Even my Quiet One is so quiet I can't even hear it running unless I literally shut off everything else in my house. Even though I have an open stand and even when I'm working in the sump. My HVAC is louder. 
Most pumps should be very quiet if installed correctly. "Noisy" means something is broken or mis-installed. But some like the Sicce's and Quiet One's are extremely quiet. I don't know how much more quiet one could get.
It would be interesting to see someone bring over a comparable DC pump and a sound meter.

Most pumps should be very quiet if installed correctly. "Noisy" means something is broken or mis-installed. But some like the Sicce's and Quiet One's are extremely quiet. I don't know how much more quiet one could get.
It would be interesting to see someone bring over a comparable DC pump and a sound meter.

but with that comes cost that I cannot justify.

