Acoustic crossovers yog cov khoom siv hluav taws xob uas siv ib lub teeb liab tawm tswv yim thiab tsim ob lossis peb qhov tawm uas muaj qhov sib cais siab, nruab nrab thiab tsawg zaus. Ntau qhov sib txawv pub cov neeg hais lus sib txawv lossis "tsav tsheb" hauv lub suab: woofers thiab subwoofers. Yog tsis muaj crossover, random tawg ntawm lub suab tshwm sim. Hauv cov no, lub lim dej siab dhau qis qis tab sis xa cov ntawv sau ntau zaus rau lub tweeter, thaum lub lim dej qis qis blocks siab thiab dhau cov ntawv qis qis rau lub subwoofer.
Component suab system
Crossover "networks" ntawm coaxial ntau lub tsheb hais lus feem ntau yog ua rau cov neeg hais lus thiab muaj cov khoom siv hluav taws xob me xws li coils lossis capacitors. Crossovers rau peb-txoj kev tshuab siv tweeters, midrange tsav tsheb, thiab subwoofers suav nrog, ntxiv rau cov lim dej siab thiab qis,"bandwidths" rov tsim dua zaus ntawm ob lub ntsiab lus siv ob qho tib si siab thiab qis zaus ntawm tib lub network. Rau qhov no, tej zaum yuav muaj tus tsav tsheb nruab nrab ntawm 100 Hz txog 2500 Hz.
Muaj ob lub ntsiab ntawm acoustic crossovers: nquag thiab passive. Passive sawv daws yuav tsis xav tau lub zog los lim cov teeb liab. Cov neeg nquag xav tau lub zog thiab kev sib txuas hauv av, tab sis muab kev yooj yim dua rau koj thiab tswj cov neeg siv suab paj nruag.
Active audio system
Ib lub suab hu ua "active" thaum txhua tus neeg tsav tsheb, tweeter, woofer muaj nws tus kheej amplification channel. Qhov no ua rau kom muaj lub zog muaj zog, muaj zog ntau thiab kev tswj hwm lub suab lus teb thoob plaws tag nrho lub suab spectrum. Ib qho acoustic active crossover txuas ntawm lub receiver thiab amplifier thiab txiav tawm cov zaus tsis xav tau yog li nws tuaj yeem tsom mus rau cov zaus uas tus neeg siv xav hnov.
Lawv feem ntau muaj kev tswj hwm qhov ntim ntawm txhua qhov channel, yog li koj tuaj yeem khaws tag nrho "suab" los ntawm cov tsav tsheb sib txawv hauv qhov sib npaug. Qee qhov crossovers suav nrog lwm cov kev ua suab nrov xws li kev sib npaug kom ntxiv kho qhov system. Qhov tsuas muaj peev xwm downside rau hom crossover no yog tias nws xav tau + 12V, hauv av, thiab plug-in txuas. Qhov no nthuav tawm qhov teeb meem loj dua rau kev teeb tsa thiab teeb tsa dua li lub cuab yeej passive.
Passive acoustic devices
Acoustic passive crossover tsis txuas nrog lub hwj chim. Muaj ob hom passive crossovers: tivthaiv crossovers, uas yog kev cob cog rua ntawm lub amplifier thiab hais lus, thiab built-in sawv daws yuav, uas yog nyob nruab nrab ntawm lub receiver thiab amplifier.
Cov. Cov kev hloov pauv tsis tu ncua ntawm cov khoom hauv lub teeb liab txoj kev tuaj tom qab lub amplifier. Cov no yog cov sib txuas me me ntawm cov capacitors thiab coils uas feem ntau tau teeb tsa ze ntawm lub suab nrov. Cov lus hais los nrog cov crossovers teem rau kev ua haujlwm zoo. Lawv yooj yim rau nruab thiab teeb tsa. Tag nrho cov teeb liab tawm ntawm lub amplifier thiab mus rau passive crossover uas faib nws ua ob thiab xa cov ntawv siab mus rau tweeter thiab nruab nrab thiab qis rau woofer. Feem ntau passive tivthaiv crossovers muaj cov chaw ntxiv uas tso cai rau koj tua lub tweeter yog tias lub suab zoo li nrov dhau rau woofer.
