Perhaps the most obvious is to improve 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 affected by gear and housing components along with lubricants. In general, be prepared to pay more for quieter, smoother gears.
Don’t make the error of over-specifying the engine. Remember, the insight pinion on the planetary should be able deal with the motor’s result torque. What’s more, if you’re utilizing a multi-stage gearhead, the output stage must be strong enough to soak up the developed torque. Certainly, using a more powerful motor than required will require a bigger and more costly gearhead.
Consider current limiting to safely impose limits on gearbox size. With servomotors, result torque is a linear function of current. Therefore besides safeguarding the gearbox, current limiting also protects the engine and drive by clipping peak torque, which can be from 2.5 to 3.5 times continuous torque.
In each planetary stage, five gears are concurrently in mesh. Although it’s low backlash planetary gearbox impossible to totally eliminate noise from such 
an assembly, there are many ways to reduce it.
As an ancillary benefit, the geometry of planetaries fits the shape of electric motors. Therefore 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 fast acceleration and deceleration, a servo-grade gearhead could be the only wise choice. In this kind of applications, the gearhead may be viewed as a mechanical spring. The torsional deflection caused by the spring action increases backlash, compounding the effects of free shaft motion.
Servo-grade gearheads incorporate several construction features to reduce torsional stress and deflection. Among the more common are large diameter result shafts and beefed up support for satellite-equipment shafts. Stiff or “rigid” gearheads tend to be the most costly of planetaries.
The type of bearings supporting the output shaft depends upon the strain. High radial or axial loads generally necessitate rolling component bearings. Small planetaries could get by with low-cost sleeve bearings or additional economical types with relatively low axial and radial load ability. For larger and servo-grade gearheads, durable result shaft bearings are often required.
Like the majority of gears, planetaries make noise. And the quicker they run, the louder they obtain.
Low-backlash planetary gears are also obtainable in lower ratios. Although some types of gears are usually limited by about 50:1 or more, planetary gearheads lengthen from 3:1 (solitary stage) to 175:1 or more, depending on the number of stages.