Ghi ch\u00fa: T\u00e0i li\u1ec7u tr\u00edch d\u1eabn<\/p>\n\n\n\n
Ch\u00fang ta v\u1eabn th\u01b0\u1eddng nghe th\u1ea5y ti\u1ebfng vang, \u00e2m thanh ph\u1ea3n l\u1ea1i khi \u0111i v\u00e0o hang \u0111\u1ed9ng, v\u00e1ch n\u00fai. \u0110i\u1ec1u n\u00e0y c\u00f3 \u0111\u01b0\u1ee3c coi l\u00e0 \u00e2m thanh truy\u1ec1n \u0111i t\u1eeb ngu\u1ed3n \u00e2m \u0111\u1ebfn tai ta hay kh\u00f4ng? T\u1ea1i sao l\u1ea1i x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng n\u00e0y? Ph\u1ea3n x\u1ea1 ti\u1ebfng vang ch\u00ednh l\u00e0 nh\u1eefng \u00e2m thanh m\u00e0 ch\u00fang ta th\u01b0\u1eddng nghe th\u1ea5y trong tr\u01b0\u1eddng h\u1ee3p n\u00e0y. \u0110\u00e2y l\u00e0 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng kh\u00e1 ph\u1ed5 bi\u1ebfn trong cu\u1ed9c s\u1ed1ng th\u01b0\u1eddng ng\u00e0y. B\u00e0i vi\u1ebft ng\u00e0y h\u00f4m nay, ch\u00fang ta h\u00e3y c\u00f9ng nhau t\u00ecm hi\u1ec3u v\u1ec1 ch\u1ee7 \u0111\u1ec1 n\u00e0y nh\u00e9!<\/p>\n\n\n\n
Ti\u1ebfng vang l\u00e0 g\u00ec?<\/p>\n\n\n\n
\u0110\u1ed9 to c\u1ee7a \u00e2m<\/p>\n\n\n\n
\u0110\u1ec3 hi\u1ec3u h\u01a1n v\u1ec1 ph\u1ea3n x\u1ea1 ti\u1ebfng vang, ch\u00fang ta c\u1ea7n ph\u1ea3i bi\u1ebft \u00e2m thanh t\u1eeb \u0111\u00e2u m\u00e0 c\u00f3. \u00c2m thanh \u0111\u01b0\u1ee3c sinh ra t\u1eeb nh\u1eefng bi\u00ean \u0111\u1ed9 dao \u0111\u1ed9ng c\u1ee7a ngu\u1ed3n \u00e2m. Bi\u00ean \u0111\u1ed9 dao \u0111\u1ed9ng ch\u00ednh l\u00e0 s\u1ef1 ch\u00eanh l\u1ec7ch l\u1edbn nh\u1ea5t c\u1ee7a v\u1eadt so v\u1edbi v\u1ecb tr\u00ed c\u00e2n b\u1eb1ng. Bi\u00ean \u0111\u1ed9 giao \u0111\u1ed9ng c\u00e0ng l\u1edbn th\u00ec \u00e2m thanh \u0111\u01b0\u1ee3c truy\u1ec1n \u0111i c\u00e0ng to. \u0110\u00e2y ch\u00ednh l\u00e0 s\u1ef1 xu\u1ea5t ph\u00e1t c\u1ee7a \u00e2m thanh truy\u1ec1n \u0111i t\u1eeb ngu\u1ed3n \u00e2m. \u0110\u1ed9 to c\u1ee7a \u00e2m s\u1ebd quy\u1ebft \u0111\u1ecbnh \u00e2m thanh truy\u1ec1n \u0111i \u0111\u01b0\u1ee3c bao xa. N\u1ebfu \u0111\u1ed9 to c\u1ee7a \u00e2m nh\u1ecf th\u00ec \u00e2m thanh ch\u1ec9 c\u00f3 th\u1ec3 truy\u1ec1n \u0111i g\u1ea7n v\u00e0 kh\u00f4ng th\u1ec3 x\u1ea3y ra ph\u1ea3n x\u1ea1 ti\u1ebfng vang.<\/p>\n\n\n\n
