  This article proposes a characterisation of the double-reed in quasi-static
regimes. The non-linear relation between the pressure drop $\Delta p$ in the
double-reed and the volume flow crossing it $q$ is measured for slow variations
of these variables. The volume flow is determined from the pressure drop in a
diaphragm replacing the instrument's bore. Measurements are compared to other
experimental results on reed instrument exciters and to physical models,
revealing that clarinet, oboe and bassoon quasi-static behavior relies on
similar working principles. Differences in the experimental results are
interpreted in terms of pressure recovery due to the conical diffuser role of
the downstream part of double-reed mouthpieces (the staple).
