Verse 39

प्रणवादिसमुच्चारात् प्लुतान्ते शून्यभावानात् ।शून्यया परया शक्त्या शून्यताम् एति भैरवि

In plain words

By sounding and the like, by contemplating the void at the end of the prolonged measure, through the supreme that is void you come to voidness, O .