9 ELECTRONIC REINFORCEMENT OF SOUND.ppt

8/15/2019 9 ELECTRONIC REINFORCEMENT OF SOUND.ppt

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ELECTRONIC REINFORCEMENT OF SOUND

REFERENCE:

SCIENCE OF SOUND, 3rd ed., CHAPTER 24

LONG, ARCHITECTURAL ACOUSTICS, CHAPTER 18


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SOUND SOURCES IN A ROOM


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SOUND FIELDS


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POWER

CONSIDERATIONS


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MAXIMUM SOUND LEELS FOR ARIOUS USES

T!PE OF USE MAXIMUM LEEL "d#A$

CLASSROOM 8%

LECTURE HALL 83

S!NAGOGUE 8&

HOME THEATER '%LEGITIMATE THEATER '%

TRADITIONAL CHURCH '%

MOIE THEATER 1%%

FUNDAMENTALIST CHURCH 1%%

SPORTS ARENA 1%&

ROC( CONCERT 11%

S)*r+e: L)-, C/0er 18


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LOUDSPEA(ERS

D!NAMIC

LOUDSPEA(ER

MULTIPLESPEA(ERS IN A

CA#INET

HORN

LOUDSPEA(ER

HORN

CLUSTERS

http://images.google.com/imgres?imgurl=http://www.loudspeakers.net/main/images/articles/features/010305/McCarthey-CCluster02.jpg&imgrefurl=http://www.loudspeakers.net/main/index.php%3Foption%3Dnews%26task%3Dviewarticle%26sid%3D109&usg=__MRCwxB87O_Q1rVGVjZE1l4j7FW4=&h=169&w=225&sz=11&hl=en&start=15&tbnid=Nw2wXq9k7hnHLM:&tbnh=81&tbnw=108&prev=/images%3Fq%3DAUDITORIUM%2BLOUDSPEAKER%2BCLUSTER%26gbv%3D2%26hl%3Den%26sa%3DGhttp://images.google.com/imgres?imgurl=http://www.noteworthyaudio.co.uk/auditorium%2520maple.jpg&imgrefurl=http://www.noteworthyaudio.co.uk/loudspeakers2.html&usg=__WZaCWzjHjhBlHa96iA-B1n75l0c=&h=567&w=309&sz=29&hl=en&start=28&tbnid=d7mW_fYTdHpiLM:&tbnh=134&tbnw=73&prev=/images%3Fq%3DAUDITORIUM%2BLOUDSPEAKERS%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DNhttp://images.google.com/imgres?imgurl=http://www.thetwistergroup.com/store/image.php%3Fimagefile%3DJ%253C%253ESP158A.JPG&imgrefurl=http://www.thetwistergroup.com/product/bogen-sp158a-horn-loudspeakers/SP158A%2520J00789.html&usg=__adJEapaXgc_nnIFw9kZ7lxnIyVc=&h=240&w=186&sz=7&hl=en&start=135&tbnid=sE5GykCwgGI3VM:&tbnh=110&tbnw=85&prev=/images%3Fq%3DHORN%2BLOUDSPEAKERS%26start%3D120%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DNhttp://images.google.com/imgres?imgurl=http://www.soundocity.com/Oregondv/Skaaning_Loudspeakers.jpeg&imgrefurl=http://www.soundocity.com/Oregondv/Skaaning_Loudspeakers.htm&usg=__OAZPvsABaN04vZAGVMGFpaGXIrs=&h=211&w=278&sz=19&hl=en&start=23&tbnid=IjpOSIH5HkrywM:&tbnh=87&tbnw=114&prev=/images%3Fq%3DLOUDSPEAKERS%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN


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#ANDWIDTHS OF ARIOUS SPEA(ERS

T!PE OF LOUDSPEA(ER #ANDWIDTH "H$

1 COMPRESSION DRIER 12%%156

2 COMPRESSION DRIER 8&%1%6

1 DOME TWEETER 2%%%2%63 CONE DRIER 7%%1%6

& CONE DRIER 3&%56

8 CONE DRIER 2&%&6

1% CONE DRIER 2%%46

12 CONE DRIER 1&%26

1& CONE DRIER 8%12&%18 CONE DRIER 7%1%%%

S)*r+e: L)-, C/0er 18


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LOUDSPEA(ER S!STEMS

SINGLE CLUSTERMAINTAINS PROPER RELATIONSHIP #ETWEENTHE SOUND S!STEM AND THE APPARENT SOURCE

MULTIPLE CLUSTERSPROIDES GOOD COERAGE #UT SPREADS

THE APPARENT SOURCE

COLUMN MOUNTEDSUSCEPTI#LE TO INTERFERENCE EFFECTS

DISTRI#UTEDSHOULD INCLUDE TIME DELA! TO MAINATAIN

PROPER RELATIONSHIP WITH DIRECT SOUND

PEW#AC( S!STEMSPROIDES GOOD COERAGE IN CHURCHES


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TIME DELA!

SOUND THAT ARRIES UP TO &% 9 AFTER THE DIRECT SOUND WILL

REINFOCE THE DIRECT SOUND AND !ET PRESERE THE APPARENT

DIRECTION OF THE SOUND SOURCE. TIME DELA! IS ESPECIALL!

