While spectroscopic methods in their ''standard'' application, such as fluorescence emission (Bong et al. 2000; Krishnakumar and London 2007; Wimley and White 2000) , circular dichroism (CD) (Chen and Wallace 1997; Koeppe and Andersen 1996) , and transmission infrared (IR) spectroscopy (Küsel et al. 2007) , produce qualitative information on the structure and localization of the peptide species, more advanced applications, such as oriented CD (Wu et al. 1990 ), attenuated total reflection (ATR) IR spectroscopy (Tamm and Tatulian 1997) , Förster resonance energy transfer (FRET) experiments (parallax method) (Chattopadhyay and London 1987; Chung et al. 1992) , solid state nuclear magnetic resonance (NMR) (Andronesi et al. 2004; Strandberg and Ulrich 2004) , and electron paramagnetic resonance (EPR) techniques (Dzikovski et al. 2004; Marsh 1996) , usually account for quantitative values in one dimension of the lipid bilayer without the need for complementary simulations or geometrical models (Naik and Krimm 1986a, b) . Some of these techniques require membrane states or parameters that are far from physiologically or biologically relevant. In addition, sample preparation for some applications, e.g., frozen state samples for EPR spectroscopy, are often prone to uncertainties and artifacts. Therefore, the sample preparation method itself has to be carefully evaluated, usually with significant effort.