Reverse FM Interference - Subwoofer Revenge?

[jrhanko]

Ive been reading forums all over the interweb, and I can't seem to find a post with a similar problem... Ive seen 80 hundred posts where an FM station is interfering with their subwoofer, but my problem is the reverse...
In my case the subwoofer seems to be interfering with my radio reception. Most of the time I get horrible FM radio reception when my subwoofer is on. If I unplug or switch off the subwoofer I suddenly have clear radio reception. Ive tried running an extension cord to a different outlet and that doesnt seem to make a difference, the reception is still crappy.
Unplugging the RCA cable between the receiver and subwoofer doesnt have any effect.
The subwoofer also doesnt seem to interfere with my TV reception at all, and the subwoofer/receiver is parked right underneath the TV and TV antenna (yeah yeah, some of us can't afford cable - at least broadcast TV is HD now ).
I have a JBL E250P subwoofer plugged into a Yamaha RX-V657 receiver using standard $5 RCA subwoofer cable.
Please help?

 

[Adam]

Welcome to the forum!

I came across this website that might be helpful in general to you.

FM and TV signals are on different frequencies, so the fact that the TV broadcasts aren't noticeably affected doesn't mean that the sub isn't generating a near-field interference that is disrupting your FM reception. If you haven't already, try moving the sub across the room, plug it in, and see if you still have FM interference. I'm not saying that's the solution, as you probably want to locate the sub for performance and aesthetics. However, it might help you figure out if the proximity of the sub is causing the issue.

How close is your sub to the receiver and the FM antenna? What type of FM antenna are you using?

BTW, I also only get TV using an over-the-air antenna! I can afford cable...I just don't want it.

 

[jrhanko]

Thanks for the welcome!
Well I dont really feel like moving the sub (its heavy and Im lazy), and plus re-locating it isnt really an option due to the reasons you mention. I did move the antenna as far away as I could tho and it seemed to help a little.
The sub is probably six feet to right of my receiver, and Im just using the wire FM antenna that came with my receiver. Are there aftermarket ones that might work better?

 

[Adam]

There are aftermarket FM antennas, as well as do-it-yourself designs (like this one here).

Your TV antenna may also be tuned for FM. Can you connect that antenna to the receiver? It will depend on what type of connection you have on the receiver for the antenna. If you have questions about that, just let us know which receiver you are using. If you can connect it, give that a shot.

 

[TLS Guy]

Ive been reading forums all over the interweb, and I can't seem to find a post with a similar problem... Ive seen 80 hundred posts where an FM station is interfering with their subwoofer, but my problem is the reverse...
In my case the subwoofer seems to be interfering with my radio reception. Most of the time I get horrible FM radio reception when my subwoofer is on. If I unplug or switch off the subwoofer I suddenly have clear radio reception. Ive tried running an extension cord to a different outlet and that doesnt seem to make a difference, the reception is still crappy.
Unplugging the RCA cable between the receiver and subwoofer doesnt have any effect.
The subwoofer also doesnt seem to interfere with my TV reception at all, and the subwoofer/receiver is parked right underneath the TV and TV antenna (yeah yeah, some of us can't afford cable - at least broadcast TV is HD now ).
I have a JBL E250P subwoofer plugged into a Yamaha RX-V657 receiver using standard $5 RCA subwoofer cable.
Please help?

The problem is that class D amps are renowned for generating RF interference.
Your only practical solution is to increase your FM signal at your tuner, so the FM rejection can work better. Your best solution, is a high gain roof antenna, which every FM receiver deserves anyway.

 

[highfigh]

If you can't do a roof top antenna, try a set of rabbit ears from a TV.

 

[TLS Guy]

If you can't do a roof top antenna, try a set of rabbit ears from a TV.

That won't give him nearly enough gain. He will need a oft antenna at the minimum. However you really can't get high quality FM reception without a roof top antenna.