When people want to buy garbage disposers the price and noise are the two most important factors they keep in mind. Some models are relatively noise-free, but if they are not cared for, some of the internal parts may get damaged over time and start causing extra noise.
Usually the sound you hear is not the machine itself – it is from the vibration via your kitchen sink. More expensive units usually run smoother thanks to sound reducing elements in the mounting.
Waste King is one of the models that run really quiet whilst not being too expensive either. A win-win situation.
Models that cost more, are not only insulated well, they are also insulated on the inside. Some even have anti-vibration mounts and sink baffles which lessen the vibration (cause of the noise).
I am not going to go into the technical stuff. I am sure most of you aren’t interested in how it works, as long as it works!