RFI help stop the insanity

[129Decibel]

Hey everyone, Problem is every winter same old RFI ! Some station plays thru my speakers loud enough that you can hear it when the music plays. Tried just about everything Panamax, triplight, those magnet thingys, new rca cables. The left speaker is the worse during the softer parts of the music you can hear whatever is on that station at the time totally ruins a good jam. What will work to stop this?

[DeZZar]

If you move your speaker cables around during this interference does it change at all? (e.g. lift them up, shorten them, bunch them up etc etc) Just a way to try find where its being picked up. Something is acting like an antenna.

[billfitzmaurice]

Speaker cables aren't the problem. For the RFI to be heard it must be amplified, so it's being picked up somewhere in the signal chain. In theory you could report it to the FCC and they'd investigate, but I wouldn't count on it. The way to trace it is to disconnect everything, then hook it up one piece at a time, working backwards from the speakers. At some point you'll hook up something and the unwanted music will commence.

[Paul Carmody]

Do you have one of the following?
1. A really long line-level RUN (ie: RCA)?
2. Something with a coaxial hookup in the chain?

[129Decibel]

I'm running preouts from my yamaha AVR amp to a pair of carver silver 9t's. Short rca cable none over 3ft long 30 ft speaker cable, carver recommends long rca short speaker cables why?. Both L and R speaker wires are the same length the left is closest to the amp so there is bout 9ft of extra wire the L is the speaker with the loudest RFI. I haven't tried taken the carvers out of the loop yet I'll mess with the other cable first unplug some things. So can lets say the cd player cause this or crossed wires power cable across speaker wires etc. There are 9 speakers in all and only the ones running thru the carvers are affected by RFI .

[Mike C]

What happens when you disconnect the inputs from the amp?
Does the RFI quit when you turn the power off on everything?
How close are you to the radio station broadcast tower?
is it an AM or FM station that is coming through.

Try wrapping the RCA cables a few wraps around a ferrite core.....or two
https://www.parts-express.com/Ferrite-Core-1-2-Cord-Noise-Suppressor-110-454

I had an installation at a school that was very close to some TV and Radio broadcast towers
and it took a ferrite core on the incoming mic lines to clean up the RFI.

[billfitzmaurice]

Short rca cable none over 3ft long 30 ft speaker cable, carver recommends long rca short speaker cables why?.

Why indeed. Unbalanced interconnects are prone to RFI/EMI and ground loops, speaker cables aren't. In pro sound amps are placed closer to the speakers for minimal speaker cable runs but that's to reduce insertion losses, and they can have long interconnects because they're balanced.

Both L and R speaker wires are the same length the left is closest to the amp so there is bout 9ft of extra wire .

That begs the question 'Why?'. A difference in the two cables of around 0.015 ohms isn't going to be even close to audible. However, if you've got that extra nine feet of wire coiled that coil is a pair of series inductors, which could conceivably be causing back EMF.

[fpitas]

I have heard (but not personally experienced) that some amps are sensitive to RF pickup on the speaker leads. One way to minimize that is to RF terminate the speaker runs at the speaker end, as in this article:

https://sound-au.com/cable-z.htm

[fpitas]

Clamp-on ferrite cable beads may help, too.

[Mike C]

You said "Problem is every winter same old RFI" so in the summer you do not have this problem at all?

Where are you located, are your winters really dry? Could be power grounding issues, ground rod in dry dirt, AM radio RFI issues can be from grounding issues.

Do you get the RFI all the time the system is on or does it come and go?


I can say I have heard passive speakers directly pick up RFI. In that case they were stage monitors at a church and the RFI was from their lighting system,
I was working on some equipment on the stage and I kept hearing a faint buzz, I knew the sound system was turned off. I found it was coming from the horn of the stage monitors. I could disconnect the monitor, carry it around and hear the buzz changing with the position of the monitor. The coils in the crossover were picking up the RF hash from the dimmers via inductance.
The very efficient high frequency compression drivers made it easy to hear.

And yes electric guitars were noisy in there as well.

[Mike C]

"Clamp-on ferrite cable beads may help, too."

Wrapping the cable around the core and then snapping it closed works better than just
clamping it on the cable.

[fpitas]

"Clamp-on ferrite cable beads may help, too."

Wrapping the cable around the core and then snapping it closed works better than just
clamping it on the cable.

True, if the bead opening is large enough. If not, you can also use a bunch side-by-side.

[DeZZar]

If you move your speaker cables around during this interference does it change at all?

Speaker cables aren't the problem..

30 ft speaker cable, ...left is closest to the amp so there is bout 9ft of extra wire the L is the speaker with the loudest RFI..

...if you've got that extra nine feet of wire coiled that coil is a pair of series inductors, which could conceivably be causing back EMF.

¯\_(ツ)_/¯.....like, its a two second experiment to eliminate the possibility...

[billfitzmaurice]

Disconnect the speaker cables at the amp. If they're what's picking up the RFI the sound won't go away. Considering the voltage level required for said airborne RFI to be audible through the speakers I wouldn't want to be in that house for fear of Havana Syndrome.

[Steve Lee]

^
ha!

[129Decibel]

Looks like the speaker cable was the problem all bunched up and twisted separated the L R and C channels and the station went away just the slight buzz from the carvers. Also had two old sub woofer speaker wires in the wire jacket removed those, going to shorten all the wires then but them back in the jacket. Sound great again thanks for the help.