The Ogham were said by some to have been formed by Sound and Form (as its parents). What better child of Sound and Form would there be but Music? It is a theory of Seán Ó Boyle that the Ogham represent the notes of a Celtic harp. My thoughts on Ogham go beyond this musical notation into realms of mantra and mantic states. In this, I do not think I am far from what Alain Danielou proposed when he said in Music and the Power of Sound:
"If we were able to reproduce the exact relations that constitute the natural names, we should recreate beings, things, and phenomena, because this is the very process of creation, explained by the Vedas and also indicated in Genesis, or in the Gospel of John when the 'creative Word' is spoken of. If, however, exact relations cannot be produced, approximate relations have a power, if not of creation, at least of evocation; sound 'works now in man's small magic, just as it first worked in the grand magical display of the World Creator.'
'The natural name of anything is the sound which is produced by the action of the moving forces which constitute it. He therefore, it is said, who mentally or vocally utters with creative force the natural name of anything brings into being the thing which bears that name.'
By the artificial construction of harmony we can go beyond the phenomenon of sound vibrations and perceive not sounds but immaterial relations through which can be expressed realities of a spiritual nature. We can thus lift the veil by which matter hides from its all true realities"
It is my experience that the Ogham can be used in such a way to produce altered states of consciousness and to open the doors to levels of reality. In a true language (such as Ogamic Irish) with nature words and names, there is a power to the harmony of sounds and the letters that give them birth/form. Everything has a music that is natural amd uniquely characteristic of it alone. The fundamental sounds determine the "Music of the Spheres." Each of these "spheres" can be represented by an Ogham, a note and a sound as well as a quality, an essence and a level of awareness.
For starters, the Ogham can and should be used as a means of transitioning between normal consciousness/reality and mystical/altered consciousness/reality in much the same way that Amergin does so in his poem that is sometimes known as the "Mystery." what Amergin did was to chant and to "become" a variety of mystical/magical symbols for states of being and reality in his poem of mastery over the cosmos. The Ogham characters each have at least three kenning-meanings associated with them from historical/traditional Druidic lists. These meanings can be used to form relationships to create transitions in states of being in a manner similar/parallel to the Tree of Life structure that is used in Cabala (after all, the Ogham are primordial sound/form; even trees in Druidic traditions).
The keys to doing all of this in a Druidic way are to thoroughly understand the traditions, tales and values/concepts associated with the Ogham symbols. This is really not much different from the analogous ways that other Magical systems work to establish esoteric hierarchies. Of course, some will say this is "smoke and mirrors" but to me those who say such things just display an ignorance or an avoidance of Celtic/Druidic ways when they don't put forth the work to actually understand such things. The Druidic Way is not for those who want easy/instant solutions.
Another parallel for this use of Ogham, tone and mantra/chant among Druids and the Filidh (their inheritors) is to be found in the use of Sanskrit letters, symbols, sounds and correspondences among the Brahmins and Yogis of India. In their system chant and mantra are the foundation of meditation and the pathways to enlightenment. Almost any Hindu or Vedic site on meditation or Yoga will give information similar to this found at Universal Mantra.
"The Yogis of the past, found that within our body and mind there is a vibrational activity, and this activity creates sounds. In their deep meditations they listened all this sounds and they cataloged them, they found fifty sounds, and now this sounds are the fifty letters of the Sanskrit alphabet. "
"In the tantric science of meditation these sounds are used to awaken higher stages of consciousness and they are combined together to create Mantras, special words based on this sounds."
Other sites for this sort of information can be found at: The River of Heaven which says:
"Hence the Yoga of sound is meant to take us back from our gross sounds to their idea content to the perception they represent and ultimately to the pure being behind that perception. It is not a process of merely saying sounds or thinking about words but tracing the origin of sound and meaning back to awareness itself by the power of meditation."
Awen and Imbas
"This information could be almost anything: events from a person's past life, a detailed history of who and what had happened to an object or even how and why the subject was bespelled or enchanted. The examples that I've seen seem to suggest to me that a spontaneous flow of information and/or poetic verse might accompany the first contact that occurred between the seer and the object. This verse would then be interpreted based upon the vast storehouse of Druidic knowledge that had been accumulated through many years of study, experiment, observation and experience. It is this interpreting of the extemporaneous recital of verse that involves the act of 'cracking open the nuts of wisdom'."
Damh the Bard tells us:
"During a Druid ritual, the Awen can be intoned as a single monotone note using three syllables "Ah-oo-en" (some Druid Orders intone the three letters I. A. U. in a similar way). The power held within the Awen mantra can be used in many ways - from initiating poetic inspiration, to drawing down the blessing of the God and Goddess or evoking a change in the atmosphere of a ritual circle. It is truly a sacred word. "
So it also was and still is among Druids regarding chant and mantra for meditation. Rudimentary use of this was first attempted by Iolo Morganwyg in the Barddic Mysteries and the Barddas, when he suggested that the Awen was represented by three rays/sounds/letters (which are I A U as given above). These are the "fifth", "primary" and "third" elements in the Ogham vowel group or Ailm Aicme. In any esoteric alphabet, the letters represent primary states and tones. In the Ogham, each grouping can have a relationship to the elements/qualities as well as the directions and parts of being. A study of some of the Irish tales has suggested associations for these to me that mesh in a web of interlinking meanings as well as tonic qualities.
One practice that could come out of this use/cross-referencing of Ogham to sound, is that an entire symphony of meaning could be arranged in a melody of notes while colors, lists and other associations (like blossoms and smells) would also allow a multileveled matrix/field-like approach to any esoteric or mundane situation/ritual using the Ogham lists (which were a part of every File and Druid's education). What this means is that there is a ready sourcebook in Druidic memory and tradition for spellwork, medicine, poetry and ritual to be found in the Ogham as music, symbol, talisman and knowledge indices.
I could go on at length about this (and have in books, seminars and classes on the subject) but these few short remarks should point to the wealth of knowledge that awaits one who seeks the knowledge that is to be found along the Druid Way (and especially through the use of Sound and Form and their child which is the Ogham).