Fan Voltage

Is there a way to simply adjust the voltage of a non variable-speed fan, and increase or decrease RPMs?

-YB

Yes, there's a device called a rheostat and you wire it up to the fan and there's a knob which controls the RPM and effects the CFM. Use the search button and you'll see diagrams to hook it up and information about it. I'm not too particularly knowledgeable with rheostats so someone who knows should help you.

Another alternative is you can run the fan at 7v with no controller.

you can put a resistor on the power line on the fan to slow it down.