I'm recently bought
Aqueon QuietFlow™ Power Filter and it a lot quieter than AC70 but the AC70 mechanical filter part work better than Aqueon so it's a bit trade off for noises and performances. Anyway, he will get used with the noises for first few days, after that he won't even notice the filter running while he trying to sleep
I have an Aqueon quiet flow buzzing away making more noise than a AC70, a cheap tetra air pump, a large old 4 outlet airpump, and a 600gph pump feeding a gutted Emperor 400 combined! My experience differs from everyone whose posted so far. I find the Aquaclears to be far and away the best HOB filters.
Emperor is the loudest atleast eventually in my experience with all its moving parts and needless over engineered "features". I tore the bio wheels off to stop it from squealing.
The Quietflow was a huge let down. It's the newest of the bunch by a long shot and is super loud, doesn't allow easy use of diy media (uses proprietary replaceable filter inserts), and it had some LED on it to remind me that I am supossed to buy more of their products monthly....which I do not.
The Aquaclear in my experience is by far the most quiet, are very reliable, and they simply use a big old open tub for their filter cart that you can fill with scrubbies or whatever you want!
Your mileage may very but I think you have a get setup in terms of filters.