The Syllable and the Foot : Summary - Speech Resource Pages

One of the main reasons, then, why languages have phonotactic
constraints is because their sequential arrangement is itself a cue to
the number of syllables in a word. When we produce an English
word like 'print' for example, we want to convey to the listener not
only that this word is composed of a certain number and type of
phonemes, but also that the word happens to be monosyllabic: and
the listeners' perception of how many syllables there are in a word
depends to a certain extent on the arrangement of phonemes in
sequence, as we saw from the example of /pʁ/ and /ʁp/ that has
just been given.
In order to explain why listeners hear e.g. /pʁi/ as one syllable, but
/ʁpi/ as two, we need to appeal to what has been called the
syllable's sonority profile.
Sonority Profile
Sonority is an acoustic-perceptual term that depends on the ratio of
energy in the low to the high part of the spectrum, but it is also
closely linked with the extent to which the vocal tract is constricted.
In general terms, open vowels like [a] have the highest sonority
because the vocal tract is open and a large amount of acoustic
energy radiates from the vocal tract. At the other extreme,
voiceless oral stops have least sonority because there is no acoustic
energy during the closure in which the vocal tract is constricted.
Languages prefer to build syllables with the most vowel-like sounds
nearer the middle, and the least vowel like sounds (=oral stops,
voiceless fricatives) near the edge(s). Syllable structured in this
way are said to conform to the sonority profile.
i.e. oral stops are less sonorous than fricatives which are less
sonorous than nasals etc.