Mantras can excite the emotions and give suggestions to the mind. Mantras affect both the one who chants them as the one who hears them. The word mantra comes from the Sanskrit "mantrana", which means advice or suggestion. In a sense, every word is a mantra. In our daily life we use words to get everything done, obtain everything we need. Each mantra or word is a sound pattern that suggests to the mind the meanings inherent in it, and the mind immediately responds.
According to Ramana Maharshi, repetition of mantras (japa), with attention directed to the source of the sound, completely engages the mind. This is Tapas (penance). The source is not in the vocal chords alone, but also the idea of the sound is in the mind, whose source is self. Thus the practice of mantra repetition is more than a suggestion, a bit of advice or an idea. It is a means of getting in touch with our self.
Mantras may be used for religious worship, for japa (repetition), for healing, to help spiritual evolution, for purification, for making offerings and in Mantra Yoga. Some mantras are only chants or expressions of nearness to the Divine. But some saints who were inspired by divine love and unshakable faith used these mantras in their own spiritual practice and their followers afterwards started using those mantras, calling them mahamantras or great mantras.
Primarily it is faith which creates the effect of mantras. Melody, intonation, pronunciation, whether silently or aloud, all are important in the recitation of mantras. Moreover, the beat cycle in which mantras are recited is important, but it changes according to the state of consciousness of the one who is chanting. An increase in the speed of chanting increases the speed of mind, heartbeat and respiration. The beat cycle of the mantras affects the emotions.
A fast speed sometimes creates a continuous vibration and when it is done in groups it creates a good effect, because the mind works in synchronization with the beat cycle and has no time to fantasize. Fast chanting of mantras exhausts the mind, heart and breath and relaxation comes after the chanting is over.
Slowing the beat cycle of mantras also creates the same continuous vibration, but it slows down the speed of mind, heart and breath while the chanting is going on. It induces a hypnagogic state, but it is good only when the chanting of mantras is done individually. A medium-speed beat cycle is good for group and individual chanting of mantras. It does not disturb the heartbeat or breathing pattern and makes the mind more awake, alert and conscious.
The place from which the sound emanates influences its' tonal quality. Deep tones are produced by the vocal chords in conjunction with the abdominal region, middletones in conjunction with the chest, heart and throat regions and high-pitched tones in conjunction with the upper region of the body. Indian classical music uses all three regions in a gradual order, but the middle region is used most and produces a greater emotional impact on the listeners.
Following are some of the main mantras used in Mantra Yoga (they play in loop):
Ganesha Mantra Text
KAPITTHYA JAMBOO PHALCHARU BHAKSHANAM
NAMAMI VIGHNESHWAR PADPANKAJAM
Elephant-faced, worshipped by the existing beings, of all living beings,
tasting the elephant apple (kaith) and jambolana (jamun),
the son of Uma, destroyer of grief,
I bow to the lotus feet of Ganesha who is Lord of all.
Saraswati Mantra Text
AING SARASWATYE NAMAH
Aing is the bij-akshar (seed syllable or condensed form of the larger mantra) of Saraswati.
If repeated 500.000 times, one can see Saraswati and will become enlightened.
50.000 Repetitions should be accompagnied by Homa.
Durga Mantra Text
AING HRING KLEENG
This is the most popular mantra of the divine Mother Durga.
This mantra should be repeated 500.000 times.
The fire worship should be performed with 50.000 ahutis of the same mantra.
Kali Mantra Text
KRING KALIKAYE NAMAH
Kring is the bij-akshar of the divine Mother Kali.
The number of japa is prescribed at 500.000.
Homa with 50.000 ahutis should be performed afterward.
Mahalakshmi Mantra Text
SHRING HRING KLEENG
Shring is the Lakshmi bija. The prescribed number for japa is 100.000.
10.000 ahutis of ghee and samigri bring Mother lakshmi's blessings in the form of peace, prosperity and harmony.
Brahma Gayatri Mantra Text
AUM PARMESHWARAYE VIDMAHE
TAN NO BRAHMA PRACHODAYAT
The Brahma Gayatri mantra is used to increase productivity.
Hanuman Gayatri Mantra Text
TAN NO HANUMAN PRACHODAYAT
The Hanuman Gayatri mantra is used for increasing love in performing duties and selfless service.
Krishna Gayatri Mantra Text
TAN NO KRISHNAH PRACHODAYAT
The Krishna Gayatri mantra is used for succes in job and an increase in activity.
Ram Gayatri Mantra Text
SITA BALABHAYE DHI-MAHI
TAN NO RAMAH PRACHODAYAT
The Ram Gayatri mantra is used for security and increase in name and status.