N\u00f3i c\u00e1ch kh\u00e1c, khi bi\u00ean \u0111\u1ed9 dao \u0111\u1ed9ng l\u1edbn, \u00e2m thanh truy\u1ec1n \u0111i l\u1edbn th\u00ec c\u00f3 th\u1ec3 x\u1ea3y ra ph\u1ea3n x\u1ea1 ti\u1ebfng vang. \u0110\u1ed9 to c\u1ee7a \u00e2m \u0111\u01b0\u1ee3c \u0111o b\u1eb1ng \u0111\u01a1n v\u1ecb \u0111\u1ec1 \u2013 xi \u2013 ben hay c\u00f2n \u0111\u01b0\u1ee3c k\u00ed hi\u1ec7u l\u00e0 dB. \u0110\u00e2y ch\u00ednh l\u00e0 k\u00ed hi\u1ec7u \u0111\u01b0\u1ee3c quy \u01b0\u1edbc \u0111\u1ec3 \u0111o \u0111\u1ed9 l\u1edbn c\u1ee7a \u00e2m thanh. Ngo\u00e0i dB c\u00f2n c\u00f3 nhi\u1ec1u \u0111\u01a1n v\u1ecb kh\u00e1c \u0111\u1ec3 \u0111o \u0111\u1ed9 l\u1edbn c\u1ee7a \u00e2m thanh. Tuy nhi\u00ean, trong ch\u01b0\u01a1ng tr\u00ecnh v\u1eadt l\u00fd l\u1edbp 7, c\u00e1c em s\u1ebd d\u00f9ng nhi\u1ec1u \u0111\u1ebfn \u0111\u01a1n v\u1ecb n\u00e0y. Ph\u1ea3n x\u1ea1 ti\u1ebfng vang c\u0169ng s\u1eed d\u1ee5ng \u0111\u01a1n v\u1ecb n\u00e0y \u0111\u1ec3 \u0111o \u0111\u1ed9 l\u1edbn c\u1ee7a \u00e2m thanh ph\u1ea3n l\u1ea1i. C\u00e1c em n\u00ean nh\u1edb \u0111\u1ebfn \u0111\u01a1n v\u1ecb n\u00e0y \u0111\u1ec3 c\u00f3 th\u1ec3 t\u00ednh to\u00e1n \u00e2m thanh ch\u00ednh x\u00e1c.<\/p>\n\n\n\n
M\u00f4i tr\u01b0\u1eddng truy\u1ec1n \u00e2m<\/p>\n\n\n\n
N\u1ebfu c\u00e1c em \u0111\u00e3 t\u00ecm hi\u1ec3u qua v\u1ec1 \u00e2m thanh. Ch\u1eafc h\u1eb3n c\u00e1c em s\u1ebd bi\u1ebft kh\u00f4ng ph\u1ea3i m\u00f4i tr\u01b0\u1eddng n\u00e0o c\u0169ng c\u00f3 th\u1ec3 \u0111\u1ec3 \u00e2m thanh truy\u1ec1n \u0111i. \u0110\u00e2y ch\u00ednh l\u00e0 l\u00fd do ch\u00fang t\u00f4i quy\u1ebft \u0111\u1ecbnh \u0111em \u0111\u1ebfn cho c\u00e1c em nh\u1eefng th\u00f4ng tin n\u00e0y khi t\u00ecm hi\u1ec3u v\u1ec1 ph\u1ea3n x\u1ea1 ti\u1ebfng vang. \u00c2m thanh ch\u1ec9 c\u00f3 th\u1ec3 truy\u1ec1n \u0111i v\u00e0 ph\u1ea3n x\u1ea1 l\u1ea1i trong m\u00f4i tr\u01b0\u1eddng truy\u1ec1n \u00e2m. C\u00e1c m\u00f4i tr\u01b0\u1eddng cho ph\u00e9p \u00e2m thanh \u0111i qua nh\u01b0 r\u1eafn, l\u1ecfng, kh\u00ed m\u1edbi c\u00f3 th\u1ec3 xu\u1ea5t hi\u1ec7n \u0111i\u1ec1u n\u00e0y. M\u00f4i tr\u01b0\u1eddng kh\u00f4ng kh\u00ed l\u00e0 n\u01a1i d\u1ec5 x\u1ea3y ra s\u1ef1 ph\u1ea3n x\u1ea1 \u00e2m thanh nh\u1ea5t.<\/p>\n\n\n\n
