Once this stage has been completed, work can start on the production of final tools and equipment for the manufacture of all parts. Attention is now focused on second-level suppliers and production methods: purchasing, quality of suppliers and production methods, play an important role in this stage.

At the proposed production plant an initial review of the manufacturing process for the loudspeaker being developed is carried out. This allows control plans and production flow process to be optimised by clearly identifying process variables.

On recieving final of tool parts and equipment, the supplier quality department and the laboratory carry out a key role once again. While the laboratory undertakes manual assembly of all loudspeakers required for the audio system in order to verify their compliance with project specifications, the quality department "certifies" the quality of supplies. This is carried out using the pre-series products in accordance with similar criteria as to that required by the end customer. This process continues even after mass production start up and is based on a continuous performance-monitoring plan.