I noticed a shot of a Yamaha grand piano at about the two-thirds mark, and a 1-second Yamaha logo shot in the intro. Also, a couple minutes before the end (for the first and only time that I noticed) the phrase "Yamaha Musician" was used. As far as promoting Nathan East's new album: less than five minutes. It seems to me, after actually watching the film, that there were a lot of (to quote stine_pine) "famous people gushing over him, over and over and over again" because each gush was associated with a stellar performer talking about a groundbreaking recording. There were lots of fast-paced cuts from scene-to-scene, but it seemed to me that that was because they had to make room for the overflowing amount of "gushing" coming from so many world-class artists. From Clapton to Earth Wind and Fire, to Lionel RIchie, to Daft Punk. Overall, this was a more than decent doc and nobody would "rush from the theater" lol.

Although music history fans will find some good stuff in this film, it becomes clear about 1/2 way through that this was funded by Yamaha to promote Yamaha instruments and to promote Nathan East's new album. In the first 10 minutes of the film it is well established that Nathan is an exceptional bass player with illustrious credentials and is an all around good guy. The majority of the rest of the film is primarily famous people gushing over him, over and over and over again so that you may be rushing for the exits before the film has ended. It is as much an infomercial as it is a documentary so beware.

Having said all that, there are some interesting nuggets in the film that may make it worth watching. If you are a fan of the history of rock, soul and other kinds of popular music, it may be worth a watch.