Like usual very interesting comment from frogman confirmed by this reader comment under the video:
«There‘s another intersting interview (in German) with Christa where she says the following: Karl Böhm got it always right Karajan was always either too soft or too loud Bernstein was always either too slow or too fast But of the three, only Bernstein could communicate music with an unparalleled intensity. Christa, who will turn 93 in a week or so put that pretty well! »
It is common to think that the soloist always has the last word. This is not always the case at all. First of all, “Das Lied” is a symphonic poem; the orchestral writing is much more than simply accompaniment for the soloist. Whether the soloist (or listener) likes it or not, the maestro has the last word. Depending on the stature of the soloist, a conductor will be more or less deferential to the soloist’s wishes, whims and limitations. Moreover, this type of disagreement is common in the rehearsal process. In this case, the problem is not only one of differing musical visions. It is not that only she thinks that the music will be better served at a slower tempo. As wonderful as she is, she is clearly having difficulty keeping up with Bernstein’s tempo (her limitation). A smart conductor will recognize this and, when all else fails, will adjust his musical vision for the sake of the music. Otherwise, the end result will be the rhythmic mess that we hear in this example. It would be interesting to hear what the final outcome was. Bernstein was a smart conductor.