There is nothing wrong with using tone controls. They have a very valuable and specific function in a sound system. Unfortunately, audiophiles who imagine an idealized world where all recordings are made with equipment and are played back on equipment having a flat frequency response and that room acoustics don't alter audible frequency response have been convinced that they aren't necessary. Then they complain about cds sounding too shrill and speak about the "signature" of this speaker or that amplifier meaning its frequency response.

Using cables as an equalizer is a terrible idea. They are unpredictible in their effect. Even an experienced engineer having all of the necessary data would find it difficult to accurately predict what any given cable would do audibly in a sound system. Only trial and error have shown that so many of them have no effect. They are uncontrollable. You can't control which frequencies they will effect or to what degree. You are left to the mercy of hit or miss luck and it is invariably miss. They are expensive. Some of them cost hundreds or even thousands of dollars with no guarantee that they will do what you want. You can spend the rest of your life looking for just the right one. A graphic equalizer on the other hand is predictable and controllable and at a modest cost. And one other thing. Connecting loudspeaker cables with extreme electrical reactance, especially capacitance creates a risk of damage to some power amplifiers. Unless you set the controls of a graphic equalizer to their extreme positions and throw all reasonable caution to the wind, there is no risk to the rest of the system by using one. Perhaps that's why every professional sound system incorporates them.