  We perform a phenomenological comparison of the gravitational wave (GW)
spectrum expected from cosmic gauge string networks and superstring networks
comprised of multiple string types. We show how violations of scaling behavior
and the evolution of the number of relativistic degrees of freedom in the early
Universe affect the GW spectrum. We derive simple analytical expressions for
the GW spectrum from superstrings and gauge strings that are valid for all
frequencies relevant to pulsar timing arrays (PTAs) and laser interferometers.
We analyze the latest data from PTAs and show that superstring networks are
consistent with 32 nHz data from NANOGrav, but are excluded by 3.2 nHz data at
$3\sigma$ unless the string coupling $g_s<0.2$ or the strings evolve in only
about 10% of the volume of the higher-dimensional space. We also point out that
while gauge string networks are excluded by NANOGrav-15 data at $3\sigma$, they
are completely compatible with EPTA and PPTA data. Finally, we study
correlations between GW signals at PTAs and laser interferometers.
