Aliyense amadziwa kuti maginito amafunikira pazida zamagetsi monga okamba, okamba, ndi zomvera, ndiye ndi maudindo ati omwe maginito amasewera pazida zamagetsi? Kodi maginito amakhudza bwanji kutulutsa kwamawu? Ndi maginito ati omwe ayenera kugwiritsidwa ntchito polankhula zamitundu yosiyanasiyana?
Bwerani mudzawone zokamba ndi maginito olankhula nanu lero.
Chigawo chachikulu chomwe chimapangitsa kuti mawu azimveka mu chipangizo chomvera ndi choyankhulira, chomwe chimadziwika kuti choyankhulira. Kaya ndi stereo kapena mahedifoni, gawo lofunikirali ndilofunika kwambiri. Wokamba nkhani ndi mtundu wa chipangizo chosinthira chomwe chimasintha ma siginecha amagetsi kukhala ma acoustic sign. Kuchita kwa wokamba nkhani kumakhudza kwambiri khalidwe la mawu. Ngati mukufuna kumvetsetsa maginito olankhula, muyenera kuyamba ndi mawu omveka a wokamba nkhani.
Wokamba nkhani nthawi zambiri amakhala ndi zigawo zingapo zofunika monga T iron, maginito, coil mawu ndi diaphragm. Tonse tikudziwa kuti mphamvu ya maginito idzapangidwa mu waya woyendetsa, ndipo mphamvu yapano imakhudza mphamvu ya maginito (kuwongolera kwa maginito kumatsatira lamulo lamanja). Mphamvu ya maginito yofananira imapangidwa. Mphamvu ya maginito imeneyi imayenderana ndi mphamvu ya maginito yopangidwa ndi maginito pa wokamba nkhani. Mphamvu imeneyi imapangitsa kuti phokoso la mawu ligwedezeke ndi mphamvu ya maginito a wokamba nkhaniyo. The diaphragm ya wokamba nkhani ndi koyilo ya mawu zimalumikizidwa palimodzi. Liwu likamazungulira ndi khwalala la wokamba nkhani zikugwedezeka pamodzi kuti mpweya wozungulira ugwedezeke, wokamba nkhaniyo amatulutsa mawu.
Pankhani ya voliyumu yofanana ya maginito ndi koyilo ya liwu lomwelo, magwiridwe antchito a maginito amakhudza mwachindunji kumveka kwa wokamba mawu:
-Kuchuluka kwa maginito (magnetic induction) B a maginito, kumapangitsanso mphamvu yogwira ntchito pa nembanemba yamawu.
-Kuchulukira kwa maginito (magnetic induction) B, mphamvu yayikulu, komanso kuchuluka kwa mphamvu ya SPL (sensitivity).
Kukhudzika kwa mahedifoni kumatanthawuza kuchuluka kwamphamvu kwa mawu komwe cholumikizira m'makutu chimatha kutulutsa polozera ku sine wave ya 1mw ndi 1khz. Chigawo cha mphamvu ya mawu ndi dB (decibel), kuwonjezereka kwa phokoso, mphamvu ya phokoso, kotero kukweza kwa mphamvu, kutsika kwa impedance, kumakhala kosavuta kuti mahedifoni azitulutsa mawu.
-Kuchulukira kwamphamvu kwa maginito (kuchuluka kwa maginito) B, kutsika kwa Q mtengo wamtundu wonse wa wokamba nkhani.
Q mtengo (qualityfactor) amatanthauza gulu la magawo a wokamba nkhani damping coefficient, kumene Qms ndi damping wa makina dongosolo, amene amasonyeza mayamwidwe ndi kugwiritsa ntchito mphamvu kayendedwe ka wokamba zigawo zikuluzikulu. Qes ndikuchepetsa mphamvu yamagetsi, yomwe imawonetsedwa makamaka ndikugwiritsa ntchito mphamvu kwa mawu a coil DC kukana; Qts ndiye kutsitsa kwathunthu, ndipo ubale pakati pa awiriwa ndi Qts = Qms * Qes / (Qms + Qes).
-Kuchulukira kwa maginito (magnetic induction) B, kumakhalako kwakanthawi.