Ch\u00fang ta th\u01b0\u1eddng th\u1ea5y nh\u1eefng \u00e2m thanh vang v\u1ecdng l\u1ea1i khi \u0111i v\u00e0o hang n\u00fai. \u00c2m thanh ch\u00fang ta n\u00f3i truy\u1ec1n \u0111i trong kh\u00f4ng kh\u00ed, sau \u0111\u00f3 v\u1ecdng l\u1ea1i. V\u1eadn t\u1ed1c truy\u1ec1n \u00e2m trong c\u00e1c m\u00f4i tr\u01b0\u1eddng l\u00e0 kh\u00e1c nhau. \u0110i\u1ec1u n\u00e0y c\u0169ng quy\u1ebft \u0111\u1ecbnh \u0111\u1ebfn vi\u1ec7c ph\u1ea3n x\u1ea1 ti\u1ebfng vang l\u00e0 nhanh hay ch\u1eadm. V\u00ec x\u00e9t tr\u00ean th\u1ef1c t\u1ebf, \u00e2m thanh v\u1eabn ph\u1ea3i truy\u1ec1n \u0111i m\u1edbi c\u00f3 th\u1ec3 v\u1ecdng l\u1ea1i. V\u1eadn t\u1ed1c \u00e2m thanh truy\u1ec1n \u0111i v\u00e0 v\u1ecdng l\u1ea1i ph\u1ee5 thu\u1ed9c v\u00e0o v\u1eadn t\u1ed1c c\u1ee7a m\u00f4i tr\u01b0\u1eddng truy\u1ec1n \u00e2m. C\u00e1c em n\u00ean nh\u1edb v\u1eadn t\u1ed1c trong t\u1eebng m\u00f4i tr\u01b0\u1eddng truy\u1ec1n \u00e2m \u0111\u1ec3 l\u00e0m b\u00e0i m\u1ed9t c\u00e1ch ch\u00ednh x\u00e1c nh\u1ea5t.<\/p>\n\n\n\n
Ph\u1ea3n x\u1ea1 ti\u1ebfng vang l\u00e0 g\u00ec?<\/p>\n\n\n\n
Nh\u01b0 ch\u00fang ta \u0111\u00e3 \u0111\u1ec1 c\u1eadp \u0111\u1ebfn ph\u00eda tr\u00ean, \u00e2m thanh truy\u1ec1n \u0111i sau \u0111\u00f3 v\u1ecdng l\u1ea1i g\u1ecdi l\u00e0 ph\u1ea3n x\u1ea1 ti\u1ebfng vang. Tuy nhi\u00ean, \u0111i\u1ec1u n\u00e0y l\u00e0 ch\u01b0a \u0111\u1ee7 v\u1edbi \u0111\u1ecbnh ngh\u0129a. \u00c2m thanh sau khi truy\u1ec1n \u0111i, g\u1eb7p ph\u1ea3i m\u1eb7t ch\u1eafn, vang v\u1ecdng l\u1ea1i m\u1edbi \u0111\u01b0\u1ee3c t\u00ednh l\u00e0 ph\u1ea3n x\u1ea1 \u00e2m thanh. N\u1ebfu trong m\u00f4i tr\u01b0\u1eddng truy\u1ec1n \u00e2m kh\u00f4ng c\u00f3 m\u1eb7t ch\u1eafn \u00e2m thanh, th\u00ec \u0111i\u1ec1u n\u00e0y s\u1ebd kh\u00f4ng x\u1ea3y ra. V\u00ed d\u1ee5 ch\u00fang ta n\u00f3i chuy\u1ec7n v\u1edbi nhau trong l\u1edbp h\u1ecdc. \u00c2m thanh truy\u1ec1n t\u1eeb ng\u01b0\u1eddi n\u00f3i sang ng\u01b0\u1eddi nghe m\u00e0 ho\u00e0n to\u00e0n kh\u00f4ng c\u00f3 m\u1eb7t ch\u1eafn. Th\u00ec s\u1ebd kh\u00f4ng x\u1ea3y ra hi\u1ec7n t\u01b0\u1ee3ng ph\u1ea3n x\u1ea1 c\u1ee7a \u00e2m thanh. V\u1eady trong nh\u1eefng tr\u01b0\u1eddng h\u1ee3p n\u00e0o th\u00ec \u00e2m thanh c\u00f3 th\u1ec3 vang v\u1ecdng l\u1ea1i?<\/p>\n\n\n\n
Tr\u00ean th\u1ef1c t\u1ebf, ch\u00fang ta g\u1eb7p ph\u1ea3n x\u1ea1 ti\u1ebfng vang trong hang \u0111\u1ed9ng, v\u00e1ch n\u00fai. \u1ede m\u1ed9t s\u1ed1 c\u0103n ph\u00f2ng, ng\u00f4i nh\u00e0 tr\u1ed1ng, ch\u00fang ta c\u0169ng c\u00f3 th\u1ec3 th\u1ea5y \u0111\u01b0\u1ee3c \u0111i\u1ec1u n\u00e0y. \u0110\u00f3 l\u00e0 do trong c\u00e1c kh\u00f4ng gian n\u00e0y xu\u1ea5t