Here is an explanation of impedance, getting a better understanding of what a cable or componet has for impedance can and will help with system matching to obtain a synergy of balance within any given system,
Impedance
A measure of the complex resistive and reactive attributes of a component in an alternating-current (AC) circuit. Impedance is what restricts current flow in an AC electrical circuit; impedance is not relevant to DC circuits. In DC circuits, resistors limit current flow (because of their resistance). In AC circuits, inductors and capacitors similarly limit the AC current flow, but this is now because of their inductive or capacitive reactance. Impedance is like resistance but it is more. Impedance is the sum of a circuit, or device's resistance AND reactance. Reactance is measured in ohms (like resistance and impedance) but is frequency-dependant. Think of impedance as the complete or total current limiting ohms of the circuit -- the whole banana. Since AC circuits involve phase shift -- i.e., the voltage and current are rarely in phase due to the storage effects (think "time;" it takes time to charge and discharge) of capacitors and inductors, the reactance is termed "complex," that is there is a "real" part (resistive) and an "imaginary" part (bad terminology, but it means the phase shifting resistance part). To summarize: resistance has no phase shift; reactance (capacitors & inductors in AC circuits) includes phase shift; and impedance, is the sum of resistance and reactance. Just that simple.
Impedance
A measure of the complex resistive and reactive attributes of a component in an alternating-current (AC) circuit. Impedance is what restricts current flow in an AC electrical circuit; impedance is not relevant to DC circuits. In DC circuits, resistors limit current flow (because of their resistance). In AC circuits, inductors and capacitors similarly limit the AC current flow, but this is now because of their inductive or capacitive reactance. Impedance is like resistance but it is more. Impedance is the sum of a circuit, or device's resistance AND reactance. Reactance is measured in ohms (like resistance and impedance) but is frequency-dependant. Think of impedance as the complete or total current limiting ohms of the circuit -- the whole banana. Since AC circuits involve phase shift -- i.e., the voltage and current are rarely in phase due to the storage effects (think "time;" it takes time to charge and discharge) of capacitors and inductors, the reactance is termed "complex," that is there is a "real" part (resistive) and an "imaginary" part (bad terminology, but it means the phase shifting resistance part). To summarize: resistance has no phase shift; reactance (capacitors & inductors in AC circuits) includes phase shift; and impedance, is the sum of resistance and reactance. Just that simple.