Ntxiv rau qhov kev hla hla dhau uas ua haujlwm ntawm lub suab nrov nrov thiab txuas nrog ntawm lub tshuab hluav taws xob thiab cov lus hais, kuj tseem muaj cov tsheb sib txuas ua ke uas tau teeb tsa rau pem hauv ntej ntawm lub tshuab hluav taws xob. Lawv zoo li lub tog raj kheej me me nrog RCA plugs ntawm txhua qhov kawg thiab tsuas yog ntsaws rau hauv cov khoom siv. Built-in crossovers tsis nkim lub zog zoo li cov zaus siab ua rau lub subwoofer. Kev txhim kho lub hauv paus crossover yog ib txoj hauv kev zoo thiab pheej yig los txhim kho lub suab ntawm qhov chaw, tshwj xeeb tshaj yog nyob rau hauv cov lus hais lus.
Txoj cai siv lub tsheb
Yuav kom nkag siab tias crossover yog dab tsi thiab seb qhov kev xav tau ntawm lub suab tiag tiag xav tau ib lossis ntau qhov kev sib tw, nws yog ib qho tseem ceeb ua ntej kom nkag siab qee cov ntsiab lus yooj yim heev rau kev siv lub tsheb crossover. Lub tswv yim tseem ceeb yog cov suab paj nruag yog tsim los ntawm cov suab nrov uas tswj hwm tag nrho cov gamut ntawm tib neeg hnov, tab sis ib tus neeg qhov chaw zoo dua ntawm kev tsim cov zaus ntau dua li lwm tus.
Tweeters yog tsim los tsim cov zaus ntau zaus, woofers yog tsim los tsim cov zaus qis, thiab lwm yam. Lub hom phiaj tseem ceeb yog cais cov suab paj nruag rau hauv nws cov khoom siv ntau zaus thiab xa mus rau cov neeg hais lus tshwj xeeb kom ua tiav lub suab zoo dua. Los ntawm kev ua kom paub tseeb tias tsuas yog cov zaus raug mus txog koj cov neeg hais lus classic, koj tuaj yeem txo qhov cuam tshuam zoo dua thiab txhim kho lub suab zoo ntawm koj lub tsheb suab system.
Kev txhim kho passive acoustic crossovers yog ib txoj haujlwm yooj yim vim nws muab kev sib txuas sib txuas ntawm lub amplifier thiab hais lus. Piv txwv li, koj tuaj yeem txuas tus passive crossover mus rau qhov tso zis tawm suab, tom qab ntawd txuas lub tweeter tso zis rau lub tweeter thiab lub subwoofer tso tawm rau lub subwoofer.
Kev teeb tsa lub tsheb sib tw ua suab nrov feem ntau yuav yog cov txheej txheem nyuaj dua. Qhov teeb meem tseem ceeb yog qhov kev sib tw ua haujlwm yuav tsum muaj lub zog, yog li koj yuav tsum tau khiav lub zog thiab hauv av xaim rau txhua lub cuab yeej. Yog twb ntsia lawmamplifier, nws yuav yooj yim rau nruab ib tug active crossover. Qhov tseeb, grounding nws nyob rau tib qhov chaw raws li lub amplifier yog grounded yuav pab tiv thaiv kom txhob muaj suab nrov nyob rau hauv lub voj voog.
Crossover Classification
Acoustic crossovers tuaj yeem faib los ntawm tus lej ntawm cov bands uas lub suab spectrum faib. Ob txoj kev faib cov suab spectrum rau hauv ob qhov chaw thiab xa cov ntaub ntawv mus rau ntau hom kev tsav tsheb. Peb-txoj kev faib cov suab spectrum ua peb ntu, thiab lwm yam. Ib qho kev hla kuj tuaj yeem piav qhia los ntawm qhov chaw uas qhov kev txiav nyom pib. Nws feem ntau yog hais txog qhov zaus ntawm qhov pib qhovntsej thiaj tsis mob. Hauv duplex, ob tus neeg tsav tsheb yuav muaj 6 dB ntawm qhov chaw hla.