IMPORTANT IN THE CASE OF SUPPLEMENTAR! SPEA(ERS

POSITIONED IN PRO#LEM AREAS, SUCH AS UNDERNEATH A

#ALCON! OR FOR SPEA(ERS MOUNTED ON SIDE WALLS.


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HORN LOUDSPEA(ERS


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LOUDSPEA(ER PLACEMENT


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LOUDSPEA(ER

DIRECTIIT!

UNSATISFACTOR!

ARRANGEMENT OF

LOUDSPEA(ERS

RADIATION PATTERN

AND DIRECTIIT!

FACTOR ; FOR A

T!PICAL 8INCH CONE

LOUDSPEA(ER


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ACOUSTIC FEED#AC(


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E;UALI


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ENHANCEMENT OF REER#ERATION

AD=USTMENT OF REER#ERATION TIME IS DESIRA#LE IN MULTIPURPOSE

HALLS. MAXIMUM CLARIT! OF SPEECH DEMANDS A SHORTREER#ERATION TIME, #UT A PIPE ORGAN SOUNDS #EST IN A

REER#ERANT ROOM. ONE SOLUTION IS THE USE OF ELECTRONICALL!

ENHANCED REER#ERATION OR >ASSISTED RESONANCE

ONE METHOD OF ENHANCEMENT PLACES A LOUDSPEA(ER AND

MICROPHONE IN A REER#ERATION CHAM#ERANOTHER USES A NUM#ER OF TRANSDUCERS MOUNTED ON A THIN PLATE

OR FOIL "(UHL PLATE$

DIGITAL REER#ERATORS USE DIGITAL SIGNAL PROCESSING "DSP$ TO

SIMULATE REER#ERATION


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ASSISTED RESONANCE S!STEM

REER#ERATION TIME IN THE RO!AL FESTIAL HALL "LONDON$ WITH

AND WITHOUT ASSISTED RESONANCE "P/r6? /d M)-/, 2'7%$.


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REINFORCEMENT FOR THE HEARING IMPAIRED

SPEECH INTELLIGI#ILIT! CAN #E INCREASED #! PROIDING A WA! TO

ENHANCE THE SOUND AT THE LISTENER@S EAR. THIS CAN #E DONE #! ONEOF FOUR T!PES OF WIRELESS TRANSMISSIONRECEIER S!STEMS:

MAGNETIC INDUCTIONEMPLO!S A LARGE LOOP OF WIRE TO SET UP A

MAGNETIC FIELD THAT CAN #E PIC(ED UP #! HEARING AIDS

FM #ROADCASTING"FCC HAS RESERED A #AND OF HIGH FRE;UENC!

AM #ROADCASTINGOPERATES IN THE #ROADCAST #AND OR #ELOW

INFRARED LIGHTDON@T OPERATE WELL IN #RIGHTL!LIGHTED ROOMS


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MICROPHONE PLACEMENT

MICROPHONES ARE GENERALL! PLACED IN THE DIRECT FIELD OF THE

SPEA(ER OR PERFORMER SO THE MICROPHONE OUTPUT IS REDUCED

#! 5d# FOR EACH DOU#LING OF THE DISTANCE. THIS REDUCES THE

GAIN #EFORE FEED#AC( #! 5d# #UT IT ALSO MEANS THE PERFORMER

CAN MOE A LITTLE WITHOUT PRODUCING A LARGE CHANGE IN LEEL

WHEN A MICROPHONE IS A SMALL DISTANCE A#OE THE FLOOR,

CANCELLATION OF CERTAIN FRE;UENCIES "COM# FILTERING@$ CAN

OCCUR. FOR EXAMPLE, IF THE MICROPHONE WERE 3 9 FROM THE

SOURCE AND #OTH WERE 1.& 9 A#OE THE FLOOR, THE PATH

DIFFERENCE OF THE DIRECT AND ONCEREFLECTED SOUND WOULD #E

1.23 9 AND THE CANCELED FRE;UENC! WOULD #E A#OUT 14% H.


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MULTIPLE OPEN MICROPHONES

WHEN THERE ARE SEERAL MICROPHONES IN USE AT THE SAME TIME,

THE SIGNAL FROM THE LOUDSPEA(ER CAN #E PIC(ED UP #! EACH OF

THEM AND COM#INED AT THE MIXER.

IT IS GOOD PRACTICE IN SPEECH S!STEMS TO USE AN AUTOMATICMICROPHONE MIXER SO THAT THE S!STEM GAIN IS THEORETICALL!

THE SAME AS IT WOULD #E IF ONL! ONE MICROPHONE WERE ON A A

GIEN TIME.


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GRANOFF MUSIC CENTER

TUFTS UNIVERSITY


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OUTDOOR SOUND S!STEMS

SOUND POWER TA(ES ONCONSIDERA#LE IMPORTANCE

SINCE THERE IS NO

REER#ERANT FIELD FOR

REINFORCEMENT.

MULTIPLE LOUDSPEA(ERSAND LARGE AMPLIFIERS ARE

GENERALL! USED.

LOUDSPEA(ERS SHOULD

HAE AS HIGH EFFICIENC! AS

POSSI#LE.


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SPEA(ER CLUSTER AT PRIT


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PRIT


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JAY PRITZKER MUSIC PAVILION

CHICAGO


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PRITZKER PAVILION

IEW OF AUDIENCE FROM THE STAGE


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9 ELECTRONIC REINFORCEMENT OF SOUND.ppt