CORNER

rl

rl

Lineority - John Wotkinson looks ot what hoppens in the speoker's gop, ond how differenf design slqnls qffect sound quolity.

d h I n. ol drc hlrdùsr pùdùrcrc ro oplinri\.in ! m)\irS..il lrrn!luer. r\ lirrcdù1\ liilnaùnt ch. rh. criLerirnr llncùi r \ i n 1 , ù d s l ) . r k c si r . r c n \ ù \ r \ ù l h c l delrcri rrù rctrNvcd For cxrnrtn. ifr d 1 l 1 r . c r i o o . o n r r o l l.cr h i n d \ h r p . i \ ù s e d .r h c . r . r . . p h o n r er n s r n Sr . r ù , ! c \ \ i i l i n r U o \ . . b u Lr h c ( l r i \ c u t i r i \ i l l h r \ e r o l r en l r . l eù r n c l i n . . r . 'I hrs is b.(.ûs. sr.r.os!\l.nr..llol rh.\irrurl\ounil $ n c . ' \ h i . h r r c t r c r l c { lr r d r i l i r c n l t ) . r n r . L r . r \ c c nl h e ' p ù ! k c r \ n r e ( l u ù 1 ( i\ L ! û r l t x n \ p i r n n t . d r l i l l r ' \ p ù k e ^ . l l ' c s ed i l l è r o f ) i r r r n ' p l i r ù 1 . . \\hrn rh.re ar( ùr.n) und

h c c r u \ ùr ù . n { i o t x l s c l e . l r \ l t } - i l ! ) k n ù s r ! \ r h èe o . l l l r i t r . l ) e l l e . l !un\\ lhc L(encr r'i crùrcnnrlc on \ o u n d L j où r p û t i c u l 0 d i r c c r i o r t o t h c f r r l L l l c x r l u s i o no t . t h c r { ù \ l s 'Ihi\ p h . n o n r r n o nr l j o { s ù l e r û r o d u larrontrùlucr\ lo he herrd $hcn drcr r..'in. d i l l t r c j i rl o e r r n r rl ù t h . ilnrgc Thu\ rhc bcltcf rhe in'asrng tcflirmn!c of! pdirr)f nn,d\pcikcA. rhc liN\cr rh. inrcmr)dul!rn,ndb

n lrr:. foD \hlch i\ lhr sur.l t r u û r h ùof l r l i l l i r ù r 1\ r r d \ I l t h e r ùr \ r r i . s l i g h f u srtr i i l i r e . , l r ) . r l r . r . $ i l l b . i n r e n ù o , l ù l r l i o n$ l r i c h \ i l l p r ) d r ( e n { , D dn { ù ! . s \ h i c h \ c , . i . r i r

Doesdistortionat lf malter?

In nur)d!)nLc ,c|(\lùeri. r tlrcs. l n l c n ù o d u h r c d$ r d \ ) u r r c \ { i l l b . in thc \rnr. tlx.r r\ lhù oriSiDrl ntr,n,i' xDd \,) \ill b. lhrrirlh nl'1.d. Ilùl ir \lef.o. irncrnorlùlrtc{l ! . u r . r i \ i l l D d rb L n j o . l c d i ) $ e l l

l i ' t e r n r o d r l ,n i ) r r i n i d r t r d l r i p l r c q u e ù . i c si \ n b l o h v i o u so n c h o r r l ù L s i e $ ' h c r cr h c r ci r e D u ] \ i n r l d nrùl \ourc.s ir dillèreûl phee\ rn th. ùrgr. !n(l iû llùlc nùr\c.

h lrtr! lie(tù.nc! \N!lc^. rh. \dc\[.id rnd in.o,rÈer un ol p o r r n r sr n d n n ù r n ( c n r e r t \ l h . l ùxr \perke^ {'lt r lii)cû disronlof. 'lhi\ cn. rùsk Nlr lirùârdi\loalon. k r { l i f s k , r h ùp o p ù l l r n U r h t h . ' d À tùriùr docf r nr.rr.f nl lùs lr.qu.ùI I I ! ! n h . r r l I c d n l L r e r r cl t l $ e e t ! rcrl bodhrrnor x rerl lltrp.ûunr r û L ll l r ù \ c r s i o . l i o û r r l ù r d s p . i l ( r - | hr\e ro eonùlùd. ir'\ rh. \p.rliel 'lhc

lir.lrir\ or ùlircr u\c'l in r \ ù r l ù { lr n c l o $ r c p r o h r h l ! h ! s l L )b . b e r r Ùr h r n r h ù u \ e r l i r r p o n t d r l i g i n r . n ' . D r i \ . u . r t \ i n l ù r d c dl n r h i e h q u , l i l r ' I È r k È r . û r \ l h è d è \ r g . L dl 0 eliûinrr( rll polcnri!l !Nr.c\ ol ùor 1 i ù e r r i r yo. l F h i c h r h . r c r r c n ù n j " . O ù 1 \ N h e t ra l l o r r h . \ . h r \ c h . . r {l..lr $ilh $ill lh. n..cs\x.) prrlnr-