Cov ntsiab lus feem ntau siv los piav txog txoj kab nqes hla suav nrog 6 dB / octave, 12 dB / octave, 18 dB / octave, lossis 24 dB / octave. Txoj kab nqes ntawm crossover uas cov ntsiab lus hais txog. Rau ib qho kev hloov octave, 6 dB / octave crossover yuav muaj qhov tso zis uas yog 6 dB hauv qab qhov pib; 12 dB / octave yuav muaj 12 dB tso zis. Lwm cov ntsiab lus uas feem ntau siv los piav txog txoj kab nqes hav yog 1st Order, 2nd Order, 3rd Order, thiab 4th Order.
Cov ntsiab lus no yog muab los ntawm cov khoom siv uas xav tau los tsim txoj kab nqes piav qhia. Ib qho kev txiav txim thib 1 siv 1 feem thiab yuav muab kwv yees li 6 dB / octave. Kev txiav txim thib 2 yog siv 2 yam khoom thiab yuav muab rau koj txog 12 dB / octave, thiab lwm yam.
Center speaker components
Yog tias nws nyuaj rau nrhiav tus nqi uas tsis ntau tshaj 10% ntawm lub suab xav tau, kho. Ntawm noQee cov lus qhia rau kev ua haujlwm nrog cov khoom sib txawv:
- Capacitors: muab ob lub capacitors, txuas rau lawv ua ke. Siv lawv li no, ib tus tuaj yeem yooj yim ntxiv ob qhov txiaj ntsig ua ke kom tau txais cov peev txheej sib npaug.
- Resistors: txuas ob lub resistors hauv koob los muab kev sib xyaw ua ke sib npaug rau tag nrho tus nqi. Lub zog ntsuas ntawm ob qho tib si yuav tsum siab kom ua tau raws li qhov yuav tsum tau ua.
- Inductors: Yog tias koj tsis tas yuav siv ntau lub inductors, koj tuaj yeem yuav ib qho loj thiab tom qab ntawd tshem cov coils kom txog rau thaum tus nqi xav tau. Qhov tsis zoo ntawm txoj kev no yog tias koj yuav tsum siv ib hom kev ntsuas inductance.
Define ntau zaus
Kho qhov crossover ntawm tus neeg hais lus yog qhov kev hloov kho kom raug. Txhawm rau txiav txim siab qhov kev tso cai uas siv rau kev teeb tsa, koj yuav tsum paub cov ntaub ntawv rau ob tus neeg hais lus thiab lub subwoofer. Lub pob hais lus yuav khoom ib txwm muaj phau ntawv qhia rau kev teeb tsa koj xav siv.
Txwv tsis pub, cov cai hauv qab no siv tau. Qhov siab tshaj plaws uas lub subwoofer tuaj yeem siv tau yuav tsum tau siv rau kev teeb tsa crossover. Qhov zaus qis tshaj plaws uas tus neeg hais lus tuaj yeem ua tau yuav tsum tau teem rau crossover.
Piv txwv li, rau lub subwoofer zaus ntau ntawm 20-130Hz thiab lub chaw hais lus ntau zaus ntawm 70-20,000Hz, qhov kev tso cai ntauKev teeb tsa crossover rau lub ntsiab lus yuav yog 70-130 Hz. Qhov no txhais tau tias koj tuaj yeem siv qhov teeb tsa ntawm 70, 80, 90, thiab lwm yam, mus txog 130 Hz rau lub ntsiab lus. Yog tias siv saum toj no lossis qis dua qhov loj me, ces cov zaus sab nraud ntawm qhov txwv yuav tsis rov ua dua los ntawm lub subwoofer lossis tus hais lus sib xws.
Main building blocks
Nyob hauv lub tsheb lub kaw lus, cov khoom siv hluav taws xob loj loj tau siv los tiv thaiv lub teeb kom tsis txhob ploj thaum lub suab bass thaj tsam nrov. Lawv ua tiav qhov no los ntawm kev muab lub suab nrov nrawm nrawm ntawm lub zog. Tus neeg hais lus crossover capacitors muaj qhov siab "kuj" feem ntau hu ua reactive rau qis zaus signals.
