acoustic heritage research [6,7,8,9], contextualizing the existing body of musicological research on Christian repertoires [10,11,12]. An inseparable part of medieval European soundscapes was the sound of church bells. Major research topics of the sonic heritage of medieval church bells involve the historical, liturgical, and material aspects of bells within medieval religious contexts [13,14], the cultural functions of medieval church bells and their role in constructing communal and political identities [15,16,17], as well as sound mapping of bell sound propagation across landscapes to demonstrate their ability to reach distant places [18,19,20].

Widely adopted across the Christian world in the late medieval period, church bell ringing resounded across European landscapes and played a vital role in connecting communities. Bells were not just used to mark time, call to prayer, or warn of danger; they also communicated messages about visits, deaths, celebrations, and other events. They symbolized the voice of God, ecclesiastical power, and governing authority, becoming characteristic sound marks in both urban and rural medieval Europe [21].

The powerful sound of church bells and the established ringing codes allowed immediate communication within the bells’ audible range, shaping distinctive acoustic communities. Consequently, the sounds of bells fostered a sense of unity, belonging, and connection to the wider religious landscape [22]. As historical artifacts, they also provide insight into the technological and cultural practices of their time. Their inscriptions reveal details about their commissioning, foundry, and dedication, while their design reflects advancements in medieval metalworking.

Beyond their physical characteristics, medieval bells are deeply intertwined with intangible cultural values. The UNESCO Convention for the Safeguarding of the Intangible Cultural Heritage [23] emphasizes that traditions, practices, and expressions passed down through generations are vital to cultural diversity and identity. Intangible cultural heritage includes oral traditions, performing arts, social practices, rituals, and traditional craftsmanship. Sonic heritage, which encompasses sound-related cultural expressions such as bell ringing, shapes communal identities and reinforces historical continuity. A notable example of this recognition occurred in 2024 with the inscription of Manual Bell Ringing on the Representative List of the Intangible Cultural Heritage of Humanity [24]. This designation encompasses both tangible and intangible elements, including bell-ringing techniques, bell shapes, acoustics, and bell towers. Rooted in medieval European traditions, manual bell ringing highlights the social and artistic importance of bells, serving both as musical instruments and means of communication. Although this Intangible Cultural Heritage inscription currently applies only to Spain and Italy, manual bell ringing has been a tradition in various European regions since the medieval period.

Sound plays an essential role in how past cultures and societies experience past and, therefore, can be considered key in cultural transmission [6,25]. Particularly, the ringing of bells is a sound mark, a unique auditory symbol characteristic of a specific area, spanning centuries and generations [14,26,27]. Medieval church bell ringing is one of the few musical sounds that have remained unchanged for a millennium [28]. The bells that rang for our medieval ancestors continue to resonate today, fostering a sense of continuity and belonging. Therefore, a church bell is “a unique object that serves as a natural symbol of a community’s identity” [29] (p. 73), and this sound mark “deserves to be protected … [because it makes] the acoustic life of a community unique” [30] (p. 10).

Price emphasized that a medieval bell has its own “voice” which “speaks to heaven and earth in a distinctive tone known to the whole community (for no bell sounded quite like any other), with the translation of this sound into words on its surface” [14] (p. 127). A recent “experiment” supports the uniqueness of the medieval bells’ voice. The live radio broadcast of A Very Large Concert featured ringing of over 200 bells from over ninety medieval churches across the island of Gotland in Sweden. Upon broadcasting this outstanding concert, listeners reported recognizing the distinct ringing of the bells from their village churches [31]. But, where does this uniqueness of the bell voice come from?

The distinctive sound of medieval bells may be attributed to the complexities of their tonal structures and the imperfections in tuning that existed before modern technological advancements. However, our understanding of medieval bell tuning theory and techniques remains limited. The 12th-century treatise The Art of the Metalworker by Theophilus Presbyter [32] describes the casting of large church bells in sufficient detail for an experienced founder to follow the lost-wax method [33]. Still, it does not provide rules for bell tuning. Further insight comes from Vincent de Beauvais, a Dominican friar at the Royaumont Abbey in France, who noted in the first half of the 13th century that three distinct tones might be identified in a bell: a low tone when struck at the middle, a high tone when struck at the upper waist, and an intermediate tone when struck at the lower waist [34]. However, this analytical observation of medieval bell sounds stands isolated in medieval history, leaving the bell as the primary piece of evidence of medieval bell tuning practice. In an effort to contribute to this field, this study explores the tonal structure of a selection of medieval bells preserved in the Valdres region of Norway.

Norway has an impressive collection of 264 still active medieval bells [35]. In this study, we focus on a selection of medieval bells found in the Valdres region. Acoustic data were collected during fieldwork in 2024 from ten medieval bells, dated in the 12th to 15th century, and housed in five churches: Slidredomen, a stone church, and four stave churches—Lomen, Hegge, Reinli, and Hedalen. By analyzing their tonal structure, we aim to determine whether each bell possesses a distinctive sound, i.e., a unique voice or they fit a tuning pattern. Thus, this article has three objectives:

• To document the tonal characteristics of medieval bells from Valdres;
• To explore possible medieval tuning practices;
• To discuss the cultural significance of medieval bells as carriers of medieval sonic heritage.

The article is organized into three main sections. First, we present the corpus of medieval bells and outline our research methodology. Second, we report our findings regarding the tonal structures of medieval bells in Valdres. Third, we discuss our study’s findings in the context of the possible medieval bell tuning aims and consider the implications for preserving these significant cultural artifacts. We emphasize the urgency of their safeguarding because they not only transmit fragments of medieval soundscapes but also serve as an enduring symbol of community identity. Finally, we conclude with key insights and recommendations for the future preservation of medieval bell heritage in the Valdres region and beyond.

2. Materials and Methods

2.1. Medieval Bells in the Valdres Region

The Valdres region is situated in central southern Norway, roughly in the middle of the area formed by Oslo, Bergen, and Trondheim (Figure 1). In Valdres, 23 medieval bells are noted [36]. For this study, we selected five churches that collectively have 12 medieval bells. Our selection criteria were that medieval bells are still regularly rung and available for acoustic testing, that we obtained permission from local community officials to ring them freely, and that they fit into the availability of our bell ringer.

