The Deutsch-Norman model is a revised version of the Deutsch-Deutsch model. The original model focused on the importance of semantics. The revision included a second selection process to accommodate for the role of semantics in selective attention. Unlike Treisman's attenuation model, this model doesn't imply that unattended stimuli get processed into working memory. The unattended stimuli instead may pass through a secondary filter. This filter is what would then let only the important stimuli enter into working memory. This way only stimuli of important meaning would come into awareness when not paying attention.
This model is mentioned in the Cocktail Party Effect, check it out!