Wonke umntu uyazi ukuba iimagnethi ziyafuneka kwizixhobo zombane ezifana nezithethi, izithethi, kunye nee-headsets, zeziphi ke iindima ezidlalwa ngumazibuthe kwizixhobo zombane? Ingaba ukusebenza kwemagnethi kunawuphi umphumo kumgangatho wokuphuma kwesandi? Ngowuphi umazibuthe omele usetyenziswe kwizithethi ezineempawu ezahlukeneyo?
Yiza ujonge izithethi kunye neemagnethi zesithethi kunye nawe namhlanje.
Elona candelo linoxanduva lokwenza isandi kwisixhobo somsindo sisithethi, esaziwa ngokuba sisithethi. Nokuba sisitiriyo okanye i-headphones, eli candelo libalulekileyo liyimfuneko. Isithethi luhlobo lwesixhobo sokuguqulela esiguqula imiqondiso yombane ibe yimiqondiso ye-acoustic. Ukusebenza kwesithethi kunempembelelo enkulu kumgangatho wesandi. Ukuba ufuna ukuqonda umazibuthe wesithethi, kufuneka uqale ngomgaqo ovakalayo wesithethi.
Isithethi ngokuqhelekileyo siqulunqwa ngamacandelo abalulekileyo anjenge-T iron, umazibuthe, ikhoyili yelizwi kunye nediaphragm. Sonke siyazi ukuba intsimi yamagnetic iya kuveliswa kwintambo yokuqhuba, kwaye amandla akhoyo achaphazela amandla ombane wamagnetic (ulwalathiso lwamagnetic lulandela umgaqo wesandla sokunene). Umhlaba ohambelana nemagnethi uyaveliswa. Le magnethi isebenzisana nemagnethi eveliswa yimagnethi kwisithethi. La mandla abangela ukuba icoil yelizwi ingcangcazele ngamandla esandi sangoku kwimagnethi yesithethi. I-diaphragm yesithethi kunye nekhoyili yezwi zidibene kunye. Xa i-coil yelizwi kunye ne-diaphragm yesithethi zingcangcazela kunye ukutyhala umoya ojikelezayo ukuze ungcangcazele, isithethi sivelisa isandi.
Kwimeko yomthamo wemagnethi efanayo kunye nekhoyili yelizwi elifanayo, ukusebenza kwemagnethi kunempembelelo ngqo kumgangatho wesandi sesithethi:
-Okukhona uxinaniso olukhulu lwemagnethi (imagnetic induction) B yemagnethi, kokukhona ithrast esebenza kwinwebu yesandi yomelele.
-Inkulu i-magnetic flux density (i-magnetic induction) B, amandla amakhulu, kwaye iphezulu inqanaba loxinzelelo lwesandi se-SPL (uvakalelo).
Uvakalelo lwe-headphone lubhekiselele kwinqanaba loxinzelelo lwesandi apho i-earphone inokuphuma xa ikhomba kwi-sine wave ye-1mw kunye ne-1khz. Iyunithi yoxinzelelo lwesandi yi-dB (i-decibel), isandi esikhulu soxinzelelo lwesandi, isandi esikhulu, ngoko ke uvakalelo oluphezulu, ukuncipha kwe-impedance, kulula ukuba ii-headphones zivelise isandi.
-Oyena mkhulu uxinaniso lwemagnethi (ubunzulu bemagnetic induction) B, ixabiso elisezantsi ngokwentelekiso le-Q yomgangatho uwonke womgangatho wesithethi.
Ixabiso le-Q (i-qualityfactor) libhekisela kwiqela leeparamitha ze-coefficient ye-damping yesithethi, apho i-Qms i-damping ye-mechanical system, ebonisa ukufunxa kunye nokusetyenziswa kwamandla ekuhambeni kwamacandelo esithethi. I-Qes yi-damping yenkqubo yamandla, ebonakaliswa ikakhulu kusetyenziso lwamandla kwi-coil yelizwi ukuxhathisa i-DC; I-Qts yi-damping iyonke, kwaye ubudlelwane phakathi kwezi zimbini zingasentla ziiQts = Qms * Qes / (Qms + Qes).
-Okukhona ubukhulu be-magnetic flux density (imagnetic induction) B, ingcono idlula.
