Hi Deborah – I made the point about the seed (bija) mantras, from a yoga perspective. In tantric yoga they are short syllables with specific vibrations used for activating the first six chakras up from the base: Lam, Vam, Ram, Yam, Ham, Om. The crown chakra, sahasrara, has no associated sound. They are probably best chanted aloud in the first instance to get the vibration going, then can silently be internalised. They’re part of the wider kundalini awakening process but can be very helpfully used to focus on the properties of the individual chakras. (I use this system as part of my meditation practice.) Some of the seed mantras are also widely used as general mantras, for the purposes of stilling the mind within the wider system (s) of mantra meditation. Most obviously Om and also Ram(a). In my view, we are very fortunate to be able to merge yogic practices, based on centuries of in depth exploration, with our modern approaches to meditation based on insights from research and the ability to share findings from across the world. Love and light, Christine.