Download - Sound Level of Drumming
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a ayi o sou-lvexou o dum Bug
co puioitBy DouG presley, phD
theNationalInstituteforOccupationalSafetyandHealth(NIOSH)hasrecommendedstandardsfor
sound-levelexposureinvariousworkenvironments.Thesestandardshavebeenderivedfromdecadesofresearchdealing
withworkersexposuretowork-relatedsound-levelenvironments.Thisresearchhasbeenfocusedonthelong-termeffectsofintensesoundonhearingsensitivity,andservestoprotectworkersfromhazardoussound-levelexposurewhileperformingtheirjob-relatedactivities. Twokeyfactorsindeterminingwhetheraworkenvironmentcontainshazardoussoundlevelsaretheaveragesoundlevel(i.e.,decibels)andthedurationofexposure(e.g.,an8-hourworkday).Together,thesefactorsarecalculatedtoproduceaDosePercentage(i.e.,thedailyrecommended
noisedoseforaperson).Aworkenvironmentinwhichthedosepercentageexceeds100%isconsideredtoplacetheworkeratriskfornoise-inducedhearingloss.Table1providesdosepercentagecalculationswithvariousdurationsanddecibel(dB)measurements.
Deciels
(dbA)
8
hour
4
hour
2
hour
1
hour
30
Miue
15
Miue
8
Miue
4
Miue
85 dBA 100% 50% 25% 12.5% 6.25% 3.13% 1.46% 0.78%
88 dBA 200% 100% 50% 25% 12.5% 6.25% 3.13% 1.46%
91 dBA 400% 200% 100% 50% 25% 12.5% 6.25% 3.13%
94 dBA 800% 400% 200% 100% 50% 25% 12.5% 6.25%
97 dBA 1600% 800% 400% 200% 100% 50% 25% 12.5%
100 dBA 3200% 1600% 800% 400% 200% 100% 50% 25%
103 dBA 6400% 3200% 1600% 800% 400% 200% 100% 50%
106 dBA 12800% 6400% 3200% 1600% 800% 400% 200% 100%
Duraion of Exposure
AsreportedinTable1,forevery3dBAincreaseinsoundlevel,thedurationofexposureisreducedbyonehalf.Sound-levelexposureisanaverageofsoundintensity(e.g.,dBA)acrossaperiodoftime.Table2providesasampleofsoundlevels
fromvarioussources,bothmusicalandnon-musical.Table 2 identies sound sources from
varioussources.Sixtypercentofthemusical sound sources identied in Table2generatesoundlevelsof90dBAandabove.Whencomparedtotheallowabledurations identied in Table 1, these soundlevelsshouldnotbeexperiencedformorethanabouttwohours(91dBA),andforaslittleasfourminutesat106dBA.Typicalrehearsalsand/orpracticessessionswiththeseinstrumentsalmostalwaysexceedfourminutesandcanregularlyexceedtwo
hours. Insituationswhereexcessivesound-levelexposureisexperiencedwithoutobviousdamagetothehearingorgan(e.g.,atearingoftheeardrumoraPermanentThresholdShift[PTS]),effectsfromtheexposuremaysubsideduringaperiodofeffective
tab 1
A mb ab 100% daga a 100% d ad amb a fa bw 100% daga ag ga a100%.
