Yeah, I know what you're driving at. Vaenska's 12:30 for the Adagietto sounds extreme. I think 9 minutes is OK, but it sounds ridiculous at 7:30. Consider what Mahler himself wrote in the score.
At the very beginning (of the Adagietto) Mahler wrote several things in the span of just three measures: "sehr langsam" (very slow), "molto rit." (slow down lots) and "a tempo (molto Adagio)" . . . . MOLTO ADAGIO! Nowhere does Mahler mark anything faster than "fliessand" (flowing) and - at rehearsal figure 2 - "fliessender" (more flowingly, I think).
Mahler AGAIN writes "molto adagio" at the "Tempo I" located after figure 3, followed by "zogernd" (hessitantly) at figure 4, and "noch langsamer" (even slower) after that! Clearly the man did not want this movement to rush.
Am I suggesting that Mahler, Mengelberg and Walter were all out of their minds? . . . YES, I AM. The proof is in the pudding: the Adagietto sounds stupid when it's played for less than 8 minutes. Personally, I don't care if it was 'love letter' to Alma, or to Goebbels, or to anyone else. Musically, it sounds best in the 9 to 11 minute range. Granted 12:30 is at the other extreme. That said, however . . .
. . . have you ever heard the Scherchen/Philadelphia Orchestra M5 from Tahra (which stayed in print for about 12 minutes)? . . . Scherchen does the Adagietto at 15:12 and it sounds fabulous! Of course, we're talkin' Philly here. Bruno Maderna - whom so many historical buffs hold up on such a high pedestal - did the Adagietto at 12:40. Bruno "freakin'" Maderna, folks.
No you don't. I'm driving at nothing.
Matters of tempo are relative, not absolute.
Modifications of speed as requested by Mahler are to be considered against the background of the basic tempo, which should be flowing. The programmatic issue concerning the love letters to Alma or Goebbles is not important, because it is something attached to the music
ex post facto. What matters is what is immanent to music. The rules of the game we are invited to play while listening music are dictated by the genre and by what the composer actually writes. Adagietto is an Italian word and, being Italian, I can assure you that it means "little adagio"; if Mahler had wanted it to be played like a big adagio, he would have headed it "Adagione"! :-) As it always happens in Mahler, he added contradictory indications to prevent interpreters from exaggerations (in the case of Adagietto, to make them avoid rushing things). As for the question of genre, the ABA form's Adagietto is a song without words and, given the tristanesque central section, a song concerned with love--for whom (Alma? Goebbles?) or for what (solitude in Nature's realm?) frankly it does not matter. What matters is that a song needs to be played
cantabile, what matters is that a love song is not a dirge/threnody.
And yet... as I wrote, matters of tempo are relative and an Adagietto sensitively shaped/phrased (usually stretching the central section) can be very nice even at the 11:34 of the Frankfurt/Inbal recording.
And yet... we do not have to forget that the Adagietto is part of a Symphony, it is its fourth movement, the first of the Symphony's third part. A sensitive conductor shapes it accordingly to his/her general vision of the entire Symphony. Considering it an introduction to the Rondo-Finale (Mahler wrote
attacca at the end of the Adagietto, while he even took a pause between the first two movements), the brisker the Finale, the brisker the Adagietto. Unless a conductor wants to balance the weight & duration of the first part of the Symphony by adding weight & duration to the third part, usually through relaxing the Adagietto (while I think this is a mistake, because I believe the first and third part have to be and kept asymmetrical, if it is done well I am perfectly happy with that).
I own almost every recording of Mahler's Fifth, included (alas) the infamous Scherchen's live one taped in Philadelphia. Let's tell the whole story about Scherchen & the Fifth. He recorded it in 1952 with the Vienna State Opera Orchestra (Westminster) and his tempi are:
I. 11:22/ II. 13:35/ III. 18:06/ IV. 9:15/ V. 15:19 = 67:39
On October 30, 1964 Scherchen conducted the Fifth with the Philadelphia Orchestra and his tempi were:
I. 13:03/ II. 13:46/ III. 5:42 (sic)/ IV. 15:12/ V. 10:29 = 58:14
He wrote to his daughter that he relaxed the Adagietto not to break the movement's world record for duration (which anyway, as far as I know, he still owns), but because the strings played wonderfully and could sustain the tempo he chose. But that tempo meant also that, in his perverse vision, with a Scherzo reduced to a bit less than 6 minutes and some cuts in the Finale too, the Adagietto needed to acquire weight and become the focal point of the third part to counterbalance the first part, which he executed without cuts (and very well, savagely enhancing the contrasts). With the pivotal Scherzo intact there would be no need to counterbalance anything, as his official, uncut recording of the Fifth clearly shows.
That said, Scherchen's disgraceful performance with the Philadelphia Orchestra is the musical equivalent of a rape. And I do not care if they played like gods and so on, because an inferior orchestra like the NHK Symphony of Tokio (
http://www.hmv.co.jp/en/artist_Mahler-1860-1911_000000000019272/item_Symphonies-Nos-4-5-Blomstedt-NHK-Symphony-Orchestra-Akiko-Nakajima-2001-1985-Stereo-2CD_4241320) playing Mahler's Fifth is better than a great orchestra like the Philadelphia Orchestra playing Scherchen's Symphony concocted with chunks of Mahler's Fifth.
Finally, Mahler and Walter were not out of their minds. It is just that up to 1950s there was a tradition, stemming from the composer himself, to play the Adagietto flowingly and it was perceived right and liked that way. When Bernstein played it as a dirge first for Serge Koussevitzky and then for JF Kennedy and when Visconti exploited it for Morte a Venezia (
Death in Venice), a new tradition began affirming itself; people who knew and experienced their Mahler in that new tradition, felt it right and liked it.
In the end I return to the beginning: I'm driving at nothing. I just enjoy great performances, even better if beautifully played, and where everything makes sense according to the conductor's vision. Tempi are relative to that vision. I like fresh, intriguing, thought provoking approaches, I care about tradition when it is something genuinely felt and expressed, I do not care about tradition when it is just
Schlamperei.