Zosakhalitsa zitha kumveka ngati "kuyankha mwachangu" pazizindikiro, Qms ndiyokwera kwambiri. Zomvera m'makutu zokhala ndi kuyankha bwino kwakanthawi ziyenera kuyankha chizindikirocho chikangobwera, ndipo chizindikirocho chimayima ikangoyima. Mwachitsanzo, kusintha kuchokera ku lead kupita ku kuphatikiza kumawonekera kwambiri mu ng'oma ndi ma symphonies azithunzi zazikulu.
Pali mitundu itatu ya maginito olankhula pamsika: aluminium nickel cobalt, ferrite ndi neodymium iron boron, Maginito omwe amagwiritsidwa ntchito mu electroacoustics makamaka maginito a neodymium ndi ma ferrite. Amakhala ndi makulidwe osiyanasiyana a mphete kapena mawonekedwe a disc. NdFeB nthawi zambiri imagwiritsidwa ntchito pazinthu zapamwamba. Phokoso lopangidwa ndi maginito a neodymium limakhala ndi mawu abwino kwambiri, kumveka bwino kwamawu, kumveka bwino kwamawu, komanso kuyimitsa mawu molondola. Podalira ntchito yabwino ya Honsen Magnetics, boron yaing'ono ndi yopepuka ya neodymium inayamba kusintha pang'onopang'ono ma ferrite akuluakulu ndi olemera.
Alnico anali maginito oyambirira omwe amagwiritsidwa ntchito poyankhula, monga wokamba nkhani m'zaka za m'ma 1950 ndi 1960 (otchedwa tweeters). Nthawi zambiri amapangidwa mkati mwa maginito speaker (mtundu wakunja wa maginito umapezekanso). Choyipa ndichakuti mphamvuyo ndi yaying'ono, ma frequency osiyanasiyana ndi opapatiza, olimba komanso osasunthika, ndipo kukonza kumakhala kovuta kwambiri. Kuphatikiza apo, cobalt ndi chinthu chosowa, ndipo mtengo wa aluminium nickel cobalt ndiokwera kwambiri. Kutengera momwe mtengo umagwirira ntchito, kugwiritsa ntchito aluminium faifi tambala cobalt kwa maginito olankhula ndikochepa.
Ferrites nthawi zambiri amapangidwa kukhala olankhula maginito akunja. Mphamvu ya maginito ya ferrite ndiyotsika kwambiri, ndipo voliyumu inayake imafunikira kuti ikwaniritse mphamvu ya wokamba nkhani. Chifukwa chake, nthawi zambiri amagwiritsidwa ntchito polankhula mawu okulirapo. Ubwino wa ferrite ndikuti ndi wotsika mtengo komanso wotsika mtengo; kuipa kwake ndikuti voliyumu ndi yayikulu, mphamvu ndi yaying'ono, ndipo ma frequency osiyanasiyana ndi opapatiza.
Maginito a NdFeB ndi apamwamba kwambiri kuposa AlNiCo ndi ferrite ndipo pakali pano ndi maginito omwe amagwiritsidwa ntchito kwambiri pa oyankhula, makamaka oyankhula apamwamba. Ubwino wake ndikuti pansi pa maginito omwewo, voliyumu yake ndi yaying'ono, mphamvu ndi yayikulu, ndipo ma frequency osiyanasiyana ndi ambiri. Pakadali pano, mahedifoni a HiFi amagwiritsa ntchito maginito otere. Choyipa chake ndi chakuti chifukwa cha zinthu zomwe sizipezeka padziko lapansi, mtengo wake ndi wapamwamba kwambiri.
Choyamba, m'pofunika kufotokozera kutentha komwe kuli kozungulira kumene wokamba nkhani akugwira ntchito, ndikudziwitsani maginito omwe ayenera kusankhidwa malinga ndi kutentha. Maginito osiyanasiyana ali ndi mawonekedwe osiyanasiyana okana kutentha, ndipo kutentha kwakukulu komwe angathandizire kumakhala kosiyana. Pamene kutentha kwa malo ogwirira ntchito kwa maginito kumapitirira kutentha kwakukulu kwa ntchito, zochitika monga maginito attenuation ndi demagnetization zikhoza kuchitika, zomwe zingakhudze mwachindunji phokoso la wokamba nkhani.
