Transducers are the only devices that change energy from one form to another. Most home systems have two of these, speakers and phono cartridges. Loudspeaker/cartridge making requires understanding a full array of disciplines including materials science, magnetics, acoustics and electronics. A true physics puzzle. Designing/building a quantity of "A level" speakers is not something one takes on casually. The cost of manufacturing everything yourself is so high that few can do it. Most transducer makers today are kit builders, focusing on something the end user values beyond sonic virtue (like cosmetics). There are bargains (where value is far greater than cost) at all levels of the business, from inexpensive to expensive. These bargains always punch above their weight with any set of electronics, achieving extreme performance levels only when everything in the chain is extremely good.
Brad