Oh yeah, they are wicked loud. I had to wear ear muffs all the time with my 1515. It literally would pound my ears. The racket that tractor would make was deafening. Its not just from the exhaust either. Those tractors are loud internally. If you slow it to 1/2 throttle, you'll hear all kinds of clik'n and klack'n coming from inside. Here is a tip that I highly recommend:
I noticed my 2180 was getting really noisy, noiser than I had noticed before. I was kind of puzzled. Then I greased the spindles and the big center pulley zerk fittings really good. I turned the blades a revolution, greased it all over until I saw the grease oozing out. When I put the deck into action, what an amazing difference. All that noise was coming from my deck. I also had just put on a new pto belt, what a difference. My tractor seems quiet compared to before. Keep those decks well greased, not just for longevity but for your ears!