3 sentences

1. 他的嗓音低沉而急切。

   tā de sǎng​yīn dī​chén ér jí​qiè.

   His voice was low and urgent.

   Source: AI Challenger 2017

2. 他的嗓音变得很低沉。

   tā de sǎng​yīn biàn​de hěn dī​chén.

   His voice became very low.

   Source: CCMatrix

3. 他吹了一记低沉的口哨。

   tā chuī le yī jì dī​chén de kǒu​shào.

   He gave a low-pitched whistle.

   Source: AI Challenger 2017