The only church built in stone is Slidredomen, while the other four are stave churches—Lomen, Hegge, Reinli, and Hedalen. Each church houses bells in two locations: bell turret and campanile. A bell turret (in Norwegian takrytter, literally meaning “roof rider”) is a small turret-like structure on the ridge of a church roof, while a campanile (in Norwegian støpul) is a freestanding wooden bell tower separated from the main church building. Campanile has a stable structure with a broader ground floor than the upper one, allowing the housing of larger bells. It was historically constructed when the main church structure could not support the weight or the number of bells or when it was preferable to have the bells’ sound emanate from a different location.

Two shapes of bells were predominantly found in late medieval Europe. A Late Romanesque bell, also referred to as a sugarloaf-shaped bell, has an elongated form with a height greater than its mouth diameter, straighter sides, tapering steeply from the mouth to the crown. It was produced between the 12th and 14th centuries. Since the 14th century, a Gothic bell profile has gradually emerged, characterized by a more emphasized bell waist and shoulder, as well as a smaller height-to-diameter ratio. These two shapes are also noted in medieval bells from Valdres. This difference in bell profiles is evident in Figure 2, which displays medieval bells from Hedalen church—HED01, a sugarloaf-shaped bell, and HED02, with an early Gothic profile.

All the bells we examined in Valdres are still rung manually. Aware of the traditional manual bell ringing—a practice inscribed on the UNESCO Representative List of the Intangible Cultural Heritage of Humanity in 2024 [24], we were guided by Henning Andersen, a professional bell ringer with over 30 years of experience. Residing in the region, he possesses invaluable knowledge of the local bell heritage and the history of bell ringing. Besides being our guide, he also rang all the bells we recorded.

The Slidredomen is a stone parish church that houses five medieval bells. Four (SL01-04) are in the bell turret atop the church, and one (SL05) is in the wooden campanile on the hill across the road (Figure 3). According to Henning Andersen, the bell SL01 has casting errors visible on the irregular exterior surface, while the bell SL03 cracked about 20 years ago and has been welded. Bell SL04 has a longer sound bow than the other three bells in the church tower. Bell SL05, located in the campanile built in 1679, is excluded from this study due to the reduced quality of the recordings.

The Lomen stave church was constructed at the end of the 12th century and expanded in the mid-18th century. It is occasionally used during the summer months, as it ceased to serve as the parish church when the new Lomen Church was consecrated in 1914 and took over the parish church role [38] (p. 112). The campanile, constructed in 1771 on the eastern side of the main church, houses two medieval bells—LO01 with a sugarloaf profile, from the mid-12th century, and LO02 with an early Gothic profile, from the mid-14th century (Figure 4).

The Hegge stave church is located on a mountainside in the northernmost part of Valdres. It was built in the 13th century and underwent several alterations in the 19th century [38] (p. 106). It still serves as a parish church. The campanile, situated in front of the main entrance to the church (on its northwest side), houses four bells, two of which are medieval (Figure 5). One of the medieval bells (HEG02 in

Table 1. Medieval bells in the Valdres region, examined during the archaeoacoustic fieldwork in August 2024.

Church (Century of Building) 1	Medieval Bells ID	Position of Bells	Approximate Dating of Bells 2	Size of Bells [cm] Outer Diameter/Height + Crown
Slidredomen church 12th c.	SL01	Bell turret	Mid-14th-mid-15th c.	60/53 + 10
	SL02	Bell turret	First half of the 13th c.	61/55 + 17
	SL03	Bell turret	First half of the 13th c.	58/56 + 18
	SL04	Bell turret	Mid-14th c.	54/50 + 10
	SL05	Campanile	n/a	90/77 + 18
Lomen stave church End of 12th c.	LO01	Campanile	Mid-12th c.	n/a
	LO02	Campanile	Mid-14th c.	n/a
Hegge stave church 13th c.	HEG01	Campanile	12th c.	49/n/a
	HEG02	Campanile	13th c.	47.5/n/a
Reinli stave church 13–14th c.	RE01	Campanile	n/a	n/a
Hedalen stave church Mid-13th c.	HED01	Bell turret	Mid-12th c.	46/43 + 15
	HED02	Campanile	14th c.	63/56 + n/a

¹ The abbreviation ‘c.’ denotes ‘century’. ² The approximate dating of the bells is given by Henning Andersen (www.kyrkjeklokker.no accessed on 15 March 2025), professional bell ringer from the region. The Norwegian Institute for Cultural Heritage Research (NIKU) has a database of medieval bells, possibly with dating, but it was not available during our research 2024/2025.

) has a detached clapper, so we did not record any swings. Therefore, this bell is excluded from further tonal analysis. Both bells were originally located in the Lidar stave church, which was approximately 6 km away from the Hegge stave church and was demolished in the 17th century.

The Reinli stave church was constructed on the site of an older sanctuary atop a hill, offering a fantastic view of Begnadalen valley. Built in the early 14th century and reconstructed in the 17th and 18th centuries, it has remained unchanged in its original form. The church’s campanile, built in the mid-19th century to replace an older structure, houses a sugarloaf-shaped bell from the 14th century (RE01 in Figure 6).

The Hedalen stave church is located in a remote village in the Valdres region. It was built in the late 12th century. Initially, the church had a nave and a chancel, representing the most common type of construction in the early years of Norway’s Christianization [38] (p. 98). At the end of the 17th century, it was expanded into a cruciform church. The church has two active medieval bells—one in the bell turret and the other in the campanile. The latter has an inscription “NICOLAVS ANGELVS ME FECIT,” translated as “Nicolaus the Englishman made me.” This bell HED02 has an early Gothic profile with more emphasized curve in comparison to earlier Late Romanesque or sugarloaf profiles that are more elongated, such as HED01 (Figure 7b). The production of bells with Gothic profiles started in the 14th century. In the 14th century, when church bells were frequently traded between England and Norway [39]. Henning Andersen states that the sound of this bell is up to “the ideals of the time” [40].

2.2. Archaeoacoustic Methods

The methodology used in this archaeoacoustic study has three main parts: (1) fieldwork acoustic measurements, (2) post-processing of bell recordings, and (3) tonal analysis of recorded bells.

