So what did they listen to, exactly? It couldn't be the same as listening to popular or classical music. Nope. It surely wasn't music, but there was often a "beat".
Radio and radar receivers aboard SAC bombers produced audio signals which EWO's and DSO's depended upon to identify the radar environment around their planes. In fact a discerning ear could readily identify the types of radars out there, what modes of operation they used, and whether or not they presented an imminent danger to the airplane.
The pulse repetition frequencies of radars are a definite indicator of type. Long range search radars typically transmit fewer pulses per second than short range anti-aircraft (AAA) gun tracking or missile threat radars. The audio characteristics important to flight crewmen are a key indicator of whether they are being "painted" by enemy radars of different kinds. Low pitch sounds were usually less of a threat than higher pitch sounds.
The scan rate, how often the radar beam sweeps the sky, also provides an audio cue for the trained operator. Low scan rates are again typical of high powered long range search radars, with scan rates of one or two revolutions per minute. Height-finder radars sounded very different from horizon scanning search types. AAA and missile radars scanned very quickly and in quite different patterns too.
Some radars changed both scan rates and pulse repetition rates in different operating modes. The change of either was readily detectable by audio signal switching. It was a matter of crew survival to be able to know what was going on around the plane. Timely and judicious application of countermeasures depended upon awareness of the radar environment out there.
Radar-equipped interceptor and fighter aircraft also produced distinctive audio signals of interest to bomber crews. Whether the fighter radar was in the search or tracking modes was of constant interest to bomber folks. Their characteristic raster scan or spiral search patterns produced distinctly different sounds.
Knowing what the sounds of the world out there mean can be the difference between life and death for bomber crews. And that goes for fighter crews too. For it was that very training and experience of years in bombers that paid dividends to this writer during aerial reconnaissance flights in Vietnam.
On one mission up over North Vietnam in the late 1960's, I detected the tell-tale audio signals of a ground-to-air missile site switching modes. We were the subject of the missile site's attention and about to have a missile launched at us. The sudden switch of audio signal pitch indicated that our RF-4 crewwas in imminent danger.
We immediately initiated evasive maneuvers, just in time to visually detect a flame-trailing telephone-pole-sized SA-2 headed right for us. That extra few seconds of audio warning gave us the chance to avoid disaster. I sincerely believe we wouldn't be here now without the benefit of all that audio training.