The Beach Boys recorded "Wouldn't It Be Nice" as the opening track on their landmark album "Pet Sounds." It's my favorite Beach Boys song, but I never knew how insanely complex Brian Wilson's arrangement was: the recording includes two accordionists, two drummers, three bassists, three guitarists, four horn players, two pianists, and at least four singers. The main riff of the song is formed by the twin accordions (working together with a lovely walking bassline), though I would've been hard-pressed to tell you there was any accordion on that track until I watched the video below explaining how the song came together. What's most intense: those twenty musicians' parts were originally mixed down to a mono master. One track of audio to rule them all.
Watch this eight-minute video to learn details of the arrangement, along with audio from the original studio sessions:
My favorite line from the video: "It's a happy song about not having what you want."
It took 21 takes to get the backing track right, then a week to record the vocals. To understand the complexity of the vocal melodies alone, check out this audio bit isolating the vocals (you may wish to have a hanky ready, it's beautiful):
If you don't have "Pet Sounds," get the 40th anniversary edition, which includes remastered versions of most songs, plus various stereo mixes. For superfans, The "Pet Sounds" Sessions includes a bunch of the audio used in the video clips above. For more on the record, check out Wikipedia's extensive pages on "Pet Sounds" and "Wouldn't It Be Nice."