सप्तदशोऽध्यायः Types of Pranav (Aum, OM), Shiv Puran Chapter 17: continued

दीर्घप्रणवमेवं हि योगिनामेव हृद्गतम् |
मकारं तंत्रितत्त्वं हि ह्रस्वप्रणव उच्यते || 14 ||

 

Only the long Pranava (Om) has gone into the hearts of Yogis. The M-sound (of the Om) independently is called the short Pranava.