Machine noise can often be a problem and the best way to deal with this is to cover the unit with a soundproof enclosure. The enclosure itself needs to be fabricated from heavy materials to block the noise and an absorbent lining will improve things further by reducing the amount of reverberation build up inside the box. Structural contact between the enclosure and the machine must be avoided otherwise the vibrations will be transmitted to the enclosure walls and re-radiated outside. If the noise is structure-borne then vibration isolators can help but these will generally only reduce the low frequency components below around 100Hz from transmitting into the building.
Materials such as our Visco-elastic Damping Membrane VL-65 can be applied to vibrating surfaces to reduce the overall sound output.
The following diagrams show the design and effectiveness of various machine enclosures: