"in the standard repertoire", yes.
However, not the actual longest, which if we stick to the title "symphony" would have to go to Kaikhosru Sorabji's "Jami" Symphony (Symphony no. 3), which clocks in at around 4 hours, 30 minutes.
This is actually a symphony, not a filmscore, not some extended concert work, nor a piece of experimental theatre music performed in the forest overnight...
Kaikhosru Shapurji Sorabji
you will find this work listed on the McGill university website above, and it is clearly listed as a symphony. It is in 4 movements.
The timing I found has the 1st movement clocking in at 1 hour 34 minutes (the entire length of the Mahler symphony), the second movement nearing 20 minutes, the 3rd movement alone at 2 hours, and the finale just shy of 45 minutes.
Now, for all I know, the music is crap.. but then, Sorabji IS a known composer. His works have been recorded numerous times, as well as published.
He is also known for writing LOOOOOOOOONG pieces of music (his "Opus Clavicembalisticum" lasts just under 4 hours, and HAS been recorded a number of times (takes up 5 CDs).
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Now, all this brings up is, SO WHAT!!!???
Who really honestly CARES if composer-X wrote the longest / shortest / loudest / softest /biggest / smallest / weirdest / most boring /whatever-est symphony?
I think it is considerably more important that you understand what makes "Victory at Sea" NOT a symphony, or the "Lord of the Rings Symphony" again, NOT a symphony.
What makes a symphony a symphony? Putting the name on the score doesn't cut the mustard.
There are many composers who have written symphonies that are just NOT the cohesive, integrated works that a symphony should be. (
For purposes of this discussion, we will ignore symphonies from the early period, since many of those WERE "a bunch of separate movements strung together and simply called symphony")
What is the cohesive factor that makes Schostakowitch's 14th symphony, with its odd orchestration, and stranger-still form, BE a symphony?
Why are single movement works like Sibelius' 7th symphony, Samuel Barber's 1st Symphony, or Roy Harris' Symphony no.3, still "symphonies"?
These are some of the most exciting music, with some of the most intriguing formal innovations you can study during your life as a composer. To fully understand HOW these composers came to synthesize the symphonic stucture into a tightly constructed single movement is mind boggling and inspirational.
/professor mode off