彼は自分の品物の値段を下げねばならなかった。

English Translation

He had to reduce the price of his wares.

The TTS audio puts the accent on the first letter of 下げねば, but you should do so on the second letter. Try Google Translate instead. Google TTS sounds natural.

FYI: 下げねばならなかった sounds more suitable for formal writings than 下げなければならなかった, and probably a bit stronger in the nuance of necessity.