Tod Spedding

As an avid meditator, I have been very interested in this phenomenon for many years, wondering about its source, interested in/drawn to what I perceive as an array of overlapping tones, as one might listen to the sounds of the rainforest, or the sounds emanating outside a bedroom window. I've wondered about it in much the same way as I wondered about the perception of "seeing" in darkness as a child -- really not uniformly dark, but pixilated. I wondered whether I was "hearing" the movement of blood through my ears, or the sound of my nervous system, akin to noticing the humming of an electrical appliance, like a refrigerator. I've never felt burdened or bothered by it, quite the contrary. It does remind me of the sensation that follows listening to loud music, a kind of muffled feeling/sensation. I still wonder whether any of us, children included, really hear silence, or whether there is always a background "noise," the result of our metabolism. I've looked for information on this, without success. Any insights?