quiet.IncaseswherethereisnoPTS,aTemporaryThresholdShift(TTS)maybepresent;inthiscasetheeffectsmaysubsideoveraperiodoftime.Clark(1992)reportedthatattendeesatarockmusicconcertexperienceaTTSthattypicallysubsidesa
fewhourstoafewdaysaftertheexposure.Therefore,recoveryofthehearingorganmaytakeaslongasafewdaysduringnormalconditions,orconditionswithinthesound-levelexposureparametersprovidedabove. Inallcases,however,anyevidenceofdegenerativehearinglossornoise-inducedhearingloss(NIHL)canonlybedeterminedaudiometrically.Thedurationsneededforeffectivequietfollowinganynumberofexcessivesound-levelexposuresisidiosyncraticandonlydetectablethroughaudiometerictesting.Additionalresearch
ontherecoverytimeamongpercussionistsfollowingperformancesand/orrehearsalswouldbeveryhelpful. Anemergingconcernforhealth-relatedissuesattributedtopercussionperformanceisevidencedthroughtheincreaseofpublishedarticlesandstudieson musicians health and, specically,soundexposuresandhearingconservation.Forexample,in2004,Juman,Karmody,andSimeon,onegroupstudiedthehearingacuityandsound-levelexposureofsteeldrumbandmembers.Duringrehearsaldurationsof68hours,thesubjectssound-
levelexposurerangedfrom97.9dBAto110.7dBA.TheNationalInstituteofOccupationalSafetyandHealth(NIOSH)recommendsthatexposuretosoundlevelsof97.9dBAshouldnotexceed30minutesandexposureto110.7dBAshouldnotexceed90seconds(seeTable1).Jumanet.al.2004alsoreportedthatsubjectshearingsensitivity was signicantly less than a peergroupofnon-musicians. Anothergroup(Cunningham,Workman,Curk,Hoffman,andPride,2005)studiedthehearingsensitivityofpercussionists
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Source Sound Level
(dbA)
Guo 140
Ambuae sire 120
car hor 115
Snare Drm 115
Diee truk 100
Piccolo Fle 100
Wind Ensemle 98
Jazz trio 97
Alo Saxophone 96
brass Qine 96
barione Voice 95
Clarine 93
Soprano Voice 91
Insrmenal Ensemle 91
Piano & ta 91
lawmower 90
Horn 90
bassoon 87
Woodwind trio 86
Choral Ensemle 84
Cello 82
ciy traf 80
Piano 80
Violin 79
Srin bass 75
Acosic giar 72
vauum ceaer 70
norma coeraio 60
tab 2
im old df m d.
acrosstwoyearsduringthe2003and2004PercussiveArtsSocietyInternationalConventions.Thisgroupreportedthatpercussionistshearingsensitivitywasworsethanthatofpeersofthesameagewithoutsimilarexposuretopercussion-relatedsounds.Additionally,audiogramsof25%ofsubjectsshowedcharacteristicsofnoise-inducedhearingloss(NIHL). Together,thesetwostudies(Cunningham,Workman,Curk,Hoffman,andPride,andJuman,Karmody,andSimeon)presentdataindicatingthat
percussionistsareexposedtosoundlevelsthatexceedrecommendedstandards,aswellassoundlevelsthatmaydamagehearingsensitivity.Inlightofthesendings, it would be appropriate to
determineifthesound-levelexposurewithinotherpercussionenvironmentsisexcessive.Thisraisesthequestion,ifanenvironmentisfoundtoyieldexcessivesoundlevels,whatcanbedonetoprotectthehearingsensitivityofthosepercussionists? Thecurrentstudyanalyzedthesound-levelexposuresofdrumandbuglecorpspercussionistsduringafull-dayrehearsalof12:15(hr:min).ParticipantsweremembersofaDivisionIdrumandbuglecorps.DatawerecollectedduringtheSpringtrainingperiodinJuneof2004.Theentirerehearsal
daytookplaceoutdoorsonvariousathletic elds. Subjects (N=15)performedonbatterypercussion(n=8)andfrontensemblepercussion(n=7)instruments.Apersonaldosimeterwasattachedtoanathleticvisorthatwaswornbyeachsubjectthroughouttherehearsalday.Thedosimetercollectedandcalculatedsound-leveldatarelativetoNIOSHstandardsfora12-hourworkday(i.e.,anaveragesoundlevelof83dBAfora12-hourduration,NIOSH,1998).Subjectsalsocompletedamusic-experiencequestionnaire. Snaredrumsubjects(n=4)reported
anaverageofthreeyearsexperienceindrumandbuglecorpsactivities;tenordrumsubjects(n=2)1.5years,bassdrumsubjects(n=2)2.5years,vibraphonesubjects(n=3)1.67years,auxiliarypercussionsubjects(n=2)2.5years,andthemarimbasubjectreportedthreeyearsofdrumcorpsexperience.Additionally,60%ofallpercussionsubjectsparticipatedinhighschoolindoor/winterdrumline,47%incollegeindoor/winterdrumline,73%inhighschoolpercussionensemble(non-marching),and67%incollegepercussionensemble(non-marching).Acrossall
subjects,87%reportedparticipationinscholastic-levelmarchingbandandindoordrumlineand/orpercussionensemble(non-marching)inadditiontoparticipatingindrumandbuglecorps.Nosubjectreportedthatheorsheusedhearingprotectionandfoursubjectsreportedknownhearingproblems(e.g.,ringingintheear,worsehearinginoneearthantheother,etc.).
