Buku Loyamba la Bose QuietComfort 20 (QC-20) Mafoni

by Brent Butterworth

Ojambula ambiri opanga mafilimu amapereka mafilimu ammutu / makutu ndi chipangizo chamakono (ANC). Izi ndi zabwino kwa anthu omwe amamvetsera nyimbo kapena amawonera mavidiyo kumalo osangalala komanso / kapena poyenda. Komabe, sikuti onse a ANC adalengedwa chimodzimodzi. Timayang'anitsitsa momwe Bose QuietComfort 20 (QC-20) akumvetsera phokoso lamakutu akulira.

Bose QuietComfort 20 Njira

Kuzindikira kwa QC-20, kumayesedwa ndi chizindikiro cha 1 mW pa 32 ohms, ndi kokwanira kuti mutenge mwapamwamba kuchokera ku chipangizo china chilichonse. Bose Corporation

Tinayesa ntchito ya QC-20 pogwiritsa ntchito simulator GRAS 43AG / masaya, analyzer audio Clio FW, software TrueRTA makompyuta lapakompyuta ndi interface M-Audio MobilePre USB, komanso Musical Fidelity V-Can pamutu amplifier. (Sitimakonda kugwiritsa ntchito khutu / masaya tamulator kuti muyese makutu a makutu , koma chifukwa cha mawonekedwe a silicon a QC-20, sizinagwirizane ndi makina opanga GRAS RA0045 omwe amagwiritsidwa ntchito poyeza mumakutu.)

Miyesoyi inalembedwa pakhomo lolowera pakhomo (EEP), pafupifupi malo omwe ali pakati pa malo othawa malo pamene mutsegula chitseko chanu. Tinagwiritsira ntchito mawonekedwe a 43AG kuti titsimikize chisindikizo chabwino cha sewero pa simulator komanso zotsatira zake zonse. Tawonani kuti kupyola muyeso kwa EEP, sitigwiritsa ntchito malo ochepa kapena mapiritsi ena. (Kafukufuku wina wasankha kutsimikizirika kwa zowonongeka, ndipo mpaka malonda akuvomerezana pa kafukufuku wabwino, wowonjezera kafukufuku, timakonda kusonyeza deta zakuda.)

Kuzindikira kwa QC-20, kumayesedwa ndi chizindikiro cha 1 mW pa 32 ohms (chiwerengero cha impedance chiwerengero cha internally-amplified headphones monga QC-20) ndi 104.8 dB, okwera kwambiri kuti atenge mwapamwamba kuchokera mwina chipangizo chilichonse.

QC-20 Frequency Response

Njira ya kumanzere imayimirira mu buluu, kanema yolondola yomwe imayimiridwa mufiira. Brent Butterworth

Kuwonekera kwafupipafupi kwa QC-20 kumanzere (buluu) ndi kumanja (ofiira) njira, mayeso oyesedwa omwe amapezeka pa 94 dB @ 500 Hz. Palibe chikhalidwe cha zomwe zimakhala "zabwino" kawirikawiri mayankho pamutu, ndipo chifukwa chakuti psychoacoustics ndi yovuta komanso maonekedwe amasiyana, mgwirizano pakati pa zolinga zowonetsera zolinga ndi maonekedwe omvera nthawi zina siziwonekera.

Komabe, tchatichi chimakulolani kuti mufanizire zitsanzo moyenera. QC-20 ikuwonetsa kuchepa kwapang'ono kusiyana ndi zambiri m'makutu, zomwe zimakhala ndi ziphuphu m'munsi mwazomwe zikuzungulira kuzungulira 100 Hz. Zimasonyezanso yankho lapadera kwambiri, lomwe liri ndi mphamvu zambiri pakati pa 2 ndi 10 kHz.