2.2.1. Fieldwork Acoustic Measurements

The archaeoacoustic fieldwork was conducted in mid-August 2024 in the Valdres region. We examined a total of 12 medieval bells found in five churches presented in Section 2.1: Slidredomen, Lomen, Hegge, Reinli, and Hedalen churches.

The acoustic procedure involved taking measurements with a Sound Level Meter Cesva 202 connected to a Zoom H4n recorder, providing, for each recording, the measured sound pressure levels in an Excel file along with the corresponding audio file in WAV format. The format used for these recordings is uncompressed audio, specifically in WAV 24-bit stereo with a quantization sample rate of 48 kHz. At each site, recordings were made from various positions to capture a broad range of distances from the bells. This included at least three positions: inside the bell tower, outside in the immediate vicinity of the church, and outside at a distance of at least 50 m from the church. The exact positions varied depending on the terrain and the available space within the towers.

In the near-field measurements taken inside the bell tower, each bell was recorded from a distance of 1 to 1.2 m from the bell’s sound bow. The available space in a bell turret or campanile, as well as the height of the bell above the floor, influenced the distance for placing the sound level meter mounted on a tripod and the height of the bell. For the outside positions sound level meter were set looking at the church at a height of 1.5 m, the average ear height of a standing person.

All bells were rung manually by the professional bell ringer and our invaluable guide in this fieldwork, Henning Andersen. Our recordings included three ringing patterns: three successive claps with the clapper moved directly by hand, a bell swing performed by pulling the rope, and, in cases where more than one bell is placed in the same space, we recorded how these bells sound when swinging together by professional bell ringers.

For the tonal analysis in this article, we only used recordings of bell swings, performed by pulling the rope attached to the yoke, captured near the bell in the bell turret or campanile. The full dataset, which includes all measurement positions and bell ringing patterns, as well as the post-processed files of one isolated swing, is available at https://doi.org/10.34810/data2255.

2.2.2. Post-Processing of Bell Recordings

In the post-processing phase, a four-step procedure was followed to prepare the recordings for the tonal analysis. In this phase, we included stereo recordings of bell swings because they are more reproducible than bell claps; during swings, the yoke consistently moves in the same manner around a fixed horizontal axis. In contrast, when striking the bell manually (by clapping the bell), the sound significantly varies with the strike point, the clapper used, and the strength applied [41].

Selected files were prepared for the audio analysis by using freely available software Audacity, version 2.4.1 (Audacity Team. Audacity Software 2.4.1; Audacity Team: Pittsburg, PA, USA, 2019). First, we selected bell recordings with the highest level and minimal overlap between the last swing and the previous one. Then we isolated the final swing and applied a high-pass filter to reduce low-frequency noise (below 50 Hz). Each normalized mono signal was then exported in WAV format with a quantization sample rate of 48 kHz and a 16-bit depth.

2.2.3. Tonal Analysis of Bells

The files obtained in the post-processing phase were further used for analysis in the Wavanal software, version 5.10 [42]. This free-licensed software tool is designed for analyzing bell tuning using recorded sound. It identifies the partial frequencies and harmonic character of a bell.

3. Results: Tonal Structure of Medieval Bells from Valdres

Vibrating in a complex, three-dimensional way, bells produce rich, musical sounds composed of numerous individual frequencies, known as partial frequencies or partials [43]. The theoretical framework that we use for assessing the tuning of medieval bells from Valdres is True Harmonic Tuning (THT). This method of tuning bells implies that their key partials align with harmonic musical intervals, producing a more musically pleasing sound, particularly when played in a set. All partials can be expressed as frequencies (in Hertz), musical notes, or deviations from a reference note (nominal partial), measured in cents. A cent is a unit of measurement used to indicate slight differences in pitch between two tones. Given that one semitone has 100 cents in the 12-tone equal temperament tuning system, cents enable precise frequency comparisons, particularly in analyzing a complex inharmonic spectrum, such as that of bells. Five key partials in bell tuning—hum, prime, tierce, quint, and nominal—are typically tuned to specific pitches relative to the nominal (

Table 2. The relationship between essential partials, musical intervals, and their deviation from the nominal note in cents, according to the theory of True Harmonic Tuning.

Partial	Musical Interval	Interval in Cents
Hum	Two octaves below nominal	−2400
Prime	One octave below nominal	−1200
Tierce	Minor third above prime	−900
Quint	Perfect fifth above prime	−500
Nominal	Unison	0

). Unlike most strings or wind musical instruments, the partials of a bell usually do not correspond to whole-number ratios of the fundamental frequency. This means that the relationships between bell tones must be measured in cents rather than simple harmonic ratios.

We recorded 12 medieval bells in Valdres. However, two recordings were discarded in the post-processing phase: SL05 and HEG02. The latter bell had a detached clapper, which prevented us from recording the bell swing. In the case of SL05, the low signal-to-noise ratio of the recording makes this file of insufficient quality to be analyzed with Wavanal software tool.

The analysis performed with the Wavanal software tool revealed the spectral position of the first five partials for half of the examined bells only (colored columns in

Table 3. Comparison of the pitch of the first five partials in the True Harmonic Tuning (THT) and the examined bells, relative to their respective nominal pitches in cents. For each examined bell, the deviation of its nominal pitch from the THT nominal is shown in the row ‘True nominal’. Colored columns highlight the bells for which Wavanal identified the first five partials.

PARTIAL	MEDIEVAL BELLS IN VALDRES
	THT	SL01	SL02	SL03	SL04	LO01	LO02	HEG01	RE01	HED01	HED02
Hum	−2400	−2424	−2676	−2600	−2696	−2168	−2219	−2674	−2497	−2531	−2437
Prime	−1200	−1472	−1390	−1024	−1216	−1450	−1449	−1223	−1056	−1435	−1525
Tierce	−900	−921	−970	−877	−980	−816	−894	−972	−778	−886	−950
Quint	−500	−597	−840	−760	−653	−561	−236	−712	−648	−729	−555
Nominal	0	0	0	0	0	0	0	0	0	0	0
True nominal	0	1298	1553	1200	1367	2330	1216	2039	1303	1987	1829

and

Table 4. Acoustic and musical analysis of the first five partials of the Valdres bells, including measured frequencies and corresponding musical notes (±cents) as identified using Wavanal; the ideal and closest musical intervals relative to the prime partial; harmonicity based on proximity to simple frequency ratios; and an assessment of perceived consonance or dissonance. Colored rows mark the bells for which Wavanal identified the first five partials.

