low backlash planetary gearbox

Perhaps the most obvious is to improve precision, which is a function of manufacturing and assembly tolerances, gear tooth surface finish, and the center distance of the tooth mesh. Sound can be suffering from gear and housing components as well as lubricants. In general, expect to pay more for quieter, smoother gears.
Don't make the mistake of over-specifying the motor. Remember, the insight pinion on the low backlash planetary gearbox 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 absorb the developed torque. Obviously, using a more powerful motor than necessary will require a bigger and more costly gearhead.
Consider current limiting to safely impose limits on gearbox size. With servomotors, output torque is definitely a linear function of current. So besides protecting the gearbox, current limiting also shields the engine and drive by clipping peak torque, which can be anywhere from 2.5 to 3.5 times continuous torque.

In each planetary stage, five gears are at the same time in mesh. Although it's impossible to totally eliminate noise from such an assembly, there are several ways to reduce it.

As an ancillary benefit, the geometry of planetaries matches the form of electric motors. Thus the gearhead could be close in diameter to the servomotor, with the output shaft in-line.
Highly rigid (servo grade) gearheads are usually more expensive than lighter duty types. However, for fast acceleration and deceleration, a servo-grade gearhead could be the only wise choice. In such applications, the gearhead could be viewed as a mechanical springtime. The torsional deflection resulting from the spring action adds to backlash, compounding the effects of free shaft movement.
Servo-grade gearheads incorporate a number of construction features to reduce 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 have a tendency to be the costliest of planetaries.
The type of bearings supporting the output shaft depends on the strain. High radial or axial loads generally necessitate rolling element bearings. Small planetaries could get by with low-price sleeve bearings or various other economical types with fairly low axial and radial load capacity. For bigger and servo-grade gearheads, durable result shaft bearings are often required.
Like most gears, planetaries make sound. And the quicker they operate, the louder they obtain.

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