Are you using pressurized or DIY CO2? If it's pressurized, I'd just go ahead and buy a good diffuser and be done with it. DIY has trouble developing the pressure required to get some ceramic and glass diffusers working. If you are able to make or buy a reactor, that is a better option still, whether DIY or pressurized.
A lot of people inject CO2 into the inlets of their filters or powerheads. Depending on the setup this can be annoyingly loud or more or less silent.