BELL	Partial	Frequency (Hz)	Musical Note +/− Cents	Ideal Musical Interval (Fr. Ratio to Prime)	Closest Musical Interval (Fr. Ratio to Prime)	Harmonicity (Closest Integer Ratio)	Consonance
	Hum	320	Eb(4) + 49	Octave below (0.5)	Minor seventh below prime (0.577)	Inharmonic	Mild dissonance
	Prime	554.5	Db(5) + 0	Unison	Unison	Reference	Reference
SL01	Tierce	762.5	G(5) − 47	Minor third (1.2)	Augmented fourth (1.375)	Midly harmonic (11:8)	Mild dissonance
	Quint	919.5	Bb(5) − 23	Perfect fifth (1.5)	Major sixth (1.658)	Harmonic (5:3)	Soft consonance
	Nominal	1298	E(6) − 26	Octave (2.0)	Octave + minor third (2.340)	Mildly harmonic	Soft consonance
	Hum	331	E(4) + 10	Octave below (0.5)	Major 7th below prime (0.476)	Inharmonic	Sharp dissonance
	Prime	695	F(5) − 8	Unison	Unison	Reference	Reference
SL02	Tierce	886.5	A(5) + 13	Minor third (1.2)	Major third (1.276)	Mildly inharmonic	Soft consonance
	Quint	954.5	Bb(5) + 41	Perfect fifth (1.5)	Perfect fourth (1.373)	Harmonic (11:8)	Soft consonance
	Nominal	1553.5	G(6) − 15	Octave (2.0)	Octave + major second (2.235)	Midly harmonic (9:4)	Mild dissonance
	Hum	267	C(4) + 35	Octave below (0.5)	Octave + major third below prime (0.402)	Mildly harmonic (2:5)	Soft consonance
	Prime	664.5	E(5) + 14	Unison	Unison	Reference	Reference
SL03	Tierce	723	F#(5) − 39	Minor third (1.2)	Major second (1.088)	Inharmonic	Mild dissonance
	Quint	773.5	G(5) − 22	Perfect fifth (1.5)	Minor third (1.164)	Inharmonic	Soft consonance
	Nominal	1200	D(6) + 37	Octave (2.0)	Major seventh (1.806)	Mildly harmonic (9:5)	Sharp dissonance
	Hum	288.5	D(4) − 30	Octave below (0.5)	Octave + major second below prime (0.426)	Mildly inharmonic	Mild dissonance
	Prime	677.5	E(5) + 47	Unison	Unison	Reference	Reference
SL04	Tierce	775.5	G(5) − 18	Minor third (1.2)	Minor third (1.145)	Inharmonic	Soft consonance
	Quint	937.5	Bb(5) + 10	Perfect fifth (1.5)	Diminished fifth (1.384)	Mildly harmonic	Sharp dissonance
	Nominal	1367	F(6) − 36	Octave (2.0)	Octave + 17 cents (2.018)	Mildly inharmonic	Soft consonance
	Hum	666	E(5) + 18	Octave below (0.5)	Perfect fifth below prime (0.660)	Mildly harmonic (2:3)	Open consonance
	Prime	1008.5	B(5) + 36	Unison	Unison	Reference	Reference
LO01	Tierce	1454	F#(6) + 30	Minor third (1.2)	Perfect fifth (1.442)	Mildly inharmonic (7:5)	Open consonance
	Quint	1685	Ab(6) + 25	Perfect fifth (1.5)	Minor seventh (1.671)	Mildly harmonic (5:3)	Mild dissonance
	Nominal	2330.5	D(7) − 13	Octave (2.0)	Octave + minor third (2.311)	Mildly inharmonic	Soft consonance
	Hum	337.5	E(4) + 41	Octave below (0.5)	Minor sixth below prime (0.641)	Mildly inharmonic (5:8)	Soft consonance
	Prime	526.5	C(5) + 11	Unison	Unison	Reference	Reference
LO02	Tierce	725.5	F#(5) − 33	Minor third (1.2)	Augmented fourth (1.378)	Mildly harmonic (11:8)	Sharp dissonance
	Quint	1060.5	C(6) + 23	Perfect fifth (1.5)	Octave (2.015)	Harmonic (sharp)	Open consonance
	Nominal	1216	Eb(6) − 39	Octave (2.0)	Octave + minor third (2.310)	Mildly inharmonic (7:3)	Soft consonance
	Hum	435.5	A(4) − 17	Octave below (0.5)	Octave + major second below prime (0.433)	Mildly inharmonic (7:16)	Mild dissonance
	Prime	1006.5	B(5) + 33	Unison	Unison	Reference	Reference
HEG01	Tierce	1163.5	D(6) − 16	Minor third (1.2)	Minor third (1.156)	Inharmonic	Soft consonance
	Quint	1351.5	E(6) + 43	Perfect fifth (1.5)	Perfect fourth (1.343)	Harmonic (4:3)	Open consonance
	Nominal	2039.5	C(7) − 44	Octave (2.0)	Octave + 23 cents (2.026)	Mildly inharmonic	Soft consonance
	Hum	308	Eb(4) − 16	Octave below (0.5)	Octave + major second below prime (0.435)	Inharmonic	Mild dissonance
	Prime	708.5	F(5) + 25	Unison	Unison	Reference	Reference
RE01	Tierce	813.5	Ab(5) + 2	Minor third (1.2)	Minor third (1.148)	Inharmonic	Soft consonance
	Quint	896	A(5) + 31	Perfect fifth (1.5)	Major third (1.264)	Mildly Inharmonic	Soft consonance
	Nominal	1303	E(6) − 19	Octave (2.0)	Major seventh (1.839)	Mildly Inharmonic	Sharp dissonance
	Hum	460.5	Bb(4) − 20	Octave below (0.5)	Major seventh (0.531)	Mildly inharmonic (1:2)	Sharp dissonance
	Prime	867.5	A(5) − 24	Unison	Unison	Reference	Reference
HED01	Tierce	1191	D(6) + 24	Minor third (1.2)	Perfect fourth (1.373)	Mildly harmonic	Open consonance
	Quint	1304	E(6) − 18	Perfect fifth (1.5)	Perfect fifth (1.502)	Harmonic (3:2)	Open consonance
	Nominal	1987	B(6) + 10	Octave (2.0)	Octave + major second (2.290)	Mildly inharmonic	Mild dissonance
	Hum	315.5	Eb(4) + 24	Octave below (0.5)	Minor sixth below prime (0.590)	Mildly inharmonic	Soft consonance
	Prime	534.5	C(5) + 37	Unison	Unison	Reference	Reference
HED02	Tierce	745	F#(5) + 12	Minor third (1.2)	Augmented fourth (1.394)	Inharmonic	Sharp dissonance
	Quint	936	Bb(5) + 7	Perfect fifth (1.5)	Minor seventh (1.751)	Inharmonic	Mild dissonance
	Nominal	1289.5	E(6) − 38	Octave (2.0)	Octave + major third (2.412)	Mildly inharmonic (12:5)	Soft consonance

