We assess the possibility that baryonic acoustic oscillations in adiabatic models may explain the observations of excess power in large-scale structure on 100 h ^ { -1 } { Mpc } scales .
The observed location restricts models to two extreme areas of parameter space .
In either case , the baryon fraction must be large ( \Omega _ { b } / \Omega _ { 0 } \simgt 0.3 ) to yield significant features .
The first region requires \Omega _ { 0 } \simlt 0.2 h to match the location , implying large blue tilts ( n \simgt 1.4 ) to satisfy cluster abundance constraints .
The power spectrum also continues to rise toward larger scales in these models .
The second region requires \Omega _ { 0 } \approx 1 , implying \Omega _ { b } well out of the range of big bang nucleosynthesis constraints ; moreover , the peak is noticeably wider than the observations suggest .
Testable features of both solutions are that they require moderate reionization and thereby generate potentially observable ( \sim 1 \mu K ) large-angle polarization , as well as sub-arc-minute temperature fluctuations .
In short , baryonic features in adiabatic models may explain the observed excess only if currently favored determinations of cosmological parameters are in substantial error or if present surveys do not represent a fair sample of 100 h ^ { -1 } { Mpc } structures .