Voyager 1 detects faint, persistent hum

[BIAD]

The faster one travels through the plasma medium, the higher pitched the hum should become, theoretically, just as
a harder rain has a different pitch on a tin roof from a softer, gentler rain...

So theoretically, the craft could speed up and slow down, thus creating a tune!
Who knows, years from now a rendition of 'Edelweiss'  or 'Heart & Soul' could come wafting back to Earth!