Abstract: To produce a three dimensional sound, an original sound recording is duplicated and the original of its duplicate are then recorded with a time delay in the range of 25 ms to 990 ms, preferably 100 to 500 ms. The resulting first echo recording is duplicated to produce a second echo recording and these are recorded with another time delay, preferably less than the first but within the aforementioned range to yield a fifth tape which has a so-called third echo imparting to the sound a three-dimensionality which cannot be achieved by conventional reverberation and echo methods.