A lot of the noise is from the SRAM chain. I use and recommend using a KMC chain. Near silent.
My SRAM drive train is actually fairly quiet. Not as quiet as my Ultegra SL, but still. I use a 1090R chain.
I'm using a KMC chain. On a scale of 0-10, I'd rate my Ultegra a 1 and my Rival maybe a 2. I agree that it is pretty quiet. I don't notice the difference unless I'm going really slow like when I'm climbing a hill. It's certainly not noisy enough to stop me from preferring it over Ultegra.