  In the last years, space missions such as COROT, Kepler or MOST have provided
very accurate photometric observational data. In the particular case of
$\delta$ Scuti stars, the observed frequency spectra have hundreds (if not
thousands) of modes and a clear amplitude distribution. In this work we present
new techniques for modelling these observations and the results obtained. We
searched for regular patterns in the observational data, which yields something
resembling the large separation. This allows to reduce the possible positions
of the star in the HR diagram, yielding a value of the mean density with an
accuracy never reached before for isolated stars of this type. Finally, we
answer whether a $\delta$ Scuti star is stable despite all of the observed
frequencies are simultaneously excited.