Muaj peb lub ntsiab lus tshwj xeeb rau cov capacitors:
- Qhov siab tshaj qhov hluav taws xob uas nws tsis raug cuam tshuam los ntawm kev hais lus. Qhov kev puas tsuaj no tshwm sim thaum hluav taws xob hluav taws xob nruab nrab ntawm ob daim phiaj ntawm lub capacitor ua kom txaus rau polarize lub dialectic, yog li tig nws mus rau hauv tus neeg xyuas pib. Thaum qhov no tshwm sim, lub capacitor yuav kub thiab tuaj yeem tawg.
- Cov capacitance ntawm capacitors feem ntau ntsuas hauv microfarads - mF lossis uF lossis (Greek tsab ntawv mu) F. Ib microfarad yog 1/1,000,000 lossis 1 × 10 -6 Farad. Thiab Picofarads kuj tseem siv, uas yog 1/1,000,000 lossis 1 × 10 -6 microfarad (1 × 10 -12Farad).
- Txhob Cia Siab. Qhov no yog ib qho kev hloov pauv ntawm tus nqi. Piv txwv li, 47mF capacitor nrog qhov ntau ntawm -20% / + 80% yuav yogmuaj peev xwm ntawm 37.6 mus rau 84.6 mF. Lub tshuab suab feem ntau txuas lub capacitor hauv koob nrog txhua tus "siab-zaus" hais lus los ua lub lim dej siab.
Xaiv qhov system impedance
Yog hais tias txhua tus hais lus txuas nrog rau qhov sib npaug thiab muaj qhov cuam tshuam tib yam, ces kev xam cov acoustic crossover yog ib qho yooj yim ua. Cias faib cov impedance los ntawm cov neeg hais lus nyob rau hauv parallel.
Piv txwv 1: Plaub 8 ohm hais lus, kev sib txuas sib txuas: 8 / 4=2 ohms. Piv txwv 2: Ob tug 4 ohm hais lus, parallel circuit: 4 / 2=2 ohms.
Txhawm rau xam cov neeg hais lus sib txuas ua ke tab sis muaj qhov sib txawv impedances, cov qauv hauv qab no siv:
R total=1/(1/r1+1/r2+…..).
Qhov tseeb, qhov tseeb suav ntawm lub kaw lus suab yog txheej txheem empirical nyuaj heev. Txhawm rau ua kom yooj yim dua, muaj ntau lub tshuab xam zauv online rau tus neeg hais lus crossover hauv is taws nem, xws li lub tshuab xam zauv cais rau 2, 3, thiab 4 tus neeg hais lus txuas nrog tib lub sijhawm, nrog rau cov tshuab xam zauv uas tuaj yeem siv rau ntau qhov kev sib txuas / sib txuas. Txhawm rau ua qhov no, koj yuav tsum nkag mus rau qhov impedance ntawm txhua tus neeg hais lus hauv cov squares dawb ntawm lub laij lej sib raug. Tag nrho impedance rau cov neeg hais lus txuas nrog nyob rau hauv parallel yuav raug txiav txim. Thiab kuj yog ib feem pua yog xam rau txhua tus hais lus.
Cov zaub yuav qhia tias lub zog tso zis ntawm lub tshuab hluav taws xob faib li cas ntawm cov neeg hais lus. Thaum siv ua ke nrog txawv impedanceKev sib faib fais fab yuav raug suav nrog.
Yog tias muaj ib tus neeg tsav tsheb uas tuaj yeem yooj yim thiab raug rov ua dua tshiab ntawm tag nrho cov suab, yuav tsis tas yuav siv crossover. Qhov laj thawj tseem ceeb yog tias ntau tus neeg tsav tsheb feem ntau yuav tsum tau npog tag nrho cov spectrum ntawm lub suab. Nws tsis tuaj yeem ua rau tus neeg tsav tsheb muaj peev xwm tsim tau ob qho tib si siab thiab qis zaus tib lub sijhawm. Ntau hom kev tsav tsheb yog tsim los ua haujlwm zoo hauv ntau qhov sib txawv. Kev siv crossover pab tswj kev ua haujlwm ntawm cov tsav tsheb sib txawv.
