player : kmplayer 3.9.3.1358 (inactive in mpc-HC)
video card : nvidia
2010/04/04
A Short Introduction to Numerical Analysis
-- 2007/05/22 bbs backup --
The extreme difficulty of obtaining solutions by conventional mathematical
analysis has led in the past to the use of highly unrealistic models simply
because they led to equations that could be solved. In fact, the applied
mathematician has been engaged in a continual tussle with his conscience to
decide how far he could go in the direction of distorting his model in order
to make the equations tractable. The point is well made in the ancient jest
about the examination question that began 'An elephant whose mass can be
neglected...'
- M. V. Wilkes
A Short Introduction to Numerical Analysis
The extreme difficulty of obtaining solutions by conventional mathematical
analysis has led in the past to the use of highly unrealistic models simply
because they led to equations that could be solved. In fact, the applied
mathematician has been engaged in a continual tussle with his conscience to
decide how far he could go in the direction of distorting his model in order
to make the equations tractable. The point is well made in the ancient jest
about the examination question that began 'An elephant whose mass can be
neglected...'
- M. V. Wilkes
A Short Introduction to Numerical Analysis
2010/03/28
foobar 音質
想把教學貼blog... 註: 後來想一想, 在通原之中, 因為通道而使得訊號有interference, 所以需要equalizer修正, 使得sample時旁邊的訊號影響更小, sample值才正確 dsp之中equalizer是否也是修正經過之前虛擬通道, filter造成訊號間互相的影響呢 通原是用delay*coef相加來做EQ(當然是比較理想和簡單的系統) 如果考慮 z-trans H = a0+a1z^-1+a2z^-2...(可做initial condition的case) 代e^jw => inv z => h=a0+a1del[x-dx]+a2del[x-2dx]... 對嗎? 再回頭想帶入e^jw後, 就會有harmonic tone, w, 2w, 3w... 乘以係數 所以delay的係數應該跟harmonic tone的係數有關係 就可以解釋為啥equalizer的調節bar是依照頻率排的, 而且是倍數關係 55Hz, 110, 220, 440 ... 77, 156, 311, ... 當然一定有近似 假如我推的沒錯 .... 很爽 $ +/- 是調整音量得快捷鍵 單位是dB, 真專業 $ convolver 是迴旋混音器-> 看到這個字就想到convolution 好 反正有impulse response的檔案可以找 可以模擬真空管的效果 一個檔案代表一種音響?? 猜測他用impulse response的目的是模擬一個filter 也就是真空管音響的filter 經過filter 自然要做convolution equalizer 是可以調整不同頻率的gain 例如所謂重低音就是把低頻gain調高 可以抓到一些檔案(preset 看字面就了解了吧) 有不同的風格 例如家庭劇院 要試聽後才知道 不是只有引入套件那是沒什麼效果的 也可以手動調 $ 改skin的話 可以裝 foo_syfm 的 plug-in 再去抓 .fb2k 檔 或是自己寫 或是 foo_looks $ foo_unpack 可以直接從壓縮檔放音樂 # 不知道順序有沒有關係 LTI system 沒關係 但這是嗎?
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