), leaving the main partials of the other five bells unidentified. As noted in the software manual, the failure to name the main partials might be due to the hum being too quiet [42]. Therefore, we manually identified the most probable first five partials for the following bells SL02, SL03, SL04, HEG01, and RE01.

Table 3 presents five partials of the examined bells in centselative to the nominal. This approach enables comparisons in tuning among the medieval bells and with the standards established by the THT. While some bells, like SL01, LO01, and HED02, show a similar distribution of partials relative to the THT, others differ significantly. Across the examined bells, the prime partial varies from −1525 to −1024 cents, spanning about five semitones of the equal-tempered scale, which corresponds to a musical interval of a perfect fourth.

To offer a better understanding of Valdres bells’ tonal characteristics, Table 4 presents acoustic and musical analysis of the first five partials of the Valdres bells. The table includes measured frequencies (Hz) and corresponding musical notes from the equal-tempered scale (±cents) as identified using Wavanal (A4 = 440 Hz). To explore the harmonicity and consonance of bells, this table also includes the ideal and closest musical intervals relative to the prime partial, as well as the frequency ratio of a partial to the prime.

Harmonicity is an acoustic property of sound. It refers to how closely a partial aligns with simple whole-number frequency ratios (such as 2:1, 3:4, 5:3) within the harmonic series. This alignment often contributes to a sense of clarity, tonal stability, or pleasantness. Harmonic sounds—like those produced by a violin or flute—have partials that correspond to these ratios, while inharmonic sounds—like those made by bells—deviate from them. Although harmonicity is generally associated with musical pleasantness, a certain degree of inharmonicity can enrich the sound, especially in ritual contexts where brightness or tension may be desirable. To describe the harmonicity of Valdres bells, we used four categories:

▪

Harmonic—a whole-number frequency ratio;

▪

Mildly harmonic—not exact whole-number frequency ratio, but still close enough to sound consonant;

▪

Mildly inharmonic—deviates from a whole-number frequency ratio and begins to sound noticeably off, though not severely dissonant;

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Inharmonic—deviates significantly from an ideal harmonic ratio, often resulting in perceptible dissonance.

In addition to harmonicity, which is an acoustic property of sound, we also looked into the perceptual experience of pleasantness, stability, or smoothness when two or more sounds are heard together. While high harmonicity often leads to perceived consonance and inharmonic intervals usually produce dissonance, some mildly inharmonic intervals can still sound consonant, depending on the cultural and social context. Thus, bells often contain inharmonic partials but are not necessarily perceived as unpleasant. In the musical analysis of Valdres bells, we use the following qualitative scale of consonance and dissonance, based on Vincent Persichetti’s classification [44] (p. 14):

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Open consonance—octave, perfect fifth—sound pure and stable;

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Soft consonance—major/minor third, major/minor sixth—still sounds pleasant, but with mild tension;

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Mild dissonance—major second, minor seventh—sound tense or unstable;

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Sharp dissonance—minor second, major seventh, tritone (augmented fourth/diminished fifth)—sounds highly tense, biting, piercing;

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Exception—perfect fourth (can be considered consonant in dissonant surroundings and dissonant in consonant surroundings).

The bell turret of the Slidredomen church houses four medieval bells with varying levels of harmonicity. The bell SL01 is mostly harmonic, balancing consonant quint and nominal partials with more expressive dissonance in the tierce and hum partials. This bell gives a balanced yet rich timbre. The bell SL02 has a generally harmonic structure, anchored by a consonant tierce and quint partials, which provides strong tonal stability. In addition to this pleasing core stability, peripheral tension is created with the inharmonic and sharply dissonant hum partial and the mildly dissonant nominal. The bell SL03 displays a slightly unstable tonal character with some harmonic grounding in its consonant hum and quint partials, along with a less stable tierce and sharply dissonant nominal. The reason for the tonal instability of SL03 might lie in the fact that the bell cracked and was subsequently welded about twenty years ago. The bell SL04 produces a somewhat rough but stable timber. Its mildly inharmonic and mildly dissonant hum gives a dark undertone, while the tierce—a softly consonant minor third—sits close to its ideal tuning of THT. The quint forms a mildly harmonic and dissonant diminished fifth, and the nominal—nearly a pure octave—is softly consonant, helping to stabilize the bell’s overall sound. Among the four Slidredomen bells, SL04 aligns most closely with the theoretical THT model.

When the four medieval bells from Slidredomen are heard together, they offer a compelling blend of harmonic clarity and expressive color, despite their markedly different nominal pitches (see Table 2, True Nominal). SL01 and SL02 provide the most consonant core, primarily through their strong quint partials, while SL03 and SL04 introduce more complex textures and nuanced dissonance.

