From the Daion catalog: "The secret of the HH-555 tone and sustain lies in its center block.  It is made with 3 plies -- one dense layer of Maple sandwiched between 2 thick, softer layers of solid spruce.  Ten "sound grooves" are routed at either end of the block to add resonance, that elusive "singing" quality associated with some of the first semi-acoustic guitars.  Daion is the first to offer through-body stringing on a semi-acoustic to give that little extra sustain."

See the 1982 Daion catalog here

Link back to Daion index