最標準的當然是無響室中,但wikipedia這篇也寫著,
Most anechoic chambers are not designed for accurate measurement down to 20 Hz.
無響室很貴,那換個方式,搬到戶外去,嘿,這就只剩下地板,
那,地板的效應呢?
這我之前寫過一篇 http://records2ear.blogspot.tw/2012/03/ ... st_13.html
當然這也是離地板越遠越好,一般喇叭的高度總是會有明顯的中頻梳形濾波效應,
wikipedia這篇寫著
Raising both speaker and microphone on poles has been used as a way of reducing ground effect, and some speaker manufacturers specify a height of 50 feet (15 m) in their measurements.
拉高到15m夠高了吧?這等於22Hz的波長囉~地板效應夠低了
搭一間30m立方的大棚子應該比無響室便宜很多喔...