QC-20 Frequency Response, phokoso loletsa ndi kuchotsa

Yankho liri chimodzimodzi mu njira ziwiri za QC-20. Brent Butterworth

Kuwonekera kwafupipafupi kwa QC-20, kanjira yolondola, phokoso lachisangalalo ((wofiira) ndikuchotsa (yellow trace). Monga mukuonera, yankho liri chimodzimodzi m'ma modes onsewa. Izi ndi zotsatira zabwino zomwe takhala tikuziwona pa yeseso ili. Kupweteka kwa mutu uliwonse kumayesedwa kusintha kwake kuyankhidwa pang'ono pokhapokha phokoso likuchotsedwa; nthawi zina kusintha kwakumveka ndi kodabwitsa (ndikukwiyitsa).

QC-20 Zowonongeka Kwambiri

Mitsinje yayitali ya buluu imasonyeza kusamba. Brent Butterworth

Chiwonetsero cha mapulaneti (maporopo) a QC-20, njira yoyenera. Mizere yayitali ya buluu imasonyeza kuwonetserana, komwe kawirikawiri sikuyenera. Osadandaula zambiri za apa. Chokhacho, chochepa kwambiri (ndipo mwinamwake inaudible) chimasokoneza pafupifupi 2.3 kHz.

QC-20 Frequency Response, 5 vs. 75 ohms source impedance

QC-20 imagwira ntchito bwino ndi otsika ndi apamwamba kwambiri amplifiers. Brent Butterworth

Kuwonekera kwafupipafupi kwa QC-20, njira yoyenera, podyetsedwa ndi amphamvu (Musical Fidelity V-Can) ndi 5 ohms output impedance (red trace), ndi 75 ohms output impedance (green trace). Momwemo, mizere iyenera kugwirizana mwangwiro, ndipo apa iwo amachita; zomwe kawirikawiri zimakhala ndi internally amplified headphones monga QC-20. Choncho, machitidwe a QC-20 ndi ma tonal balance sangasinthe ngati mumagwiritsa ntchito makutu apamwamba kwambiri, monga omwe amamangidwa pamapulogalamu ambiri ndi mafoni otsika mtengo.

QC-20 Distortion

Kusokonezeka kwa QC-20 ndi kotsika kwambiri. Brent Butterworth

Kusiyana kwa harmonic (THD) ya QC-20, kanjira yolondola, yoyezedwa pa mayeso a 100 dBA. M'munsimu mzerewu uli pa tchati, ndi bwino. Momwemo zikanakhalira pansi malire a tchati. Kuwonjezera pa kakang'ono kakang'ono kotereka kakang'ono ka 4% pa 600 Hz, kusokonezeka kwa QC-20 ndi kotsika kwambiri, makamaka m'munsi.

QC-20 Isolation

Mtsinje umachotsedwa (wobiriwira) ndi pa (wofiira). Brent Butterworth

Kutsekedwa kwa QC-20, kanjira yolondola, ndi kuchotsa phokoso (zobiriwira zobiriwira) ndi kufuula phokoso pa (kufufuza kofiirira). Mipata yomwe ili pansipa 75 dB imasonyeza kuchepa kwa phokoso lakunja (ie, 65 dB pa chithunzicho amatanthawuza kuchepetsa -10 dB kumvekedwe kunja kunja kwa phokoso lakumveka). Pansi mzera uli pa tchati, ndi bwino.

Pa maulendo apamwamba, phokoso lakutsitsa phokoso ndilobwino, pafupi -20 mpaka -25 dB. M'magulu apansi, komwe phokoso la injini ya jet limakhala, zotsatira zake ndi zabwino zomwe tingakumbukire kuyeza, monga -45 dB pa 160 Hz. Izi ndizofanana ndi kuchepetsa kuchepa kwa 96 peresenti. Onani kuti tsatanetsatane wofiira umagwera pansi pa tchati.

QC-20 Impedance

Kufupi ndi kwathunthu kwathunthu, bwino. Brent Butterworth

Kusagwirizana kwa QC-20, njira yoyenera. Kawirikawiri, mpweya wosasinthasintha (mwachitsanzo, wokhazikika) pafupipafupi ndi bwino, koma ndi mpweya wotsika kwambiri wa pulogalamu ya QC-20 mkati mwake, izi siziri zovuta.