  The Coon amplitude is a one-parameter deformation of the Veneziano amplitude.
We explore the unitarity of the Coon amplitude through its partial wave
expansion using tools from $q$-calculus. Our analysis establishes manifest
positivity on the leading and sub-leading Regge trajectories in arbitrary
spacetime dimensions $D$, while revealing a violation of unitarity in a certain
region of $(q,D)$ parameter space starting at the sub-sub-leading Regge order.
A combination of numerical studies and analytic arguments allows us to argue
for the manifest positivity of the partial wave coefficients in fixed spin and
Regge asymptotics.
