Preface "Unprovided with original learning, unformed in the habits of thinking, unskilled in the arts of composition, I resolved to write a book." Edward Gibbon This is believed to be the first book concentrating wholly on active crossovers--in fact, it is probably the first book that focuses exclusively on crossovers of any sort. In a field where any sort of consensus is rare, there is general agreement that audio systems with active crossovers and multiple amplifiers to drive the loudspeakers sound unquestionably better than their passive crossover counterparts. I think that the use of active crossovers may well be the next big step in hi-fi, and that was part of my motivation for writing this book. The use of active crossovers in sound reinforcement is also very fully covered. You might think that active crossovers are a narrow field for a book, but actually the scope of the subject is rather wider than it sounds. There is a lot of material on active filters, low-noise design, and generally on the intelligent use of opamps, which has much wider applications. More broadly than that, there are many examples of how to tackle a problem