<p>The distribution of lexical stress is sensitive to the weight of rhythmic units such that heavier units more strongly attract stress. This paper addresses the question: what is the rhythmic unit relevant for weight computation? The traditional approach links weight to the <em>syllable</em>: weight is computed over the syllable rime (review in Blevins 1995), possibly with limited onset-sensitivity (Kelly 2004, Gordon 2005, Ryan 2013). I present experimental data which challenge this view, and support a recently proposed non-syllable-based alternative according to which weight is computed over the total vowel-to-vowel <em>interval</em> (Steriade 2012). Using a nonce word production paradigm, I test how likely participants are to stress the initial vs. final vowel in bi-vocalic sequences, manipulating the consonantal interlude separating the two vowels between a single C (e.g. <em>aka</em>) and CC cluster (<em>akra</em>). Initial stress is more likely with CC than C -- medial consonants contribute weight to pull stress to the initial vowel, CC contributing more weight than C. This is incompatible with syllable constituency which parses C/CC in the onset of the final syllable (<em>a.ka</em>, <em>a.kra</em>), and supportive of interval constituency which parses C/CC in the initial interval (<em>ak*a</em>, <em>akr*a</em>).</p>