So I Googled and found on inogolo.com a guide to brand pronunciations. Indeed, it says the phonetic and correct way to say Adidas is with the stress on the first syllable.
But in the notes section, inogolo does say that it is common to hear the brand pronounced ah-DEE-das in the United States.
We say, when in Rome ...
writeWimpyButton("/audio/Adidas_4728.mp3", "19", "19", "&playingColor=0086FF&arrowColor=FFFFFF&theBkgdColor=00008C&rollOverColor=EE0000&bufferAudio=2&display