The campanile of the Lomen stave church houses two medieval bells with contrasting harmonic profiles. Bell LO01 has a relatively consonant spectrum, featuring a mildly harmonic hum partial forming a consonant perfect fifth below the prime, and a mildly inharmonic but still consonant tierce. Its quint is mildly harmonic and dissonant, forming a minor seventh, while the nominal is mildly inharmonic and softly consonant. Bell LO02, in contrast, displays a more varied structure: its hum partial is mildly inharmonic and softly consonant, the tierce forms a sharply dissonant augmented fourth, and the quint is sharply tuned but harmonic, producing an openly consonant octave. Its nominal is mildly inharmonic and softly consonant. Together, the two bells offer a rich and complementary timbral texture. LO01 yields clarity and tonal stability, while LO02 introduces more spectral tension, resulting in a complex but balanced acoustic pairing.

In Hegge stave church, bell HEG01 exhibits a moderately stable harmonic profile. The hum partial is mildly inharmonic and mildly dissonant, falling an octave and major second below the prime. The tierce forms an inharmonic but softly consonant minor third, while the quint is harmonically strong, forming an openly consonant perfect fourth. The nominal is only mildly inharmonic, very close to the ideal octave, and provides a stabilizing anchor to the upper spectrum, contributing to a focused and coherent tonal structure despite minor imperfections in the inner partials.

Bell RE01 displays a moderately stable harmonic profile. The tierce and quint partials, though slightly inharmonic, form softly consonant intervals with the prime, contributing to a coherent core structure. The hum partial is inharmonic and mildly dissonant, introducing some roughness to the lower end of the spectrum. The nominal forms a major seventh with the prime, which is mildly inharmonic and sharply dissonant, thus destabilizing the upper harmonic profile. Overall, the bell RE01 has a moderately consonant center with tension at the spectral extremes.

Hedalen stave church houses two medieval bells—HED01 in bell turret and HED02 in the campanile. Bell HED01 presents a largely dissonant profile. The tierce and quint form perfect fourth and perfect fifth with the prime partial, establishing a strong tonal core. The hum partial is mildly inharmonic and sharply dissonant, adding low-end tension. The nominal is mildly inharmonic and forms an octave plus major second with the prime, which is mildly dissonant, softening the clarity of the upper spectrum. In contrast to HED01, the bell HED02 exhibits inharmonicity in the inner partials. The tierce and quint deviate from simple frequency ratios, resulting in sharp to mild dissonance across the middle spectrum. The hum and nominal are mildly inharmonic with softly consonant interval, contributing some tonal focus to the bell’s upper range. Overall, the bell HED01 is well balanced, with a strong harmonic center and spectral instability at the extremes, while the bell HED02 displays a complex and slightly rough harmonic structure, with a degree of spectral anchoring provided by the hum and nominal. Together, these two bells may produce a texturally rich but slightly tense blend. HED01 offers clarity and tonal focus, while HED02 produces a denser, more complex timbre. Their combined sound likely reflects a contrast between harmonic stability and spectral tension, enhancing auditory interest while maintaining overall cohesion. Since they are located in different spaces—one in the bell turret and the other in the campanile—their sounds reach the listener with slight spatial and temporal separation, influencing their blending and contributing to a layered soundscape rather than a unified, focused bell tone.

When considering all ten bells from Valdres together, a pattern of mild inharmonicity emerges, particularly in the tierce, quint, and nominal partials. Despite these deviations from ideal harmonic ratios, many intervals remain mildly or moderately consonant, contributing to a cohesive and recognizable bell sound. This indicates a tradition in which perfect harmonicity was not essential and minor tuning imperfections were acceptable—perhaps even valued—for their contribution to acoustic richness and character.

In churches that house multiple bells, such as Slidredomen, Lomen, and Hedalen, the bells often display complementary spectral characteristics. Pairs like SL01–SL04, LO01–LO02, and HED01–HED02 exhibit a balance in their partial structures: one bell typically offers greater harmonic stability, while the other introduces spectral tension through more inharmonic or dissonant intervals. This contrast may enhance the textural complexity and dynamic layering of the overall soundscape when the bells are rung together.

During the ringing of the bell, prominent partials appear. Additionally, the level of a bell’s partials varies over time, sometimes fading away completely and then reappearing. These temporal characteristics of a bell’s sound are not represented in the Wavanal analysis, which only reports the presence of partials regardless of their energy fluctuations. Figure 8 shows the spectrogram and waterfall diagram of the recorded signal of the bell SL01 to illustrate the energy distribution across time and frequency. In both plots, the color scale represents the signal’s amplitude in dB at each point, highlighting the temporal variations in the level of each partial. It can be observed that the first three partials have a longer duration, with the hum tone (330 Hz) outliving all other partials, lasting more than twice as long as the tierce (762.5 Hz). At higher frequencies, including the prime (554.5 Hz), the sound fades away significantly earlier. It is worth noting that, although the perceived pitch of the bell is typically linked to the prime partial, this example shows that this partial is not always the one with the most significant amplitude.

4. Discussion

4.1. Rediscovering Medieval Bell Tuning

The first reported attempt to tune the partial frequencies of bells is attributed to the collaboration between Jacob van Eyck (1590–1657) and the Hemony brothers on a commission for carillon bells. Regarding the principles of Hemony tuning, Herman von Helmholtz (1821–1894), a German physicist and physician, in his book Sensations of Tone, wrote that “Hemony of Zutphen, a master in the seventeenth century, required a good bell to have three Octaves, two Fifths, one major and one minor Third” [45] (p. 72). Following these 17th-century breakthroughs, knowledge of bell tuning was gradually lost. However, it was recovered at the end of the 19th century, thanks to the collaboration of Canon Arthur Barwick Simpson and the John Taylor & Co bell foundry in England, when Simpson proposed a method of tuning similar to the Hemony process [46,47].

In 1895, Simpson published a bell tuning theory in which the presence of multiple strong partials is essential for a harmonious bell sound. He wrote: “Every true bell should give out, when fairly struck, a fundamental note or ‘tonic,’ its third, fifth, and octave above, and its octave below, thus sounding the full chord–do, mi, sol, do, with the bass do below. (…) three [partials] would sound the same note, in three consecutive octaves, and the bell would, so far, be “in tune with itself” [46]. John William Taylor (1827–1906) utilized Simpson’s ideas to develop a tuning method that ensured the most prominent partials of a bell aligned harmoniously. Thus, Simpson’s insights laid the groundwork for what became known as True Harmonic Tuning (THT)—a method of tuning bells so that their key partials align with harmonic musical intervals, producing a more musically pleasing sound, particularly when played in a set.

