Wheelock MX-8 Mixer Specifications download pdf (Page 14)

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Remember,weneed91dBforaneffectivepage.Fromthetable,wecanseethatat64feettheselectionofwattagetaps

givesustheSPLrangeweneed.Atthe7.5wattsettingthehornwillgive93dBwhichiscertainlyadequate.Notethat

at128feetthereisarangeof84dBto90dB(notquitegoodenough)andthatat32feettherangeis90dBto102dB

—probablytoomuch,andspacingthehornsat32feetinsteadof64feetmeanstwicethequantityofhornsandtwice

the money. So, the best choice for front-to-rear spacing is 64 feet.

Thesameprinciplesapplytotheself-ampliedSA-H15horn.Insteadofwattagetaps,however,thereissimplyavolume

control.

Full volume means full power or 15 watts; half volume means half power or 7.5 watts. The SPL and dB

performance is very similar to the 70 volt ST-H15B.

Howmuchareawillthiscover?Multiplytheside-to-sidespacing(40feet)bythefront-to-rearspacing(64feet)—40

feetx64feet=2560sqfeet.Areaofcoverageisusefulbecauseyoucangetaquickestimateoftheactualnumberof

hornsyouneed.Let’ssayyouhavea100,000squarefootareatocover.Youknowfromtakingreadingsthatyouwill

bespacingthehornsat64feetforacoverageof2560sqfeet.Youdivide100,000by2560andget39—thenumber

ofhornsthatyouneedforthejob.

The Nuts and Bolts of an Actual Installation

Thisapplicationofpaging hornsinanoisy(75-85 dB) warehouseandproductionfacility,asshown inthe following

illustration,putsitalltogether:Inthe23,040sqfootproductionareawehave...

  •Dividedby2560sqfeetperhorntoget9horns

• Applied the stagger pattern which used only 8 horns

• Applied the 40 foot side-to-side spacing

• Applied the 64 foot front-to-rear spacing

  •Rememberedtofaceallhornsinthesamedirection(Don’tforgetphasecancellation)

Inwarehouses,wecommonlyencountertallstoragerackscreatingaisles.Theserackseffectivelyblockthe“clearshot”

we need for the horns. The solution is to treat each aisle as a long narrow room. Our example illustrates four aisles.

The horns can be mounted on overhead girders, ducts or on the sides of the storage racks. The horns are arranged

back-to-back, and we have again applied the 64 foot forward coverage.

Ifthewarehousewasquiettomoderate(50-74dB),a“throw”of128feetperhornwouldgeneratesufcientSPLover

ambient noise and...

• Only 4 horns would be needed

  •Eachwithaforwardprojectionof128feet

That means there could be one horn...

• Located at the beginning of each aisle

• Each horn would cover the full length of its aisles

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Wheelock MX-8 Mixer Specifications Page 14