Why 8 Ohms? – Part 3

In parts 1 and 2 of “Why 8 Ohms?” I covered the theory regarding the amplifier to loudspeaker interface. In case you need a refresher, here are links to Part 1 and Part 2. These are not prerequisites to Part 3.

Why History Matters
Many of the important characteristics of this interface are borrowed from the world of utility power distribution. As I showed in the earlier articles, this “power mindset” influenced the development of audio interfaces. In audio’s early years, the entire signal chain was interfaced for optimum power transfer. This was accomplished by impedance matching the source to the load. “Impedance matching” is practically irrelevant in modern analog audio interfaces, having been replaced by the constant voltage (CV) interface, where low impedance outputs drive high impedance inputs. This optimizes the interface for voltage transfer. This makes the signal voltage, not signal power, the quantity of interest regarding level, bandwidth, and distortion for every device in the signal chain.

In this third (and final) part of Why 8 Ohms? I’ll use the CAFViewer™ Low-Z calculator to demonstrate that you don’t have to choose between voltage and power ratings. You can have both.   pb