We aim to obtain phonon spectra on a series of new two-dimensional layered compounds, (CuxNi2-x)(CN)4 and the related parent material, Ni(CN)2. These materials show a range of thermal expansion behaviours: the magnitude of both the negative thermal expansion (NTE) and positive thermal expansion (PTE) effects can be tuned by varying the copper content of the mixed-metal cyanide, even though the substitution has little apparent effect on the structure. For example, CuNi(CN)4 shows significant intralayer NTE combined with very high PTE in the third dimension (both effects are larger than those in the parent Ni(CN)2) whereas (Cu0.50Ni1.50)(CN)4 shows zero NTE. We wish to determine the reasons for these behaviours by examining the differences between the phonon density of states for the different compositions.