Help With XLR Speaker Cables

**mdainsd** · 01-30-2013

1) Disconnect the cables from the speakers and turn their gain all the way up. Noise? Yes, then self noise from internal amplifier. No, go to step 2.
2) Turn gain down on speakers, plug in cable but leave other end disconnected. Turn gain all the way up. Noise? Yes: cable is suspect. No: noise being generated by mixer. Check gain structure.

**Chili** · 01-30-2013

Originally Posted by mrcountry

but the guy at the music store is telling me that the noise is probably that the cables are actually not speaker but microphone cables.

That's frikkin hilarious!!!

Why don't I run into these idiots at the music store??

**mjbphotos** · 01-30-2013

Originally Posted by Chili

That's frikkin hilarious!!!

Why don't I run into these idiots at the music store??

Visit Guitar Center more often!

**witzendoz** · 01-30-2013

Originally Posted by mdainsd

1) Turn gain down on speakers, plug in cable but leave other end disconnected. Turn gain all the way up. Noise? Yes: cable is suspect. No: noise being generated by mixer. Check gain structure.

Well not really, as there is an open connection at the end of the cable, the XLR plug, that can induce noise depending on the surrounding RF, like a disconnected guitar cable that is still plugged into an amp.

I think some of the confusion is that the cables keep getting called XLR speaker cables, which they are not, they are XLR shielded cables (mic/line) as speakers with their own power amp does not use any form of speaker cable. A speaker cable goes between a power amp and an unpowered speaker and is standard flex not shielded.

alan.

**ecc83** · 01-30-2013

The test is to set the system up for normal sound levels and then unplug the XLR* from the speakers. If any noise, hiss is evident at the normal listening distance from BOTH speakers that is inherent "self noise". Deplorable but rather common in powered speakers and monitors I find. Very few manufacturers specify self noise and Mackie are no exception. They give a S/N ratio for the amps (and not a very good one at that!) but that means Jack without the speaker sensitivity.

If only one speaker is hissing you have a faulty amplifier and it needs attention.

My bet is you have the gain staging wrong.

*No competently designed amplifier. line or mic should produce excessive noise when the input is open circuited (Behringer can do it on my 802 mixer!). Depending upon the exact design, noise might increase a bit but a few dB above what should be buggerall should be barely noticeable. Even the O/C end of an XLR should not cause a problem since, unlike a jack, the pins are still inside a metal screen.

Dave.

**gecko zzed** · 01-30-2013

Originally Posted by ecc83

Deplorable but rather common in powered speakers and monitors I find.

Curiously, I have pairs of EV, DB Technologies and Yamaha powered speakers, and for all three, self-noise is negligible, to the extent that I can't tell they are on unless I stick my ear right into the horn.

**Bobbsy** · 01-30-2013

Originally Posted by gecko zzed

Curiously, I have pairs of EV, DB Technologies and Yamaha powered speakers, and for all three, self-noise is negligible, to the extent that I can't tell they are on unless I stick my ear right into the horn.

Ditto. Even with really big PA stacks using powered speakers, I can usually only just detect a slight hiss by getting right up against the horn/HF Driver. However, I can change this by messing up the gain staging earlier on of course....

**ecc83** · 01-30-2013

Originally Posted by gecko zzed

Curiously, I have pairs of EV, DB Technologies and Yamaha powered speakers, and for all three, self-noise is negligible, to the extent that I can't tell they are on unless I stick my ear right into the horn.

As things should be Gecks! I sit within 1/2 mtr of my Tannoy 5as and not a peep! (not that *I* could tell but Son soon would!) There is absolutely no reason today for any amplifer/speaker combination to have audible noise at its working distance. Even guitar amplifiers can be made "operationally" noise free (of course when very high gain overdrive effects are engaged, noise WILL intrude but that's just physics!).

I hasten to add that I do not have vast experience of PA and monitor systems! No, my data comes from many years of reading about this problem in forums like this. 50% of cases prove to be hum/data loops and some gain staging errors but many are just noisy fekkin' speakers!

Dave.