I just took UA
today and I agree! We were on a 737-500. During the landing roll, with the ground spoilers still deployed, the flaps began to retract. From seat 17A, I was able to see the long green-colored bar beneath the spoilers rotate (noisily) to retract the flaps. It was very loud without the spoliers stowed. Howver, I also flew CO
737-800 and 900 craft over the weekend, and I didn't find them to be any less noisy.