Foundations

A higher note does not travel faster than a lower one. Two loudspeakers playing the same signal do not automatically produce a stable image between them — moving six inches can collapse it. The inner ear does not respond to every frequency at once; it sorts them by physical position along a spiral before any interpretation begins. Most systems get adjusted, replaced or blamed for problems that are actually happening here, in physics and hearing most listeners were never taught.

This volume teaches that layer directly: how sound behaves as a wave, how two ears turn pressure into direction and space, how a loudspeaker’s own physics set real limits before a room ever gets involved, how digital audio actually represents a waveform, and how the whole chain — source, amplifier, loudspeaker, room, ear, brain — has to be understood as one connected system rather than a list of separate boxes.

It does not choose equipment, optimise a room, or fix a fault — those are separate, practical volumes, built on what’s established here. What it gives instead is the vocabulary and the physical understanding that make the rest of the series possible to apply with evidence instead of folklore.

This volume lays out the ideas the rest of the series builds on. If a system is already working well and the aim is simply to get more from what’s already there, the fuller, cross-domain treatment of that — spanning both audio and picture — is Volume II, Practical Optimisation.