These ndings indicate a substantialamountoftimeofparticipationinpercussion-onlyensembles(scholastic-
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level)inadditiontothedrumandbuglecorpsactivity.Itshouldalsobenotedthatthescholastic-levelpercussiongroupstypicallyusethesameinstrumentationasthatfoundinadrumandbuglecorps
(e.g., free-oating marching snare drum,marchingbassdrum,marchingtenors,etc.).Therefore,itispossiblethatthesoundlevelsfoundinthissampleofdrumandbuglecorpssubjectsaresimilartothosefoundinscholastic-levelpercussiongroups. DatapresentedinTable3identifytheinstrument,averagesoundlevel(Leq),durationofexposure,anddosepercentagesforallsubjects.TheLeqistheoverallaverageofthemeasuredsoundlevels,whichincludesbreaks(lunch,dinner,etc.).ThecolumnlabledDurationofExposureTimeincludesthetotalnumber
ofminutesfortherehearsaldayof12:15(hr:min),includingrelativelyshortandextendedbreaks(i.e.,lunchanddinner).Dosepercentagesexceeding100%indicatehazardoussound-levelexposuresthatmayresultinlong-termdamagetothehearingorgan.Forreferencepurposes,theNIOSHstandardsfora12-hourdayarepresentedinthe rst line of Table 3. AsreportedinTable3,allsubjectsexceededthe12-hourLeqof83.0dBA.Asaresult,allsubjectsexceededadoseof100%,andallbutonesubjectexperiencedgreater
Insrmen Leq (Averae Sond
Level)
Draion of Exposre
time
Dose Percenae
NIOSH Standards 83.0 dBA 720 minutes 100.00%
sare Drum 1 102.3 dBA 735 8822.29%
sare Drum 2 102.6 dBA 735 9455.49%
sare Drum 3 103.1 dBA 634 9154.99%
sare Drum 4 100.2 dBA 735 5319.92%
teor Drum 1 99.4 dBA 735 4422.12%
teor Drum 2 98.9 dBA 735 3939.66%Ba Drum 1 99.8 dBA 735 4850.29%
Ba Drum 2 94.4 dBA 735 1392.88%
Aux. peruio 1 93.8 dBA 735 1212.57%
Aux. peruio 2 93.8 dBA 735 1212.57%
vibraoe 1 94.0 dBA 735 1269.92%
vibraoe 2 96.9 dBA 735 2481.83%
vibraoe 3 92.5 dBA 735 897.97%
Marimba 93.6 dBA 735 1157.82%
timai 93.4 dBA 735 1105.53%
tab 3
thantentimestheallowablesound-levelexposurefora12-hourday.Duetoalowbattery,thedosimeterusedforSnareDrum3turnedoffbeforetheconclusionoftherehearsalday.ExposuretothelowestL eq
(92.5dBA)providedinTable3shouldnothaveexceededadurationof120minutes,andexposuretothegreatestLeq(103.1dBA)shouldnothaveexceededeightminutes(seeTable1).However,inthisstudythese
averageswereexperiencedfor735minutes,which is a signicantly greater amount oftimethanrecommendedbyNIOSH. Kryter,Ward,Miller,andEldredge(1966)determinedadamage-riskcriteriarelativetotheamountofpeaksound-level(i.e.,soundlevelsthatexceed140dBA)occurrencesduringan8-hourworkday.Kryter,etal.determinedthatoveran8-hour
period,theoccurrenceofpeaksound-levelsmaynotexceed100,orexceed4.8%oftheexposuretime.Inthisstudy,snaredrumsubjectsexperiencedpeaksoundlevels31%,45%,38%,and39%oftherehearsaltime.Exceptforonebassdrumsubject(whowaspositionednexttothesnaredrums),nootherpercussionistexceeded13%,withmostfallingbelow10%.Althoughthelesservaluesexceedthedamage-riskcriteria,itwasclearthatthesnaredrumsubjectshadexcessiveexposure. Theexcessiveexposurerelativetothe
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damage-riskcriteriaamongsnaredrumsubjectsmaybeattributedtoacombinationof the Kevlar-brand bers used in the snaredrum heads and the free-oating snaredrumshelldesign.Thesetwofactorsallow
theperformertostriketheinstrumentwithgreaterforce,thusincreasingthesound-pressurelevel.Thesurfacetensiononthesnaredrumheadmayhavecontributedtogreatersound-levelproductionwhencomparedtotheotherpercussioninstruments.
