( ( ( ( Point ( at ( which ( ( loudness and ) shrillness ) ) ) ) ( of sound ) ) ( become painful ) ) . )
(ROOT (NP (NP (NNP Point)) (PP (IN at) (SBAR (WHNP (WDT which)) (S (VP (VP (VBZ loudness)) (CC and) (VP (VBZ shrillness)))))) (PP (IN of) (NP (NN sound))) (VP (VBN become) (S (ADJP (JJ painful)))) (. .)))
Point at which loudness and shrillness of sound become painful.
(ROOT (S (S (VP (VBN Amplified))) (, ,) (NP (PRP it)) (VP (VBZ becomes) (SBAR (S (NP (NNP louder)) (VP (VBZ happens) (VP (VB do) (NP (DT the) (NN sound)) (PP (IN during) (NP (DT a) (NN resonance)))))))) (. .)))