  The COMPASS experiment at CERN is designed for light hadron spectroscopy with
emphasis on the detection of new states, in particular the search for exotic
states and glue-balls. After a short pilot run in 2004 (190 GeV/c negative pion
beam, lead target) showing significant production strength for an exotic
$J^{PC}=1^{-+}$ state at 1.66\,GeV/${\rm c^2}$, we have collected data with a
190 GeV/c negative charged hadron beam on a proton (liquid hydrogen) and
nuclear targets in 2008 and 2009. The spectrometer features good coverage by
electromagnetic calorimetry, and our data provide excellent opportunity for
simultaneous observation of new states in two different decay modes in the same
experiment. The diffractively produced $(3\pi)^{-}$ system for example can be
studied in both modes $\pi^{-}p \rightarrow \pi^{-}\pi^{+}\pi^{-}p$ and
$\pi^{-}~p \rightarrow \pi^{-}\pi^{0}\pi^{0}~p$. Charged and neutral mode rely
on completely different parts of the spectrometer. Observing a new state in
both modes provides important cross-check. First results of a preliminary PWA
performed on the 2008 data are presented.
