Since sag again someone is the cable care

I have a sound system from 2 Canton Chrono 509, 2 stereo speakers with 50W ancient Jamo and a Yamaha RS 700 as an amplifier. As a self-made subwoofer is used (look for times to "Mivoc AWX 184 GHP). Overall, the system plays a very dynamic and also makes correctly at high levels of fun. So far I had a cheap cable of equal length in use. For about 10 minutes I use this cable. Contrary to my expectation, the signal is not much more, at any rate, the whole hardly louder. Still, I can now go much higher level. Why? The quality is many times higher. Even the most nightclubs would envy in volumes is the sound wonderfully clean and differentiated. So must the. Vorhar what the sound at some point so dirty that one could hardly speak of "listening pleasure". But not only the "Monitor" you can hear a difference. Even during normal can be seen now hear details which one up to this point remained silent. And I thought I would have expected from the sound system too much. Before we had loud noise even if no device was connected. This has now disappeared. A great cable for a great price.
I always thought the cables are irrelevant, but I was taught. So: if you hundreds of euros per component outputs not very save the Cable!