The search for new thermoelectric (TE) oxides has been driven by the discovery of high figures of merit ZT in complex layered cobaltates such as Na(x)CoO2 or Ca3Co4O9. Relying on abundant and non-toxic transition metal elements, these materials can be an alternative to currently used TEs such as PbTe or Bi2Te3. Complex relaxor ferroelectric oxides crystallizing in the tetragonal tungsten bronze (TTB) structure are a new class of TEs, of which the prototypical example, Sr(x)Ba(1-x)Nb2O6 (SBN), shows promising ZT values upon reduction, ie. as Sr(x)Ba(1-x)Nb2O6-delta (SBN-delta). We propose to use V2 for a comparative study of the phonon and soft mode behavior of a related TTB, Ca(x)Ba(1-x)Nb2O6-delta (CBN-delta), with SBN-delta, around their para-to-ferroelectric transition temperatures, as it was recently shown for stoichiometric SBN that the transition is driven by diffuse scattering related to polar nanoregions rather than by a softening TA phonon. We request 12 days of beamtime.