The Complete Handbook of Musical Instrument Amplifier Cabinets

Chapter 1: Understanding Musical Instrument Amplifier Cabinets

An amplifier cabinet—or “cab”—is the enclosure that holds the loudspeakers for your guitar, bass, or keyboard amplifier. It is the final and most audible stage of your signal chain, and it has an enormous effect on how your instrument sounds to you and to everyone else. It is not just a wooden box. It is a mechanical system that shapes sound through its size, the wood it’s built from, its internal volume, whether it is sealed or open, and the speakers it houses. Choosing one without understanding these basics is like picking a chef’s knife solely by the handle color. It might look right, but the performance will be a daily disappointment.

This handbook is a practical reference for working with these cabinets. The goal is to give you the knowledge to confidently buy, use, fix, and understand them. You will learn the physics that apply on a real stage, not academic theory you’ll never use.

What’s Inside the Box: The Speaker’s Basic Function

The heart of a cabinet is the speaker driver. A driver is a transducer: it converts electrical energy from your amplifier into mechanical energy (the movement of the cone) which then moves air, producing sound. The driver consists of a stationary permanent magnet and a moving voice coil. The current from your amp flows through the coil, which sits in the magnet’s field. When the signal shifts, it produces a force that pushes the coil and the attached cone