This paper follows up on some of the phonetic assumptions underlying earlier discussions in the phonological literature of the vowel reduction in Brazilian Portuguese such as Crosswhite (2004) and Flemming (2004), among others. We investigated various reflexes of prosodic prominence across four positions: tonic, pretonic, posttonic, and word-final. The height of the low vowel /a/ in these contexts was also determined. We found that while duration readily distinguished among the first three positions (tonic > pretonic > posttonic), it failed to differentiate posttonic from final. Intensity was a better discriminator across all four positions. We also documented a height harmony between pretonic mid vowels and the following tonic resulting in a seven-vowel pretonic inventory that parallels the tonic*. The implications of these findings for metrical prominence and dispersion accounts of vowel reduction are considered.15