- #2396 [shungyan], 17-05-16 20:06
- #2395 [mark1], 17-05-16 19:51.
- #2394 [mark1], 17-05-16 19:49即是前設了最大聲是105dB,,才計出75dB動態,,那麽就完全沒有甚麽代表性了,,,
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- #2393 [shungyan], 17-05-16 19:31喇叭呢, 個75db 係example 嚟唧! 而其limitation 同音盤設計有關我估! 例如對喇叭最大聲都係得105db, 而用最小能今到佢郁嘅能量輸入下, 佢一郁最小都會發出30db 嘅聲, 咁個dynamic range 咪75db gra.
- #2392 [mark1], 17-05-16 19:19所以睇唔明幅圖想表達甚麽,如師兄所指的noise floor,只是計器材的底噪,,那麼幅圖裡的喇叭是無源的,,理論上應該是沒有底噪的,,那麽75dB動態範圍又是基於甚麽標凖計算出來,,,
- #2391 [shungyan], 17-05-16 19:05只講specs 就唔計! 因為90db只係講cd 碟呢個軟件本身個specs所能容納嘅能耐! 而成件事要得到90db dynamic range 嘅音樂, 錄存播都要相當ideal 至得! 就好似ching 所講, cd 機本身一大堆週邊線路如analog 放大, 最終去到前级都大打折扣! 都重未計其他component 本身個limitation!
最後修改時間: 2017-05-16 19:10:24 - #2390 [mark1], 17-05-16 18:44CD機的模擬放大部份不需要計嗎?
- #2389 [shungyan], 17-05-16 18:23Mark ching, 唔係好明你話同一幅畫, 這樣分開計... 所指係乜?
Cd 90db s/n ratio 中, 個系統係只計ideal adc 入面個noise floor. - #2388 [mark1], 17-05-16 18:11同一幅圖,,這樣分開計,,就完全冇説服力了,,,
- #2387 [shungyan], 17-05-16 17:39Cd 個90db dynmamic range 係spec. Noise floor 係計adc only
- #2386 [mark1], 17-05-16 17:06#2364 >>> 我感覺每次聽都興奮,那高低起伏同金屬撞激,澎湃低頻訴說死亡恐怖!
咁堅 , 咁要試埋呢隻
低音更勁 , , , 更打心口 , , , 金屬撞激指數爆燈 - #2385 [mark1], 17-05-16 16:55如果計埋noise floor,CD係90dB dynamic range,真係唔知點計出來,,幅圖真係耐人尋味,,,
- #2384 [shungyan], 17-05-16 16:45有D野quantization. 同bit depth 有關, 有條數base on 一個ideal 嘅adc 個noise error 係1/2 bit. 所以16 bit 最盡可以有log65536 x2. 係9.633B。 即96.33db
- #2383 [mark1], 17-05-16 15:26.
- #2382 [mark1], 17-05-16 13:57明白,cd機也有opamp,為何是90dB,,,
- #2381 [shungyan], 17-05-16 13:24Ching,
大概係條公式(fix gain 為例) 講一部amp 個dynamic range 係等於其能放大於某一個gain 時之最大signal over 其當時嘅noise floor! 即係部amp 能做到最好嘅s/n ratio. 變相係有效放大能力!
最後修改時間: 2017-05-16 13:34:03 - #2380 [mark1], 17-05-16 12:44睇唔明,即是想表達甚麼?
- #2379 [shungyan], 17-05-16 12:22Ching, web search! 對否?
Fixed gain case: Dynamic range = (biggest signal at some gain x / noise floor at same gain x)
Variable gain case: Dynamic range = (biggest signal at minimum gain / noise floor at maximum gain) - #2378 [mark1], 17-05-16 12:08amp gain並不等於amp dynamic range,,,
- #2377 [shungyan], 17-05-16 11:52Ching, 我認為都係講部amp signal 放大嘅個能力! 有錯唔好打面!
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所以我認為係一個例子而已! 但當上限係130db時, 最細聲又係幾多呢(冇聲唔計)? 可能係一係冇聲出, 一出就60db 都未定woo. 到時個dynamic range 得70db ja woo.