April, 1969: John & Yoko.

Be honest, now: have you actually listened to the whole (or even any part) of The Wedding Album? If not, ye should, particularly side 1's opus "John & Yoko". Judging by comments on YouTube, this 22:44 gauntlet throwdown of a recording tends to elicit responses in individual listeners (occasionally participants) that run the gamut from extreme boredom to utter, eye-swivelling fury, via a brief detour down the (if you'll excuse the expression) cul-de-sac of sexual arousal.
Avant it may be, but not as much as it appears; the whole thing is actually an extended take on Stan Freberg's 1951 comedy single John And Marsha. John and Yoko never took themselves as seriously as others did (and, indeed, do).(Go HERE to hear.)
Now compare unt contrast. Above, the titular pair recording John's heartbeat in EMI's Studio 2, c. April 1969. The backdrop to John & Yoko is provided by the sound of their twin, errr, throbbers, sometimes galloping, occasionally almost faltering, over which John does Yoko, and Yoko does John, possibly literally (I hope that's an Apple he's eating).
Parts of it, no doubt, are silly/boring/etc. Yet there are also sections which, to use John's own words, can indeed seem almost "hair raising", if not downright harrowing in the light of the marriage's tragic demise.
Take the passage around 7:30, for instance, where a distraught Yoko cries John's name. Or, even more so, the section c. 12:30 - John appears to breathe his last as Yoko sounds like nothing so much as a flat-lining EKG machine. Palpable nonsense.
Of course, the effect is punctured shortly thereafter when they both get the giggles.
Nevertheless, if you've never heard it, here it is.
You're so very welcome.