ReùcLl)inS ill pr,ttcm\ bul om nra) rrsulr in litilc iùùo!cnrcrr h c c r u \ ùt h c r ù m l l n i n gu o b l e ù p t ! c n r s l h . ù 1 h . r i D F n r v r n ' . n l sb e i g \ o( ol rhe non linca.irie\ in r ùo\ in! coil rrunnhccr ori!inrrc $,lb lhc nrnor s!\tcûr. Onè lo.drrrenlrl fcq0ircmenrrs rhnt drc Inrce gcrerll cd hy 'hc Dot(tr \hould bc nkiepcû de.r oi dr. eoil po\irioû. figure l \ho\v\ rhrr this r.quirc\ drc 1lùr dnlribùri(ù itr dÙ glp k) bc crrcllt \yr' m e r r i e r l\ r r h a r r \ P r r r o l r h c l r i l morc\ our ol onc \nle ol the ficld ]rii ù\r.I1) brlanced b) rhc p!fl of rhr f o i l m o ! i t r . i n o n r h e o r h c rs n l c I)c\rening r \j'Dnrct.tcrl licld r r ù r ù . i \ r o t c s t c . i r l l ] d r r l i c t r l th. ù l rh. prd\ hr\. û!trc conrple\ sh.Ft n i d c , \ r r l i r r l cù r n ' e r o ù ' a k e . ' l l r renrlt i\ lh.t lhe ovctrrhùlnrin! nr(ior ir) ol nùen.rlc qrc!rrs in rodir'i d r i ! e u n i r \ I . s u b { p r i n r n lh c . r u t rh.) rr. J.\ign.d li)r ecoronrl

Spiderwebs l. {ool. . rln .oùe ra\el is lrh ihrr rhepcdi)ûnrnccol rhcsliftrMd nrtround crù !ileer llû.rri11 The n i(tritt ol \p(lc^ in usc l(nht ft h i ! h l t n o n - l i r e nbrc c r u \ .t h t r e \ l o r n,r In,ccii' r ntuI)l)rli{lrnlrL, ddlec tn)n. ln\r..(l ir in!rersei disùolDr rn)nrrel) .\ rhc c(D. nrrc\ sel turn rh.ù.urnlpoi . 'lhis l i ) f l n o l ( l i s r o r t r i nc r n b r rùduc.ddûr)atierllybi nud!inr h0{ : t ) L i l ù rr:. t u r l l t s o . l r û d l n . û r d l r d . \ i s n i i gr h c nr' a r h Ûr h r nj ù \ t . o p ) . n,s $h.r 'hc nrd!(r\ ronnrlh t)rc.

t L E (T R O \ C SW O R L Th) f u i r ! 1 9 9 9 i

I

AUDIO D:SIGN

In tweetc$.lheâùphudc ofnolion is rclarivelysnlll .nd the opcrlting tieque.cyrânscir scll abo\c re$nanccso rhaldrennxionûfthc coDcis màssconlrollcdHer! lhe line!rilyol rhe\pi{leris notsoinrporlrût.but othcrctleclsùc. Theiôrccueatedin thr eoilis caùsed by the lïrv ol curenr inrcrîcringqnh rhenasneriellcld froD rl'c nÉencr.The linesor llux of a quicsecnt\pcakcr motorâre prcci\ely onhogonll to thc dirccrionol llolion and &l as Lhoulh ùeylrc in tcn\nrnasshosn in Fi8.2â). Ite onl) $ry d lorcecù hùcreared is il ùe linesol lbrceùe {lellc.rcdasir 2b) sorharI coDponenrol rcnsion.crs in lhcdire.ti(nrol coilnroli(nr. Asa re$ll. rs thccoil&eclcrltesibF Nô.dslhc 8q' llur is pushcdbàckvûls - LhatNcskD chap alaii ànd rn? ,dra Thc r'(nior ot rhc rlux withinthc ùâgnetrnd lhc nragnetic cirluit canptu InsiderlÈ tnr8net.the only {a} rhll ùe flux can Dove is by lhe \hiliin! ol domain*alls. This requirc\energ).r\ hlftretic ird iundânenhllyDor linerr. Thùsthe llux doesnor ûù)vcsnoothly. bùrin â scricsofjùûrps.

f.tr a) Fluxin gapwilh

ln magicrienpe ând dis[ heâdsLhc r e $ l r ; c r l l c d B À r t h n ù s cnno i s e .l r lotrdsperkcNthe effecris tlîr of pû gr.'n ù ul.rcd noise.sinrilîr but nor idcnric.lro rlrc nrodùlaln'nnoiscof an x!!loBuclûfc recordcr. ()ne say ol sLoppin!ilLrxnùduhti{nl is to use!n clccfi.dlll condu.tivena!netoâedrl.li rhemagner is.ondùdi\e. field n'iis will hale ri) Bcncrrrebuge c d d yc ù û c n r isn . s h o n . i r c u i r .

f.tr b) Distonlon ol rluxneeded lo c@atêdnveblce Flux modùhtionin steelpolcpiecesis rcsisted by lhc srmeeffeclbccausc steel is a conduclû.bul some.icsigners use coppcrplaledI'olc picccsbccrusecopter has much l('wer rcsisliliry rhan

It is insfuclivelo.omprrc nansdùcer constu.ti(,n lcchrologiespracrically. Onecompâri$nwhich is srrikingÈ ro nr.ke a twecterin which thc megnclic circùir can be intc.changed. Usinelbc slme soltwarcwilh a tradilionâlferiLc lists rrâgnerhavingnassproduccdpolesor Use{ulfor clamping shopping Neodlmiùrl!ùgnetsarcclcrrly superi- wiû à Llesilncrneodymiu mqneric orherea thcy.É highlyconducrile. As circunproduccs a emarkablcdiflèrence lbr feûite nr.-!ùcts,well.rhcy ùe insu l.tos.nd scriousloùdsperkcr dcsieners Finally, liDcuritycan potentialll bc only ùse thcnr lo hold $!)pping lisls imprcvcdusingnorionalibcdback.but .nto thc doorol thefridgc, thltrvillhnvc to lvairtar rnorherdne.r

I

h n ù â r yI 9 ( ) UE L E C I R O N I CWSO R L D

l9