Page 32 - Winter Issue 2018
P. 32

Apparent Gain with Head Inserted I 1 K '1,
Shrine of St Werburgh, Chester Cathedral 3‘ V \ \ _ 
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E 20    '1' l  ‘l Figure 2. David Lubman
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E 10  " i- V‘ -_ l l‘ l  ent gain.{left) produced by
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Z ,' \ -0- Ri hi Ear ‘l ‘
so " 9 I .  2:22? :1:‘::)";?’::::s;’:
.5 l “ll ‘l l lll:,3Tllm‘:’:lBafi ceéfwrfiaqffn ‘ill ('3? :£5ll ll _ . Cathedral ‘in 2003. Figure
courtesy of David Lubman.
evidence. Lubman recounts the study (Personal Communi- hurrian hearing when one’s head is located inside a shrine
cation, 2018): recess. From an interpretative perspective, recess acoustics
“The unusual sound at the shrine of St. Werburgh, at Chester elevate the Relllllllllllg evelll lo lllllefllell” Wllllln llle slllllle
Cathedral (See chestercathedmlfljm) in western England’ recesses, petitioners would hear their own VOICCS. reinforced,
was brought to my attention in 2000 by the English architect allll they wlllllll llllls _be Plllllllplell to ledllce vlllce level Flll
Peter Howell and the architectural historian Iulia Ionides of psyclloacollsllllsf lllls ls llllllwll as llle Lombard llfiecll lllsllle
the Dog Rose Trust, a registered English Charity. Peter and the recesses, petitioners would be less aware of other sounds
Ivisited the Shrine at Chester in July 2003. The shrine had lll lll_e Cllllledlalj The pelltllmeis volces are levilbelaled’
been constructed, moved, rebuilt, damaged, and repaired, lllellllllg lllllllslellous-Solllllllllg levelbelalll lllllll’  ellllfl
with these architectural changes traceable historically. I con- that llllglll,Se.elll lllle lallllllg to anlllhel wllllll lll lllls pllylll
ducted an acoustical experiment to test functional questions Clll and llellglolls wlllelllf Elle lll_llll_l°ly Pelcepl of Pmxlmfty
about the role of sound in the petitioning process, the prayer may lle llllelpleled as s,Plllllllll_l llltllllalcll My lecollsllucllve
requests a Shrine visitor makes to the religious figurem 1_ep_ experiment in re-creating petitioners aural experience is a
resented in the shrine. The shrine is constructed with six re- wall of Fefcreatlng hlstory, demonstrating how sensory ex-
cesses that can receive the head of a kneeling petitioner. In pellellce ls allolllell way olllllowlllg
pre-Reformation times, prayers were spoken while petitioners Lubman’s study of the Shrine of St. Werburgh provides an
knelt at the shrine with their heads in its recesses (Figure 2, empirical complement to historical archaeology, which draws
right). I/Vhat did a petitioner hear? Did the shrine’s acoustical heavily on written texts for experiential accounts. Lubman’s
architecture enhance the petitioner’s experience? My acousti- experimental reconstruction produced a recorded demon-
cal experiment at the shrine sought to find the difference in stration, backed by acoustical metrics, for the architectural
speech quality and spectrum levels heard with one’s head in transformation of speech within the shrine recesses. Via ar-
the shrine versus one’s head outside the shrine. I used head- chaeoacoustics, the effects that were once only possible to ex-
worn binaural microphones to create a high-quality digital perience in person, in situ, can be demonstrated off-site via
recording made with the talker’s (my own) head first inside Lubman’s audio recordings (see links above).'1'he quantitative
(see Multimedia File 1 at acousticstodayorg/lubman-multr data from the archaeoacoustical experiment detail the amount
media) and then outside the shrine recess (see Multimedia of vocal enhancement specific to the experimenter, yet analy-
File 2 at, with the sis of its frequency dependency enables the estimation of the
same vocal efl'ort maintained in both recordings. I then pro- shrine’s acoustical effects for other talkers, thus making the
duced a graph of the apparent gain with the head inside the research extensible to archaeological estimations. Archaeo-
shrine (Figure 2, left), across third-octave bands in the hear- acoustical scenarios that could be modeled using Lubman’s
ing range, comparing the signal from both ears, that tracks data include charting the diiference in acoustical feedback for
how speech levels are greatly enhanced over the range of people with dilferent vocal ranges and characterizing a range
SD ] Acoustics Tuday ] Winter 2018

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