TAPC 4040 hifi centre needed to enter the market quickly to correspond to the products of competitors entered by their competitors. TAPC4040 was a very progressive device. Unlike his competitors, it had a so-called back amplifier which produced reflected sounds, and provided in addition to normal stereo sound a third dimension for listening. This was close to modern 3D-listening and unique at the time. The picture shows a draft of Vaajakallio's hifi centre, year 1975.