Yes, that’s a giant hammer.
The Austin Symphony is performing Mahler’s Sixth Symphony in two weeks. It’s a very intense, emotional (and very long) work. But even if you don’t listen to all of this brilliant performance, check out the giant frickin’ hammer in the last movement. The first blow comes at 1:05:50, before the brass chorale, and again at 1:10:35 before the second statement of the chorale.
This is a very large orchestra, with 4 harps, 6 trumpets, 8 horns, every string player in town, pretty much every percussion instrument imaginable, and while it’s relatively common for a composer to call for an anvil sound (usually replicated by beating on a brake drum), it’s the only Mahler symphony to include a giant hammer. It’s not entirely clear why Mahler wrote for the hammer, but I think he was after a sound that you felt in your chest but don’t necessarily hear, and some have called them “hammer blows of fate.” Either way, it’s pretty intense.
The sound of the hammer, which features in the last movement, was stipulated by Mahler to be “brief and mighty, but dull in resonance and with a non-metallic character (like the fall of an axe).” The sound achieved in the premiere did not quite carry far enough from the stage, and indeed the problem of achieving the proper volume while still remaining dull in resonance remains a challenge to the modern orchestra. Various methods of producing the sound have involved a wooden mallet striking a wooden surface, a sledgehammer striking a wooden box, or a particularly large bass drum, or sometimes simultaneous use of more than one of these methods.
And, if you’ve gotten far enough into the video to hear the remarkable trumpet playing by Reinhold Friedrich, those guys are playing rotary trumpets, different from the piston trumpets you are probably familiar with. The rotary valve (no, not Mazda) is like the valve on the horn, and the instrument generally has a warmer, less piercing tone than a piston trumpet. They are used primarily in Germany, Austria and eastern Europe, but they have become more popular in recent years in the US and other countries for performance of works by Beethoven, Brahms, Mozart, Bruckner, and others.