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recording_outdoor

**This is an old revision of the document!**

Jibber Jabber

The human ear has a large dynamic range in sound reception. The ratio of the sound intensity that causes permanent damage during short exposure to that of the quietest sound that the ear can hear is greater than or equal to 1 trillion (10^{12}). Such large measurement ranges are conveniently expressed in logarithmic scale: the base-10 logarithm of 10^{12} is 12, which is expressed as a sound pressure level of 120 dB re 20 μPa.

16bitをダイナミックレンジに換算すると「2の16乗」で96dBですが、96.1dBでもアウトなので、ふつうは12dBの余裕を持たせます。音楽の場合、演奏のたびに最大音量が10dBくらい上下する可能性があるからです。つまり、16bitで録音した場合、実効的なダイナミックレンジは70dB少々です。

L=log{10}{(Power ratio)}=log{10}{(Amplitude ratio)^{2}}

$10*log_{10}(2^{16})^{2}=96dB$

使用iphone录音

使用iphone的拍摄的视频。很容易有音量超出

iPhone的录音能力

I'm 99.9% sure it's 48kHz, 16-bit Mono (or Stereo if you have a plug-in mic of some sort which supports Stereo). I use the FiRe app which is one of the most comprehensive and professional-geared recording apps, and that's the max it supports. On older iPhones like the 3G I believe it was only 44.1kHz.

参考资料:
* 自然音を録音したいのですが https://oshiete.goo.ne.jp/qa/7636800.html

recording_outdoor.1545463252.txt.gz · Last modified: 2018/12/22 15:20 by admin