Power cables connect your hi-fi system to a power source by transmitting the power signal from the power outlet to the source. They should be able to carry large peak current, while being as "neutral" as possible, with the least possible electrical interference or mechanical noise. This makes for optimum sound quality. Superb quality conductors, connectors, shielding and insulation are vital for ultra low loss power conduction. Further, for a hi-fi system to perform to its highest potential, power cables must have the lowest possible ground resistance and the correct geometry.
No matter how good your hi-fi system, it's only as good as the interconnects you use. They transmit the delicate, low-level electrical signal from the source components to the preamp or integrated amplifier. Beside superb quality conductors, connectors, shielding and insulation, the quality of the capacitance is vital in interconnect cables. A low quality capacitance in cables can cause distortion in the higher frequencies of the recording. This, in turn decreases the openness of a Hi-Fi system. On the other hand, a low ground impedance is needed to keep the interferences levels in the cables low.
Like other cables, loudspeaker cables don't make a hi-fi system sound better than it actually is. However, they can and must ensure that the full potential of the audio signal amplified by the amplifier makes its way to the speakers. The current in loudspeaker cables can be quite high in amplitute. If not well-designed, these cables can act as a noise source for other components of the hi-fi system.
Loudspeakers convert electrical signal into sound pressure. However, different tones have a different pressure and a different pressure means a different spread of frequencies. This is why one of the biggest challenges in loudspeaker cables is to bring focus to the signal, so it does not spread around in random directions and cause distortion of the sound.
Digital Interconnects are used when streaming music, for example with a network cable, USB cable or any other type of digital connection. In essence, digital cables transfer 0’s and 1’s. One of the most important factors in this transfer is timing. If the 0's and 1's are transferred to the amplifier with a delay, the sound gets distorted. This is what is called "jitter". Jitter in cables can be prevented by good grounding, shielding, connectors and overall construction of the cables. Optimizing the construction of digital cables can be an intensive and costly process, but is absolutely necessary for streaming music at the highest level.
Having good cables in your hi-fi system to get the best out of it is a must. Good cables retain essential dimensions of sound as it was recorded, such as volume, highness and lowness of tones, rhythm and musical flow and the distance between instruments. But cables shouldn't stop there. They have to retain as much of the details of the recording environment as possible - to transfer the scene and virtually place you in the room with the artists.