Twenty-ve percent ofthemeasureddaycontainedfull-corpsrehearsals(i.e.,brassandpercussion),anddinnerandlunchbreakscomprised13%oftheday.Therefore,62%ofthe
percussionistsrehearsalday(7hrs.40mins.)involvedpercussion-onlyrehearsalactivities.Althoughthepresenceofbrassinstrumentsduringthefull-corpsrehearsalscontributedtotheLeq,morethan50%ofthesound-levelexposurecanbeattributedtopercussioninstrumentsalone. Additionaldataanalysiswaspursuedtoexaminetheeffectsofhearingprotectiondevices(HPD)onthereductionofsoundlevelsacrossallpercussionsubjects.TwohypotheticalHPDuseswereconstructedforeachsubject:(a)intermittentuseof
HPD(i.e.,76%oftherehearsalday,or559minutes),and(b)extendeduseofHPD(87%oftherehearsalday,or643minutes).Intermittentuseincludessound-levelexposuresduringsmallgroup(e.g.,snaredrumsonly,bassdrumsonly,etc.),andfullcorpsrehearsalactivitiesonly.Extendeduseincludedallrehearsalactivities(i.e.,smallgroup,largegroup,andfullcorps).BothhypotheticalparametersassumedremovalofHPDduringextendedbreaks(i.e.,lunchanddinner). ThereductioneffectswerebasedontheuseofanHPDwithanoise-reductionrating
(NRR)of30(i.e.,areductioneffectof30dBofsoundlevelswhenproperlyinserted).TheseHPDsarecommerciallyavailableasmusiciansearplugsandtypicallycostaround$120.00.Table4providesdataonthepossiblereductioneffectsofHPDswithin
both Intermittent Use and Extended Useparameters. AsreportedinTable4allsubjectsLeqwouldfallwithinNIOSHstandards(i.e.,Leqof83dBAfora12-hourday)withtheextendeduseofanHPDwithaNRR-30.Althoughthelikelihoodthatpercussionists
percussionists hearing sensitivity was worse
than that of eers of the same age without
similar exosure to ercussion-related sounds.
Sjec Leq w/Inermien use of
NRR-30
Leq w/Exended use of
NRR-30
sare Drum 1 91.8 dBA 79.9 dBA
sare Drum 2 92.4 dBA 81.9 dBA
sare Drum 3 93.5 dBA 78.1 dBA
sare Drum 4 89.9 dBA 71.9 dBA
teor Drum 1 89.2 dBA 70.9 dBA
teor Drum 2 88.4 dBA 70.5 dBA
Ba Drum 1 88.1 dBA 77.0 dBA
Ba Drum 2 83.2 dBA 74.1 dBA
Aux. peruio 1 86.2 dBA 68.1 dBA
Aux. peruio 2 86.0 dBA 68.0 dBA
vibraoe 1 87.7 dBA 67.4 dBA
vibraoe 2 90.1 dBA 69.2 dBA
vibraoe 3 84.8 dBA 70.5 dBA
Marimba 85.6 dBA 68.0 dBA
timai 85.7 dBA 71.1 dBA
tab 4
wouldwearanHPDforthisamountoftimemaybequestioned,theprotectionprovided
by the use of an HPD would signicantlyreducetheeffectsofthistypeofexposure.Intermittentusedidnotindicatethatany
ofthesubjectsLeqswouldfallwithinrecommendedguidelines;however,therewasadrasticreductioninLeqsacrossallsubjectswhencomparedtoLeqsprovidedin Table 3. Under the conditions of thisstudytheuseofanHPDwithaNRR-30woulddiminishtheriskoflong-termeffects
resultingfromtheobservedsound-levelexposures. Inconclusion,thisstudyfoundthatpercussionistsexperiencedsoundlevels(Leq)anddosepercentagesthatexceededrecommendedstandardsfora12-hourday.ThesnaredrumsubjectsexperiencedgreaterLeqs(102.3dBA,102.6dBA,103.1dBA,and100.2dBA),whileVibraphone3experiencedtheleastLeq
(92.5dBA).
