2217 --> 2
XP3 --> 4
FX5 --> 3
Medium size dual output airpump on a wooden floor --> 8 (for reference)
I have 2217 and FX5 right next to each other along with 2 airpumps (1x single ouput and 1x dual output) and for me to tell if my canisters are on I would have to physically touch the motor.
As for my XP3, I can hear it when I open my stand, but cant hear anything if I'm about 3 feet away.
BTW, I have a 30g right next to my bed (head actually). Right below it is an XP3 (inside a covered stand) and I can't hear anything. The only thing I hear are the bubbles from my sponge filter. Perhaps the XP3 makes some noise, but the bubbles completely overwhelms it.
No reason to go cheap on the tank's lungs, heart, and liver. The investment will pay over the next two decades ... that's how long those things will run for you. At least.
I have 2215 on my 46 and its very quiet
I have Fluval 405 on my 75... its quiet but the eheim is quieter.( i got it used on CL for 80 bucks)
If I were you, I would look for used 2217 and I run a power head sitting on sponge filter . If not enough filtration for what you need, I would add an aquoen 400gph power filter.. i just ordered one at petco.com for 34 bucks.. i heard they are quieter than marinelands. I have yet to find out.
Look on Craigslist for possibly good deals on used products.. just my 2c