Perhaps the most obvious is to increase precision, which really is a function of manufacturing and assembly tolerances, gear tooth surface finish, and the guts distance of the tooth mesh. Sound can be suffering from gear and housing components in addition to lubricants. In general, expect to spend more for quieter, smoother gears.
Don’t make the mistake of over-specifying the motor. Remember, the input pinion on the planetary must be able manage the motor’s result torque. Also, if you’re utilizing a multi-stage gearhead, the output stage must be strong enough to absorb the developed torque. Certainly, using a better motor than required will require a bigger and more expensive gearhead.
Consider current limiting to safely impose limitations on gearbox size. With servomotors, result torque is a linear function of current. Therefore besides safeguarding the gearbox, current limiting also shields the motor and drive by clipping peak torque, which may be anywhere from 2.5 to 3.5 times continuous torque.

In each planetary stage, five gears are simultaneously in mesh. Although you can’t really low backlash gearbox totally get rid of noise from such an assembly, there are several ways to reduce it.

As an ancillary benefit, the geometry of planetaries fits the form of electric motors. Thus the gearhead can be close in diameter to the servomotor, with the result shaft in-line.
Highly rigid (servo grade) gearheads are usually more costly than lighter duty types. However, for quick acceleration and deceleration, a servo-grade gearhead could be the only sensible choice. In this kind of applications, the gearhead may be seen as a mechanical springtime. The torsional deflection resulting from the spring action increases backlash, compounding the effects of free shaft movement.
Servo-grade gearheads incorporate a number of construction features to minimize torsional stress and deflection. Among the more common are large diameter output shafts and beefed up support for satellite-gear shafts. Stiff or “rigid” gearheads tend to be the costliest of planetaries.
The type of bearings supporting the output shaft depends upon the load. High radial or axial loads usually necessitate rolling element bearings. Small planetaries can often manage with low-cost sleeve bearings or various other economical types with fairly low axial and radial load ability. For larger and servo-grade gearheads, durable output shaft bearings are usually required.
Like the majority of gears, planetaries make sound. And the faster they run, the louder they get.

Low-backlash planetary gears are also obtainable in lower ratios. Although some types of gears are usually limited to about 50:1 or more, planetary gearheads extend from 3:1 (single stage) to 175:1 or even more, depending on the number of stages.