Fuel generators, especially powerful ones, can be very noisy. Manufacturers are aware of this and try to reduce noise levels, but most equipment still produces more noise than expected.
Depending on how the generator will be used, one or more silencers may be needed.
Usually a special foam insert is used which is cut into the generator casing and attenuates the noise to the desired decibel level and is suitable for use in high traffic areas such as homes and hospitals.
This is only necessary when low noise levels are required by law and the generator must meet these requirements, increasing the final cost of the equipment. This competence is not necessary for e.g. engineering work.
However, you should always choose a product that meets the relevant safety standards.
If you want to use the generator in a public place, such as a campsite, make sure there are no noise restrictions or you can buy the best quite generator that are completely silent and you can enjoy camping without noise. This will help you to know the installation requirements for the various components.