hi\u1ec7n m\u1eb7t ch\u1eafn \u00e2m thanh. M\u1eb7t ch\u1eafn \u00e2m thanh trong hang \u0111\u1ed9ng hay v\u00e1ch n\u00fai ch\u00ednh l\u00e0 nh\u1eefng v\u00e1ch \u0111\u00e1 d\u1ef1ng \u0111\u1ee9ng. \u00c2m thanh sau khi truy\u1ec1n \u0111i g\u1eb7p ph\u1ea3i nh\u1eefng v\u00e1ch ch\u1eafn n\u00e0y s\u1ebd vang v\u1ecdng l\u1ea1i tai ta. \u0110\u00e2y l\u00e0 m\u1ed9t hi\u1ec7n t\u01b0\u1ee3ng h\u1ebft s\u1ee9c b\u00ecnh th\u01b0\u1eddng v\u00e0 c\u00f3 th\u1ec3 g\u1eb7p r\u1ea5t nhi\u1ec1u trong cu\u1ed9c s\u1ed1ng. Hi\u1ec3u \u0111\u01b0\u1ee3c ki\u1ebfn th\u1ee9c n\u00e0y, c\u00e1c em ho\u00e0n to\u00e0n c\u00f3 th\u1ec3 t\u1ef1 l\u00fd gi\u1ea3i.<\/p>\n\n\n\n
\u0110\u1ed9 quan tr\u1ecdng c\u1ee7a ph\u1ea3n x\u1ea1 \u00e2m ti\u1ebfng vang<\/p>\n\n\n\n
Theo nh\u1eefng nghi\u00ean c\u1ee9u c\u1ee7a c\u00e1c nh\u00e0 v\u1eadt l\u00fd h\u1ecdc cho th\u1ea5y. \u00c2m ph\u1ea3n x\u1ea1 ch\u00fang ta nghe \u0111\u01b0\u1ee3c c\u00e1ch \u00e2m tr\u1ef1c ti\u1ebfp \u00edt nh\u1ea5t l\u00e0 1\/15 gi\u00e2y s\u1ebd \u0111\u01b0\u1ee3c t\u00ednh l\u00e0 ti\u1ebfng vang. Ngo\u00e0i ra c\u00e1c \u00e2m thanh ch\u00fang ta nghe \u0111\u01b0\u1ee3c nhanh h\u01a1n 1\/15s th\u00ec \u0111\u00f3 l\u00e0 \u00e2m thanh th\u00f4ng th\u01b0\u1eddng. Tai c\u1ee7a ch\u00fang ta v\u1eabn c\u00f3 th\u1ec3 nghe th\u1ea5y nh\u1eefng \u00e2m thanh n\u00e0y nh\u01b0ng kh\u00f4ng \u0111\u01b0\u1ee3c t\u00ednh l\u00e0 ti\u1ebfng vang. Ph\u1ea3n x\u1ea1 ti\u1ebfng vang ch\u1ec9 xu\u1ea5t hi\u1ec7n sau 1\/15s ho\u1eb7c c\u00f3 th\u1ec3 l\u00e2u h\u01a1n. \u0110\u00e2y ch\u00ednh l\u00e0 c\u00e1ch ch\u00fang ta nh\u1eadn bi\u1ebft ti\u1ebfng vang trong cu\u1ed9c s\u1ed1ng h\u1eb1ng ng\u00e0y.<\/p>\n\n\n\n
V\u1eadt ph\u1ea3n x\u1ea1 \u00e2m t\u1ed1t, v\u1eadt ph\u1ea3n x\u1ea1 \u00e2m k\u00e9m<\/p>\n\n\n\n
Ch\u00fang ta bi\u1ebft r\u1eb1ng, khi \u00e2m thanh g\u1eb7p ph\u1ea3i m\u1eb7t ch\u1eafn m\u1edbi ph\u1ea3n x\u1ea1 ng\u01b0\u1ee3c l\u1ea1i. V\u1eady nh\u1eefng m\u1eb7t ch\u1eafn \u00e2m thanh nh\u01b0 th\u1ebf n\u00e0o th\u00ec c\u00f3 th\u1ec3 nghe \u0111\u01b0\u1ee3c ti\u1ebfng vang. V\u1eadt ph\u1ea3n x\u1ea1 \u00e2m t\u1ed1t v\u00e0 v\u1eadt ph\u1ea3n x\u1ea1 \u00e2m k\u00e9m s\u1ebd quy\u1ebft \u0111\u1ecbnh \u0111i\u1ec1u n\u00e0y. Nh\u1eefng v\u1eadt ph\u1ea3n x\u1ea1 \u00e2m t\u1ed1t th\u00ec ch\u00fang ta c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng nghe th\u1ea5y ti\u1ebfng vang. C\u00f2n \u0111\u1ed1i v\u1edbi nh\u1eefng v\u1eadt ph\u1ea3n x\u1ea1 \u00e2m k\u00e9m, ch\u00fang ta s\u1ebd kh\u00f4ng th\u1ec3 th\u1ea5y ph\u1ea3n x\u1ea1 ti\u1ebfng vang.<\/p>\n\n\n\n