These12-hourLeqsincludedalunchanddinnerbreak,andseveralshortwaterbreaksthroughouttheday.Addtionally,
allpercussionistsinthisstudyexperienceddosepercentagesgreaterthan100%andallbutone(vibraphone3)experiencedgreaterthan10timestherecommendedlimit.Snaredrumsubjectsexperiencedthegreatest
dosepercentages(i.e.,8822.29%,9455.49%,9154.99%,and5319.92%).Thesepercentagesarealmost100timesgreaterthantherecommendedlimit. BatterypercussionsubjectsexperiencedgreaterLeqsthanthefrontensembleasawhole.Thiscouldbeattributedtothe
designofthemarchingpercussioninstruments.Thismayalsobetheresultof the specic musicalpartsassignedtoeachpercussionist.Thebatterypercussionsectionmay
haveperformedmorenotesthanthefrontensemble. Subjectsalsoreportedparticipationintypicalseasonalpercussion-relatedensembles(i.e.,marchingband,indoor/Winterdrumline,percussionensemble,anddrumcorps)thatspanacalendaryear.Sincethepercussioninstrumentationfoundincorpsissimilartothatfoundinotherscholastic-levelpercussion-relatedensembles,thisindicatesthatthesound-levelexposuresofpercussionistsfoundinthisstudymaybeexperiencedthroughoutacalendaryear,andnotonlyduringthe
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summermonthsofdrumcorps.Thislong-termexposureneedsfurtherresearch;however,itissafetosaythatpercussionistsengagedinpercussionensembleactivitiesthroughoutanentireyearneedtoseriously
considerusinghearingprotection. Theuseofhearingprotectiondevices(HPD)wereshowntoreducesound-levelexposure,andmaypossiblydosototheextentthatsubjectswouldfallwithinNIOSHstandards,therebydiminishingthepotentialforlong-termhearingdamage.ThecommercialavailabilityofsuchHPDscombinedwiththeprotectiontheyaffordpercussionistspresentsfeasibleandsufcient protection during percussion-relatedensembleperformances. Audiometrictestingwasnotadministeredtothesubjectsofthisstudy,
sothepresenceorabsenceofhearinglosswasanecdotal.Futuretestsshouldincludeaudiometrictestingbefore,during,andafterthesetypesofactivitiestodeterminetheimmediateeffectsofthesedegreesofsound-levelexposure.Casestudiesmayincludeapercussionistandthemeasurementofhisorherpercussion-relatedperformanceactivitiesthroughoutacalendaryear,combinedwithperiodicaudiometrictesting.Thecombinationofsound-levelmeasurementsandaudiometrictestingwithinthesamestudywouldprovidesignicant information as to the long-term
andshort-termeffectsofpercussionistssound-levelexposure.
references
Clark,W.W.(1992).Hearing:theeffectsofnoise.Otolaryngology Head and Neck Surgery,106,669.
Cunningham,D.,Workman,D.,Curk,A.,Hoff-man,J.,&Pride,J.(2005).Hearingloss:Newresearchonpercussionists.Percussive Notes,43:6,December2005,4447.
Juman,S.,Karmody,C.S.,&Simeon,D.(2004).Hearinglossinsteelbandmusicians.Otolaryn-gology Head and Neck Surgery,131,461465.
Kryter,K.D.,Ward,W.D.,Miller,J.D.&
Eldredge,D.H.(966).Hazardousexposuretointermittentandsteady-statenoise.Journal ofAcoustical Society of America,39,451464.
NationalInstituteforOccupationalSafetyandHealth(1998).Criteria for a recommended stan-dard: occupational exposure to noise.PublicationNo. HSM 73-11001.Cincinnati,Ohio.
Dr. Douglas L. PresleyisDirectorofBandsandInstrumentalMusicatLimestoneCol-legeinGaffney,SouthCarolina.Contacthimat:[email protected]. PN
PAS THANKS ITS
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