Audio Systems: speacon cable thickness

Question
namaste sir,
i am runnig professional pa system rental company. i want to asked about speacon cable. i had 4 core 1.5 sq. mm 26 mtsth long cable during using i found the cable increasing ohms so i came with an idea of coverting 4 core cable to 2 core cable and thus it bacame 3.0 sq mm 2 core speacon cable. i want to asked that is it correct to use that way or not? expalin in detail.
thanks.

Answer
Connection between the output of an audio amplifier and the speaker is a function of resistance.  The distance and the resistance per linear meter is the sole determining factor.

It is suggested for professional use the resistance of the wire should be no greater than 1/10 that of the impedance of the speaker connected.

You can select the connecting wire on that basis.

However, for long runs you must be careful of interference from nearby power lines or other possible inductive interferences. (Being near unto a power line run can induce hum into the speaker system.)

For some multi wire cables you can parallel the wires to lower the resistance and it will work fine.

Audio enthusiasts who are ever so desirable to get best possible audio performance will want to keep the resistance as low as possible so as to keep the damping factor of the amp/speaker at its best.  Therefore, sometimes it is chosen to use wire or cable with multi-stranded composition which keeps the resistance and impedance very low.  Also, the purist will cut the wire as short as possible to reach to the speaker in order to keep the resistance low.  At the same time it is important to use terminals at both the amp and speaker that have low resistance.

Final comment; keeping the resistance of the wire low is the key to getting the most power into the speaker.  The higher the resistance the greater the portion of the audio power being dissipated in the connecting cable.

Let me know if you need more.