Alot may have to depend on when you home or ductwork was installed. When SEER 10 was about the best you can do ductwork installed was not really a big factor on cooling for residential homes. As AC units got better and the SEERs went up, one trick was to blow a larger volume of air slower over the coils so the outlet of the air handlers were increased. Also ductwork was sized up. If at one time an 8" duct was the norm, now it would be a 10" or larger. Smaller ductwork usually will result in higher air flow.
Just about all blowers motors are multi-speed. It is either by changing a switch option or just connecting the power to a different connector on the motor. If you have the manual it may have a set of instructions to change the fan speed. When you get to the very high efficient AC units (SEER 18 or higher) the blower motor will run at different speeds (variable) depending on outdoor/indoor air temp, humidity levels and the set point of the thermostat.
Since you have a furnace/blower set up, usually in heat mode the fan blows slower and when it is switched to cooling the fan speed is increased. This is also true with an AC air handler with an electric heating element for residential heating. Just to give it a try move your thermostat to heat and turn it on and listen if the noise is reduced or at the thermostat turn on the "fan". This will usually run the fan at the slower heating speed. The company or tech that installed your system can easily change it for you. It is really all part of the install.