I have a customer who we wired for sound throughout his house with an intellinet system which works fine but about once a month at 3 or 4 in the morning the bedroom speakers will start playing very faintly a local christian radio station, just enough to wake him and his wife, by 5 or 6 the music is gone and does't happen any other time. i figured this is happing due to an atmospheric bounce but how can i stop it???? We always use good quality cl rated speaker wire and keep our wires away from electric so we can keep any noise out but i can't do much about mother nature. any ideas????

One suggestion: Get a couple of the clamp-on ferrite core chokes, and put them on the speaker wires, near the amp or receiver. An extra wrap of the wire through the core will increase the effectiveness of the filter.

Often, the output transistors will "detect", or rectify, strong RF signals picked up by extended speaker wires, which act as antennae, and the amp then amplifies the signal. The choke shunts the high frequencies.

Larry
www.fineelectricco.com

Sounds to me like someones trying to tell him something.

Yea thats what I'm saying. That would just be too much for me if I started to hear christian music at 3am every night. I may have a lifestyle change.

If what Larry suggested doen't correct the problem, try to ground the Amp also.
Mister. T

another approach is to place a VERY small, about .001 microfarad ceramic capacitor, in parallel with the speaker wires, as close to the amp as possible.

The capacitor needs to be of a low value because a)more is not needed and b)a lot of capacitance on an amp output sometimes causes amps to oscillate at inaudibly high frequencies. Take a scope out and see what happens; a blown tweeter is a good but wasteful indicator of oscillation.

I am not familiar with the intellinet system, so -- does each room have its own power amp? If so, do ALL the speakers in the house play this signal, but they have only notice it in the one room because they are not likely to start troubleshooting at 3 a.m.?

I had an interesting one once... a subwoofer would pick up a radio staion and play it at of course, a very low level. All you had to do was plug the subwoofer into the wall at ANY location in the house, plug no audio signal into it... just turn it on. The clients would hear this very low voice at night (it was talk radio). During the day, the ambient noise would drown it out.

Rather than spend hours troubleshooting, our first inclination was to try a different sub... problem fixed. The offending Infinity sub now bumps away in our office and since we try not to be there at three in the morning... we haven't noticed whether it still plays transistor radio.

AM radio is a strange bird. At night, many stations, those airing talk shows in particular, go clear-channel, which means that they're the only station on that frequency nation-wide, and boost the transmission power.

Another possibility is nearby CB users, who often illegally amplify their transceivers' outputs for greater range, too. The bleed-through can cause a lot of spurious sounds from nearby electronics.

When my son was a tot, his baby monitor played our neighbor's ratchet-jawing plain as day, as did the small stereo in his room, and one of our TVs.

Larry
www.fineelectricco.com

Thanks for all your help, i'm going next week to try one or all solutions,,,,,we'll see what happens. If all else fails i'll send them to church to try improving their relationship with the big guy.