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spatial attributes and reverberation

analysis of perceived spatial attribute

• placement of direct (dry) sound sources

  • angular location

  • distance

    • direct sound level

    • reverberation level

    • distance of microphones

    • room microphones

    • low-pass filtering of close-miked direct sounds

  • spatial extent

• acoustic space and sound stages

  • reverberation decay character

  • spatial extent of the sound stages

  • spaciousness

• overall characteristics of stereo images

  • coherence and relative polarity between channels

  • spatial continuity of a sound image from one loudspeaker to another

basic building blocks of digital reverberation

• time delay

• reverberation

  • decay time: amount of time it takes for a sound to decay 60 dB once it is turned off.

  • delay time

  • pre-delay time: time between the direct sound and the onset of reverberation

  • filter

  • gate: threshold, attack time, hold time, release time, etc.

• digital reverberation presets

  • only a handful of different algorithms for a given type or model of reverberation

  • all of the presets using a given type of algorithm represent identical types of processes

  • pick any preset and start tuning the parameters as opposed to trying to find a preset that will work without any adjustments

• Avid D-Verb

  • user's giude

  • in Pro Tools 9

Technical Ear Trainer: reverberation

注意！每次練習時間請勿過長，建議操作五分鐘即休息五分鐘，連續總計不超過一小時。經常性分散練習效果遠勝於短期性密集練習。聽覺疲乏後若仍持續練習，並無法進步，甚至恐有反效果。

audio sample

• pink noise：較不適合本次練習。

• sound file：請下載本課程第二週介紹之 ITU-R BS.1387 所附音訊檔案，比較同樣參數對不同樣本產生的效果。

practice types

• matching：配對模式，可練習聆聽每個選項的組合，並切換回題目聲音樣本比對異同。

• matching memory：記憶配對模式，題目只能聽一次，訓練記憶準確度。

• absolute identification：鑑定模式，無法聽到作答參數的聲音輸出。

Technical Ear Trainer: mid-side

mid-side matrixing

• not a specific stereo microphone technique here

• phase vs. polarity

• bringing forth components of a sound image that might not otherwise be as audible

  • mid component

    • mid = left + right

    • all components from a stereo mix that are not opposite polarity between the two channels

    • anything common to both channels

    • anything present in only one side

  • side component

    • side = left - right

    • cancel out anything common to both L and R

    • cancel out any signal panned center in a mix

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