What sort of a noise filter you need to use to suppress the noise from mains electricity in your speakers? Explain.

A Notch filter.

Explanation:

This filter is a combination of high pass and low pass filter, the purpose of this filter is to suppress a frequency or a range of frequencies values, it is commonly designed for 50 or 60 Hz because that is the signal frequency of the mains electricity.

The high pass filter will suppress the frequencies below a defined frequency, and the low pass filter will suppress the frequencies above. then we have to sum both signals together and we will have the signal without the undesired frequency.