Good observation! Traffic noise is the bane of modern civilization. Increases in social services, i.e. government financial assistance to the poor, unemployed, and disabled surely played a role as well. Don
Here in the green centre line is an Australian Aboriginal didgeridoo, a long instrument usually resting on the ground, and blown with continual breaths - needing much breath control. An eerie sound sometimes, and very moving and evocative of its history. This is part of an Australian-Asia link 1971, crafts and performers set.
Not an music-instrument per se,but a useful music-tool: the tuning-fork. stamp issued July 12th,1962;
Post Horn of the Deutsche Reichspost,commemorating the 100th anniversary of the Post Museum,founded by Heinrich von Stephan. stamp issued Aug.18th,1972;
Here's a stamp from Moldova, a country situated between Romania and the Ukraine. The instrument pictured is a cimbalom. The cimbalom is a common instrument in eastern Europe and a traditional instrument in klezmer music. The folk music of Hungary uses quite a bit of cimbalom. https://i.pinimg.com/originals/f1/32/73/f132736402a75d3b359644fb47f2ea50.jpg
Don, the instrument is played with a couple of a "hammers" somewhat similar, but distinctly different from the xylophone. I have a picture of one type here. http://www.alexanderfedoriouk.com/Cimbalom-Sticks_Horizontal_12.gif