[填空题]
If you were to build a pip2.w3itrzcr/ rnf gm)zx. **nbe organ with open-tube 9wylyba u.d+:mko 5 v*4nvuz2pipes spanning the range of human hearing (20 Hz to 20 kHz), what would be the range of the lengths 9+wo4.y5d2 *zakulv:y u bn vmof pipes required? $L_{20 Hz}$ = m $L_{20 kHz}$ = $ \times10^{ -3}$m