T\u1eeb nh\u1eefng th\u00ed nghi\u1ec7m v\u1eadt l\u00fd cho th\u1ea5y, v\u1eadt c\u00f3 b\u1ec1 m\u1eb7t nh\u1eb5n s\u1ebd ph\u1ea3n x\u1ea1 \u00e2m t\u1ed1t h\u01a1n c\u1ea3. V\u00ed d\u1ee5 nh\u01b0 b\u1ee9c t\u01b0\u1eddng ph\u1eb3ng l\u1ef3, v\u00e1ch \u0111\u00e1 th\u1eb3ng d\u1ef1ng \u0111\u1ee9ng, m\u1eb7t g\u01b0\u01a1ng, m\u1eb7t \u0111\u00e1 hoa,\u2026 \u0110\u00e2y c\u0169ng ch\u00ednh l\u00e0 l\u00fd do v\u00ec sao, khi ch\u00fang ta \u0111\u1ee9ng trong nh\u1eefng ng\u00f4i nh\u00e0 m\u1edbi x\u00e2y. Ch\u00fang ta n\u00f3i th\u01b0\u1eddng s\u1ebd nghe \u0111\u01b0\u1ee3c ti\u1ebfng v\u1ecdng l\u1ea1i. B\u1edfi \u00e2m thanh t\u1eeb ch\u00fang ta truy\u1ec1n \u0111i trong kh\u00f4ng kh\u00ed, sau \u0111\u00f3 g\u1eb7p b\u1ee9c t\u01b0\u1eddng. \u00c2m thanh n\u00e0y s\u1ebd ph\u1ea3n x\u1ea1 l\u1ea1i v\u00e0 truy\u1ec1n \u0111\u1ebfn tai ta.<\/p>\n\n\n\n
Tr\u00e1i l\u1ea1i, v\u1edbi nh\u1eefng v\u1eadt c\u00f3 b\u1ec1 m\u1eb7t x\u00f9 x\u00ec, g\u1ed3 gh\u1ec1 th\u01b0\u1eddng s\u1ebd ph\u1ea3n x\u1ea1 \u00e2m k\u00e9m h\u01a1n. Ng\u01b0\u1eddi ta c\u00f2n g\u1ecdi nh\u1eefng v\u1eadt n\u00e0y l\u00e0 v\u1eadt c\u00e1ch \u00e2m, v\u1eadt h\u1ea5p th\u1ee5 \u00e2m thanh. \u00c2m thanh th\u00f4ng th\u01b0\u1eddng khi g\u1eb7p nh\u1eefng b\u1ec1 m\u1eb7t nh\u01b0 v\u1eady th\u01b0\u1eddng s\u1ebd kh\u00f4ng th\u1ec3 ph\u1ea3n x\u1ea1 l\u1ea1i. \u00c2m thanh sau khi truy\u1ec1n \u0111i g\u1eb7p ph\u1ea3i b\u1ec1 m\u1eb7t x\u00f9 x\u00ec s\u1ebd tr\u1edf n\u00ean nh\u1ecf h\u01a1n v\u00e0 kh\u00f4ng g\u00e2y ra ti\u1ebfng vang. Nh\u1eefng b\u1ec1 m\u1eb7t nh\u01b0 l\u00e0 mi\u1ebfng x\u1ed1p, \u00e1o len, gh\u1ebf \u0111\u1ec7m m\u00fat, cao su s\u1ebd kh\u00f4ng ph\u1ea3n x\u1ea1 \u00e2m. Ph\u1ea3n x\u1ea1 ti\u1ebfng vang ph\u1ee5 thu\u1ed9c nhi\u1ec1u v\u00e0o b\u1ec1 m\u1eb7t ph\u1ea3n x\u1ea1 quy\u1ebft \u0111\u1ecbnh c\u00f3 ti\u1ebfng vang hay kh\u00f4ng.<\/p>\n\n\n\n
Ki\u1ebfn th\u1ee9c ph\u1ea3n x\u1ea1 \u00e2m ti\u1ebfng vang<\/p>\n\n\n\n
B\u00e0i t\u1eadp v\u1eadn d\u1ee5ng l\u00fd thuy\u1ebft ph\u1ea3n x\u1ea1 ti\u1ebfng vang<\/p>\n\n\n\n