Signal power is "old school" termination philosophy. The strategy back then was to maximize "power" transfer that occurs when source impedance and load impedance is equal. Back in the day the standard interface was 600 ohms outputs and inputs. We still see 600 ohm terminations on old legacy equipment.Newmarket said:And that illustration is confusing as it discusses 'signal power' that isn't really a 'thing' in line level interconnection where we are looking at the voltage and need only enough current to produce that at the load.
To be fair it does go on to discuss more standard Lo-Z outputs / Higher Z loads but I do see that the article could be misleading and the other technical flaws that have been highlighted.
The old power transfer model has been superseded by a maximum voltage transfer philosophy AKA "bridging" terminations. Bridging generally stipulates at least a 1:10 ratio between source and following termination impedance.
It is not an accident the low Z mics are nominally 200 ohm source impedance and feed into mic preamp inputs with 2k ohm input terminations. Line level inputs with nominal 10k terminations are driven from 1k or less output impedances.
So power transfer "was" a thing, but now voltage transfer is the focus.
JR