crystalline, crystal clear, limpid, lucid, pellucid, transparent -- (transmitting light; able to be seen through with clarity; "the cold crystalline water of melted snow"; "crystal clear skies"; "could see the sand on the bottom of the limpid pool"; "lucid air"; "a pellucid brook"; "transparent crystal")
diaphanous, filmy, gauzy, gauze-like, gossamer, see-through, sheer, transparent, vaporous, vapourous, cobwebby -- (so thin as to transmit light; "a hat with a diaphanous veil"; "filmy wings of a moth"; "gauzy clouds of dandelion down"; "gossamer cobwebs"; "sheer silk stockings"; "transparent chiffon"; "vaporous silks")
(Sound)