Since the knowledge of harmonious bell tuning was rediscovered two centuries after it fell into obscurity following the achievements of the Hemony brothers in the 17th century, it is reasonable to assume that the bell founders who preceded them, including those from the medieval period, may have practiced specific bell-tuning techniques. In his second paper, Simpson stated that if he were a bell founder, he would have kept any special knowledge to himself and used it to his own advantage [47]. He also highlighted that at the end of the 19th century, bell tuners would select either the nominal or prime note for tuning, leaving other partials untuned. Specifically, English bell founders tended to tune the nominals, while primes were tuned in other parts of Europe, neglecting other partials [46].

Although no medieval documents on bell tuning have reached our time, the complexity of bell sounds certainly posed a challenge for medieval bell founders. To reveal medieval bell tuning practices, we must understand what bell founders sought in tuning a church bell. In this section, we will further discuss three main points that may illuminate medieval bell tuning: (1) What is a bell strike note? (2) What elements influence the perception of bell sounds? And finally, (3) how can the tonal analysis of medieval bells from Norway contribute to this quest of revealing medieval bell tuning practices?

The strike note is the pitch we hear when a bell rings. It is a perceived note. In the 1970s, Ernst Terhardt formulated the Virtual pitch theory in psychoacoustics. This theory shows how the ear reconstructs missing fundamentals in complex tones, thus explaining why bells have a perceived pitch even though their physical vibrations do not conform to standard harmonic partials [48]. A bell pitch is a subjective tone produced by three nearly harmonic partials: the prime, quint, and nominal. Most listeners perceive the metallic strike note as having a pitch at or near the prime, while others interpret the pitch as an octave higher. These prominent partials dominate the strike tone, while many inharmonic partials decay rapidly. As the bell’s sound fades, a slowly decaying hum tone, an octave below the prime, continues to resonate [43], as illustrated in Figure 8. Listeners usually describe the strike note of a European church bell as the prime, heavily influenced by the frequencies of the fifth partial (which is nominal), as well as the following sixth partial (superquint, expected to be a twelfth above the prime in modern tuning) and seventh partial (octave nominal expected to be two octaves above the prime in modern tuning) [49] (p. 683). This perception of the bell’s complex sound relies on the listener’s focus on individual partials, which can change depending on the clapper and the force of the strike [50]. In addition, it has been demonstrated that listeners can detect frequency changes in bell sounds within a range of ten to fifteen cents [51].

Several other elements are documented to affect the perception of bell sounds. One of the critical measures of bell sound quality is the energy in the first five partials [52]. Another defining factor is acoustic beating, which occurs when two comparable partials are very close to each other in the spectrum. This phenomenon does not affect the perception of bell pitch but defines the overall impression of the bell’s sound quality.

It has been demonstrated that the sound of a bell depends not only on its physical characteristics but also on various parameters, such as the ringing angle, bell tower, and the dynamic system of the bell, yoke, and clapper. The design of the clapper has proven to be particularly crucial for the sound quality of bells, as the high-frequency partials are determined by the clapper’s mass (the lower it is, the brighter the sound). In addition, the weight and approach speed of the clapper primarily influence the low-frequency partials. The strike’s duration is becoming increasingly significant in optimizing the sound behavior of a ringing bell [53].

All these findings suggest that the subjective experience of bell sounds depends on many factors: its spectral structure, the amount of energy in the first five partials, the clapper, etc. Therefore, the acoustic examination of medieval bells must be supplemented with subjective listening tests that include trained bell ringing and authentic medieval bells with clappers to understand the strike note that medieval bell founders aimed for in each bell. Medieval bells from Norway can significantly contribute to this research for at least two reasons. First, Norway has 264 active medieval bells, representing a substantial sample that allows for a detailed investigation of medieval bell tuning practices. Second, the manual bell-ringing practice is still maintained and transmitted from generation to generation. The skilled carriers of the bell-ringing tradition can swing multiple bells at a time. They feel their bells and know how to ring them differently depending on the occasion, message, and emotion they want to transmit to the congregation. Such a setting, with authentic medieval bells, churches, and skilled bell-ringers, presents a unique opportunity to undertake listening tests to better understand the sounds of medieval church bells.

The final question to discuss is how the tonal analysis of medieval bells from Valdres can contribute to revealing medieval bell tuning practices. Our study’s results, presented in Section 3, revealed a pattern of mild inharmonicity across medieval bells in Valdres, thus indicating that minor tuning imperfections were acceptable and possibly even valued as they provide a uniqueness of a bell’s voice. Furthermore, the tonal analysis revealed that churches in the Valdres region house bells with complementary spectral characteristics, where one bell exhibits harmonic stability while the other offers spectral tension through more dissonant intervals.

Lehr argues that the free choice of bell tonal structure did not exist in the medieval period. Although medieval bells have a wayward, loudly sounding minor-third interval that “strongly influences the character of the bell and by tradition is considered the characteristic partial of the bell,” it results from the profile curve already set in the Middle Ages [34] (pp. 15, 27). Out of the ten Valdres bells examined, a minor third interval is detected between the prime and the tierce in three bells (SL04, HEG01, RE01), and between the prime and the quint in one bell (SL03). In the latter case, this is mainly due to the prime frequency being significantly higher—relative to the frequency distribution of the other partials—than in the other bells considered in this study. This could happen as a result of welding the SL03 bell after cracking. Based on the Valdres sample of medieval bells used in our study, the minor third interval does not occur as a rule.

The bells were heard both in the church and across the landscape. The hum partial might hold a specific importance for the listener inside a church, as Simpson [47] illustrated:

“Sitting in my dining room, with outer and inner doors shut, I was struck by the singularly sweet sound of our six little Fittleworth bells as heard down the chimney. On opening the doors so as to hear them directly, I observed with surprise that the scale was different, and I finally discovered that what I had heard down the chimney were the hum-notes, which alone found their way to me by this devious course. After this experience, we cannot dismiss the hum-notes as unworthy of careful attention.”

