There are also different vowels and seed mantras that you can listen to. You can also sing and chant with your own voice to balance the energy flow in your solar plexus chakra. The vibration of your own voice infused with intention is a very powerful sound healing tool.
In the easter part of the world the vibration of each chakras is associated with their Beeja or seed mantras. And in the west each chakra is associated with a vowel.
A seed mantra is a one-word mantra used to strengthen the energy system of the body. The seed syllable used for the sacral chakra is RAM (Pronounced as RAHM, or RUM). The sound and frequency of RAM will assist in strengthening the abdominal organs in your body.
The vowel associated with the solar plexus chakra is OH.
To experience an internal sound bath try to hold and extend the sound OH. Notice any internal sensations.

Introduction To Your Chakras And Healing Them Through Sound
When you expose your body to sounds with specific frequencies that vibrate within the optimum range of vibration in each chakra, your chakra will realign with the frequency it is exposed to. This phenomenon is known as harmonic resonance. When we are in resonance, we are in balance.