Replying to your post very late, but nevertheless, here is an answer for you.
This is perhaps the one and only video clip of a JT4-powered DC-8 (series -20) aircraft, where you can at least hear a bit of the engine sound. Unfortunately, when it flies by, the engines are not revving that high, so it "appears" to sound quiet. But wait after the fly-by, and you can hear the muffled boom of the exhaust as the jet completes its wave and begins to climb.
May the wind be always at your back . . . except during takeoff & landing.