This illustration is significant when considering that the bell turret—a tower in which bells are mounted—is located atop the church, high above the nave, and has a form very similar to that of a chimney. According to Simpson, down the chimney, the hum notes are dominantly heard. Therefore, we can assume that the hum notes prevail over the bell sounds in the church nave where the religious service is taking place.

Finally, it is interesting to note that five of ten examined bells have hum around the E note (E(4) in SL02, LO02; E(5) in LO01; and Eb(4) in SL01, RE01, and HED02). This brings us back to Simpson’s observation that bell tuners at the end of the 19th century selected either the nominal or prime note for tuning, leaving other partials untuned [46]. Could it be, then, that medieval bell tuners tuned only the hum note?

4.2. Medieval Bells as Sonic Heritage: Implications for Heritage Preservation and Community Identity

Churches, churchyards with their enclosures, and church inventories in Norway dating before 1537 AD are nationally protected under the Cultural Heritage Act. While this Act includes medieval bells, it does not extend to bell ringers, who serve as the carriers of bell-ringing traditions and a crucial link to the sonic heritage of these bells. The Valdres region has preserved the practice of manual bell ringing, and during our fieldwork, we had the honor of witnessing the joint performance of two bell ringers in Slidredomen. This remarkable tradition, however, is at risk of extinction as electrified bell-ringing systems are increasingly replacing manual ringing. Before we lose professional bell ringers—some of whom have mastered their skills for over fifty years—it is imperative to document their knowledge as an essential component of sonic heritage preservation.

As this study demonstrates, each medieval bell produces a unique sound, notably distinct from those of other bells. Although Norway has an extensive collection of 264 active medieval bells, only two medieval bell foundries have been archeologically identified: one at Sola Church near Stavanger (dating to the late 14th or early 15th century) and another in Trondheim (from the first half of the 15th century) [54]. Further research into medieval bells in Norway could provide insights into their origins, identifying where they were cast and whether specific bells originated from the same foundry.

Medieval bell sounds play a role in community identity. As prominent sound markers, bells were even incorporated into the legal texts of medieval Norwegian towns [55]. Traditionally, medieval churches were positioned strategically and often had a takrytter—a bell turret on the church roof, and a støpul—a freestanding campanile separate from the church. The presence of both structures suggests a significant medieval interest in these percussion instruments, indicating that many churches housed multiple bells. The placement of campanile varied from church to church, likely chosen to maximize the reach of bell sounds across the surrounding landscape. The auditory range of these bells in Valdres was possibly greater in medieval times than it is today, as the region’s economy was predominantly agricultural, resulting in significantly less forest cover than in the present day, which acts as an obstacle to sound propagation.

The sound of bells is considered integral to acoustic heritage and historical soundscapes worldwide [6] (pp. 64–66). It connects people to their surroundings and reinforces a sense of place and belonging, which is essential in shaping urban identity [21]. A recent experience with medieval bells on the Swedish island of Gotland highlighted another fascinating aspect of bell sounds. Gotland is home to 98 medieval churches, constructed between the 12th and 15th centuries, many of which still house active medieval bells. On 8 June 2013, the bells of these churches participated in A Very Large Concert, a composition by Karin Rehnqvist, Claes Holmgren, and Owe Ronström [28]. The sound of over 200 bells was transmitted to a server in Visby and broadcast live on Swedish Radio P2 and the Internet. The project aimed to explore the auditory experience of church bells on a grand scale and demonstrate how even a tiny place like Gotland could possess a powerful voice, essentially unchanged since medieval times. Some listeners claimed to recognize the distinct sound of their local bells. This should not be surprising when we consider that listeners are highly sensitive to subtle differences in bell sounds, being able to detect minor changes ranging from ten to fifteen cents [51]. Additionally, people on Gotland described bell sounds as familiar voices evoking feelings of safety and home (email correspondence with Eva Sjöstrand). As Alain Corbin observed, “A single bell was incapable of stirring the senses as deeply as the interlocking and harmonious peals of a powerful ring” [29] (p. 35). This idea underscores the importance of bell acoustics in historical soundscapes. However, to the best of our knowledge, no formal psychoacoustic study has examined the emotional response to bell sounds in detail or provided scientific validation for such claims.

Future research should focus on documenting traditional bell-ringing techniques, investigating the sound propagation in medieval bells, and exploring the emotional and psychoacoustic responses they evoke. Discussions about preserving active medieval bells must extend beyond the bells themselves to include the local community and people who ring them. Bell ringers are not only skilled practitioners but also masters of traditional arts and bearers of intangible sonic heritage. Without their expertise, a vital link to the past and the unique soundscapes of medieval churches may be lost. By preserving both the bells and the traditions surrounding them, we can ensure that this intangible cultural heritage continues to resonate for generations.

5. Conclusions

Medieval Christian bells as cultural heritage should be addressed in relation to three aspects: (1) as historical artifacts that often carry inscriptions about their commission, bell foundry, and consecration; (2) as an exhibit of the medieval development of metalwork technology; and finally (3) as sonic heritage carriers that produce a locally recognizable voice—“a unique object that serves as a natural symbol of a community’s identity” [29] (p. 73). Our study focused on the latter, examining the sonic heritage of medieval bells from the Valdres region of Norway. It investigated ten medieval bells from five churches, representing about 5% of Norway’s still-active medieval bells.

Our study demonstrated that each medieval bell from Valdres that was examined has a unique tonal structure, thus providing a voice recognizable to the local community. We argued that their distinctive voices play a significant role in community identity, spanning centuries and connecting living people with the soundscapes of their ancestors. These voices come to life through the skills of bell ringers, whose expertise, along with the instruments themselves, is crucial for preserving the sonic heritage of medieval church bells and making their unique sounds heard across the landscape.

Finally, the importance of this study on Valdres medieval bells is threefold: it identifies patterns in the bells’ tonal structures to enhance our understanding of medieval bell tuning practices and expand knowledge of bell tuning across medieval Christian Europe; it confirms that medieval bell sounds are recognizable to local communities because of their unique tonal characteristics; and it highlights the complexity of the sonic heritage of medieval bells, which encompasses not only the instruments but also the bell ringers who play them.