I-Transient inokuqondwa "njengempendulo ekhawulezayo" kumqondiso, i-Qms iphezulu. Ii-earphone ezineempendulo ezilungileyo zexeshana kufuneka ziphendule ngokukhawuleza xa umqondiso ufika, kwaye umqondiso uya kuyeka ngokukhawuleza ukuba uyeke. Umzekelo, inguqu ukusuka kwilothe ukuya kwi-ensemble ibonakala kakhulu kumagubu kunye neesymphonies zemiboniso emikhulu.
Kukho iintlobo ezintathu zeemagnethi zesithethi kwimarike: i-aluminiyam nickel cobalt, i-ferrite kunye ne-neodymium iron boron, Iimagnethi ezisetyenziswa kwi-electroacoustics ikakhulu ziimagnethi ze-neodymium kunye neeferrites. Zikhona ngokobukhulu obahlukeneyo bezangqa okanye iimilo zediskhi. I-NdFeB ihlala isetyenziswa kwiimveliso eziphezulu. Isandi esiveliswe ziimagnethi ze-neodymium sinomgangatho obalaseleyo wesandi, ukuqina kwesandi esilungileyo, ukusebenza kakuhle kwesandi, kunye nokubeka indawo yesandi ngokuchanekileyo. Ukuxhomekeka ekusebenzeni okugqwesileyo kwe-Honsen Magnetics, i-boron encinci kunye nekhaphukhaphu yentsimbi ye-neodymium yaqala ukutshintsha ngokuthe ngcembe iiferi ezinkulu nezinzima.
I-Alnico yayiyeyona magnethi yakuqala isetyenziswa kwizithethi, ezifana nesithethi ngeminyaka yoo-1950 kunye noo-1960 (eyaziwa ngokuba zii-tweeters). Ngokuqhelekileyo yenziwe kwisithethi sangaphakathi samagnetic (uhlobo lwangaphandle lwemagnethi luyafumaneka). Ukungalungi kukuba amandla amancinci, uluhlu lwamafrikhwensi luncinci, lunzima kwaye lune-brittle, kwaye ukusetyenzwa akunzima kakhulu. Ukongeza, i-cobalt sisixhobo esinqabileyo, kwaye ixabiso le-aluminium nickel cobalt liphezulu kakhulu. Ngokwembono yokusebenza kweendleko, ukusetyenziswa kwe-aluminium nickel cobalt kwimagnethi yesithethi kuncinci.
Iiferrites zenziwa ngokubanzi ukuba zizithethi zangaphandle ezinozibuthe. Ukusebenza kwemagnethi ye-ferrite kuphantsi, kwaye umthamo othile uyafuneka ukuhlangabezana namandla okuqhuba esithethi. Ke ngoko, isetyenziswa ngokubanzi kwizithethi zeaudio ezinomthamo omkhulu. Inzuzo ye-ferrite kukuba ingabizi kwaye iyabiza; ukusilela kukuba umthamo mkhulu, amandla amancinci, kunye noluhlu lwamaza okuphindaphinda lumxinwa.
Iipropathi zemagneti ze-NdFeB zingaphezulu lee kune-AlNiCo kunye ne-ferrite kwaye okwangoku zezona magnethi zisetyenziswa kwizithethi, ngakumbi izithethi ezikwisiphelo esiphezulu. Inzuzo kukuba phantsi kwe-flux yamagnetic efanayo, umthamo wayo uncinci, amandla makhulu, kwaye uluhlu lwamafrikhwensi lubanzi. Okwangoku, ii-headphone ze-HiFi zisebenzisa imagnethi ezinjalo. Ukungalungi kukuba ngenxa yezinto ezinqabileyo zomhlaba, ixabiso lezinto eziphathekayo liphezulu.
Okokuqala, kuyimfuneko ukucacisa ubushushu be-ambient apho isithethi sisebenza khona, kwaye unqume ukuba yeyiphi imagnethi ekufuneka ikhethwe ngokweqondo lobushushu. Iimagnethi ezahlukeneyo zineempawu zokuxhathisa ubushushu, kwaye ubushushu obuphezulu bokusebenza abanobuxhasa bukwahlukile. Xa ubushushu bendawo yokusebenza yemagnethi bugqitha ubushushu obuphezulu bokusebenza, izinto ezinjengokuthomalalisa ukusebenza kwemagnethi kunye ne-demagnetization ziyakwenzeka, eziya kuthi zichaphazele ngokuthe ngqo isiphumo sesandi sesithethi.
