bottom heading meaning in English

底部导洞
底导洞法
底导坑
底道坑
下部平巷

Bottom head resonant head
桶鼓底鼓的底皮
This directs a waveform toward the floor , which bounces back up and interacts with the vibrating bottom head to cancel or emphasize certain frequencies
这个直接向着地板去的声波将被反弹上来并且会对底面鼓皮的震动造成相消或加重某些频率的影响。
Consider a floor tom mounted in a standard vertical orientation : with a hardwood floor , when the player hits the drum the bottom head vibrates sympathetically
考虑到落地桶鼓是在标准垂直方向上：如用木地板，当鼓手击鼓，下面的鼓皮也要跟随着震动。
With the tom set up vertically , sound waves hit the floor and bounce back into the bottom head . angling a tom slightly causes sound waves to scatter , and diffuses them
落地桶鼓垂直摆放，声波碰到地板反射回底鼓皮。轻微调节落地桶鼓的摆放角度使声波散射和漫反射。