Having been present at performances of Sorabji's Symphonic Nocturne (130mins); Piano Symphony 6 (5 hours), Sequentia Cyclica (7,5 hours) and Organ Symphony 2 (8,5 hours), I can very much say: not so. Even the longest single stretch in these works (the 2nd movement from the Organ Symphony at 4,5 hours of previously unknown music) went by without a single moment of dullness or fatigue (and then some 3 hours of music had still to come!). Of course, if the music doesn't work for you, it would be torture, but that is so for all music.
Indeed. The listener does need "stamina" but any listener who cares about what he/she listens to and gets as much from the listening experience as possible can be preseumed to possess the requisite stamina, but that stamina is purely mental, not physical as is required of the performers. Also, as you note, that listener stamina might in any case seem to be less than one might assume because of the effect (when it manifests itself) that real time is overriden by perceived time; I well recall John Ogdon "warming up" for
Opus Clavicembalisticum recording sessions wih Busoni's Fantasia Contrappuntistica and thinking that the piece was probably a little over a quarter of an hour whereas in fact it was about twice that.
I also recall the Dutch pianist Reinier van Houdt saying, after having given the world première of Sorabji's Piano Symphony No. 4 (which is almost as long as the same composer's 6th and final piano symphony), that the music itself somehow seemed to energise him during his performance; it is curious but John Ogdon said almost exactly the same after
his performance in 1988 of
Opus Clavicembalisticum in London; indeed the performance itself had clearly gained strength and energy as it progress and John must have realised this because he said that he'd like nothing more than to go out onto the stage and play it again - and he'd have done it, too, had no one restrained him! So it's not just a question of how much stamina of all kinds is required; it's also a matter of where and how it might be sourced and how much of it can be sourced thereby.
I think, therefore, that what needs to be taken into account when considering this phenomenon is not only how much the music takes out of its performers and listeners but also how much it gives them back.
How anyone can survive the whole of Einstein on the Beach is beyond me
Indeed; one can pehaps understnd the prescience in Churchill's "we shall fight them on the beaches".
e=mc
2 - where e = enervation/ennui, m = minimalism and c = c**p; never once is a fillip provided and the ears glaze over. Had the work included some kind of Knut character trying vainly to push back the sound waves on that beach, it might have been just that little bit more bearable.
Someone who did survive that work in its entirety once said that he had to rush to cleanse his ears and mind with a good dose of Elliott Carter; I can imagine that listening to his Concerto for Orchestra after that would do the trick very effectively...
Best,
Alistair