Volume and Expression Pedals
With pedals for musical keyboards for volume, it's possible to adjust the intensity of the signal sent from the musical keyboard to the stereo outputs, just like you can do through the knob or slider on the instrument's control panel, but with the advantage of being able to continue playing while making this adjustment.
The expression pedal operates slightly more complexly and sophisticatedly, as the variations it allows on the sound of a musical keyboard are more subtle and do not degrade the signal, but rather allow for nuances, also thanks to the fact that this pedal allows you to act only on the sounds and not on the effects, so as not to cause unpleasant interruptions in the performance. Another feature of this type of pedal is that some musical keyboards allow it to be programmed to act on certain controls or parameters.
Of course, in addition to the specific needs of the musician, in choosing which pedal to buy, it is important to know if your musical keyboard has an input for expression control (not all do), in which case the only choice is towards the volume pedal.
MusicalStore2005, the online music instrument store offers various brands and types of volume and expression pedals, both for musical keyboards and other instruments.
The working principle of volume pedals is different from the on/off operation of sustain pedals. Volume pedals are used to gradually vary the sound intensity. They are widely used with keyboards (but also with guitars) and allow you to continue playing without using a hand to operate the sound slider.
In any case, make sure that your keyboard is set up for connection with this type of pedal.