It is generally believedthat the glasses andcrystals d iffer very much from each other by their vibrational spectra. However, the crystalline systems with frozen disorder may exhibit the vibrational density of states (DOS) peaked in low-energy region quite resembling to the Bose peak typically observedin glasses. Common origin of these features in disordered crystalline and amorphous systems is discussed in the frameworks of two theoretical concepts: the soft potential and the broken ladder models. The experimental results are presented for large series of standard, oxygen deficient, layered perovskite-based systems and systems containing the metal-oxygen chains. They were studied with using the nuclear ð 57 FeÞ inelastic scattering of synchrotron radiation. The largest excess of vibrational density of states with respect to the Debye-like one was foundin the brownmillerite CaSrFeCoO 5 with the peak energy 7:5 meV: The peak in E � 2 -weightedDOS gðEÞ=E 2 exceeds the Debye behavior ðgðEÞpE 2 Þ by C4 times at room temperature and