We describe several techniques for constructing \(n\)-dimensional Hadamard matrices from \(2\)-dimensional Hadamard matrices, and note that they may be applied to any perfect binary array \((PBA)\), thus optimally improving a result of Yang. We introduce cocyclic perfect binary arrays, whose energy is not restricted to being a perfect square. These include
all of Jedwab’s generalized perfect binary arrays. There are many more cocyclic \(PBAs\) than \(PBAs\). We resolve a potential ambiguity inherent in the “weak difference set” construction of \(n\)-dimensional Hadamard matrices from cocyclic \(PBAs\) and show it
is a relative difference set construction.