Noise in the signal path can adversely affect sound in many different ways.
It may be inaudible but it can distort the image and the accuracy of music reproduction.
Using a stepped attenuator to replace a common potentiometer can greatly reduce noise in signal path.
An attenuator can be configured as serial, shunt or ladder type. The serial-type is a series of resistors forming one voltage divider;
The signal pass through a number of these resistors before reaching the output. Depending on the type of resistors used, it doesn't
have great advantage over a common potentiometer.
In shunt-type, the signal only pass through two resistors; However, its input impedance varies
along with the switching position.
The design of the ladder-type adopts the advantages of both serial-type and shunt-type attenuators.
Like the shunt-type attenuator, audio signal only pass through two resistors in ladder-type.
Therefore it has lower noise floor than a serial-type. While the impedance in shunt-type is ever changing, ladder-type attenuator is more stable.
We use Vishay/Dale military grade resistors in this kit. It has extremely low noise and excellent high frequency characteristics.
Your sound system is only as good as the weakest link. Volume control is one of them.