The Spanish voiced obstruents /b d g/ are traditionally described as having each two allophones: stop and fricative (approximant) in complementary distribution. Several researchers have noted that some Central American and Highland Colombian varieties deviate from the general allophonic distribution in showing a preference for stop realizations in all contexts, except for the intervocalic position. In this paper we report on a large-scale acoustic investigation of /b d g/ in postconsonantal (after a liquid, sibilant or glide) and postvocalic (after /a/) contexts in Costa Rica Spanish, establishing a comparison with the variety of Madrid, Spain, which we take as representative of a variety with the general pattern of allophony. Our study, based on a continuous measurement of intensity, confirms previous descriptions in that Costa Rica Spanish does indeed show a different pattern of allophony from that found in the Madrid variety. The analysis shows that in Costa Rica Spanish postconsonantal realizations of /b/ and /d/ are very different from postvocalic ones, with a clear separation in the degree of constriction between these two contexts. In Madrid, on the other hand, we find a continuum of constriction degrees, depending on the nature of the specific preceding segment, and without a clear separation between postvocalic and postconsonantal realizations. The question that naturally arises is that of the historical connection between these two patterns of allophony, for which we offer some speculation, based in historical parallels and comparison with other varieties.