Watercooling Swiftech h20-220 pump noise

I have been searching for a definite answer for this.

I recently installed the h20-220 compact system and I am satisfied with my temperatures but I am not satisfied with the pump noise.

Is there a way to safely control the speed of the apogee drive pump? Like a fan controller with the proper connection and wattage/voltage tolerance. I have read that the pump needs a certain amount of watts that is much higher than a fan.

I am asking this because I am a little disappointed with how loud the apogee drive pump is. Vibration is not the issue. It is actual pump noise. It makes two different noises and switches randomly between each one. One is a low hum the other is a higher pitched hum. Both noises are low but I thought it would make one constant noise. Is this normal? I have verified that the system is fully bled and pump is pumping fine.

How do I know if the noise of my pump is normal or if it should be quieter and there is something wrong? Are there any sound recordings of the pump that I could compare to?

Thanks for your help.