the synchronization block 412 gathers the data from the data sources blocks 402 404 406 408 410 and synchronizes the data using time stamps a relevance determination module block 414 determines the relevancy of the synchronized data for example the relevance determination module block 414 establishes that video of a car that passes a user and a street noise are related u2014 the noise comes from this car the synchronization is required for the semantic processing that was described in fig3 and for deriving rules for how and when to do earcons for example under noisy conditions earcons will be played louder for a user fig5 is a detailed operational block diagram for identification of the current earcon block 220 of fig2 according to embodiments of the invention a set of earcons block 500 is a module that stores a set of descriptions of available earcons for participating companies company related advertisements and other situational information the set of earcons block 500 also stores where such earcons are located and how they may be received the situational information about the various earcons is employed to identify what earcon to use in what situation some examples of earcon characteristics are provided in blocks 502 504 and 506 block 502 provides information about earcon time duration specifically short duration earcons that may be played.