Using long cables with your PA system

Glenn from New York asked another question today about running┬álong cables in a PA set up…

Do you think I need to use a direct box to make the connection to the PA, especially if the cable run is long?

Hi Glenn

The problem with using long cables is that they can adversely affect the sound. Usually you’ll notice a reduction in volume, but sometimes the quality of your sound can be degraded as well.

Generally, you’ll find you can run cables up to 10 feet or thereabouts before you start to notice any real drop in volume. And that’s a problem that’s easily fixed.

If the long cable is from your amplifier to the speaker, then as long as you have plenty of extra power in your amplifier, you can just drive the amp a little harder and it’ll compensate for any power loss the long cable may be causing.

Similarly, if the long cable is from your audio device to the mixing desk, then a bit of extra gain on the output of the audio device or turning up the gain/trim on the mixing desk channel will compensate.

But if you start to get unwanted noise, either from the long cable itself, or just from the fact that the mixer is boosting the input signal by so much, then a DI box is the answer.

Personally, if it’s only now and again you will be running cables over a distance (and you haven’t noticed any noise problems from running long cables beofre), I’d continue to use long cables rather than having to invest in a DI box and all the extra setting up etc that will take.

However, if you’re going to be regularly running long cables or you have unwanted noise in your system, a DI box may be a worthwhile investment.