Music Thing looks at the important question of
why ice cream vans sound the way they do, with a subtext of finding ways of emulating that sound in a studio:
" Early models consisted of a hand tuned Swiss musical movement (like a music box) fitted with a magnetic pick up and the amplifiers used radio-type valves. In 1958 reliable transistors came on to the market and efficient amplifiers were built to work directly of the vehicle's battery."
British vans traditionally use 'Grampian Horn' loudspeakers (which cost about £60), pointed down at the road to disperse the sound.