Mechanical keyboards can be loud and noisy, as they use mechanical switches which produce an audible click sound when the key is pressed. The level of noise can vary depending on the type of switch used in the keyboard, as well as the user's typing habits. For example, Cherry MX Blue switches are known to be louder and more clicky than Cherry MX Brown switches, which are considered to be quieter.
Some users might find the sound of a mechanical keyboard to be satisfying and prefer it over the quietness of a rubber dome keyboard, while others might find it to be too loud and distracting. Some mechanical keyboard manufacturers have introduced switches that are designed to be quieter, such as Cherry MX Silent or Cherry MX Silent Red, but they are not as common as the standard switches and may have a higher cost.
It's worth noting that the keycap material, thickness and the stabilizer used in the keyboard also can affect the noise level. A thicker keycap and a good quality stabilizer can help to reduce the noise level.
If the noise level is a concern for you, it's recommended to try out different types of mechanical switches before purchasing a keyboard, or to look for a keyboard with quieter switches, such as Cherry MX Silent or Cherry MX Silent Red. Additionally, you can use o-rings and dampeners to reduce the noise level of the keycap, but it will not completely eliminate it.