When you enter the "sonic inner-verse" one of your greatest powers is mantra.
Mantra breaks down "manas" meaning mind and "tra" meaning instrument, looming or connection, which all together basically implies using the mind as an instrument or I've also heard that its connecting or looming the mind to the heart by use of the words, mouth, lips and tongue. Mantra can be be audible or inaudible and both practices have validity and work differently for everyone. All sound is divine and shakti however, sanskrit has a magic quality to it, if only because it was carefully created with the sonic universe in mind. Each syllable in the sanskrit language represents a deity or an aspect of ourselves.
Our bodies may feel like unconscious matter sometimes however, its the vessel for our personal sonic inner-verse. Our thoughts affect its make-up as well as a steady mantra practice can even heal our bodies.
If you master OM you master mantra because OM is usually in all mantras and has all aspects of waking, sleeping and dreaming energies within it as well as past, present and future, all encompassing. However, since we as a human race has put so much meaning in certain phrases and words they are almost as potent as OM and could work better for you depending on what resonates in your sonic inner-verse. An example is "thank you".... say this and send its vibrations through your being clearing any blockages and channels. Another auspicious mantra, that is very powerful when chanted aloud is "Om Namah Shivya".... chant it as if you are whispering it to yourself at whatever pace you can sustain, you will feel something inside you open and into that void you may wish to drop a wish to your deepest self.
Your complete Sonic Inner-verse is a reflection of the greater Sonic Universe.