why is this speaker doing this?

1. 2018-05-05 at 10:09 AM UTC

   #1
   The Self Taught Man Black Hole
   I had this lab for school where we had to make a circuit for a speaker with an input jack and volume knob (a potentiometer), and solder it all together and shit. Anyways we got ours all soldered up and working but it's doing something that surprises me. When there is no audio input, it plays a radio station, which we found was 94.1, not sure if that is relevant at all but it seems like it might be. Anyways does anyone know why this might be? Like wtf is causing that frequency in particular to be input to the speaker?
2. 2018-05-05 at 10:48 AM UTC

   #2
   The Self Taught Man Black Hole
   its probably the strongest signal in the area.
   
   Of course some cheap piece of shit ghetoo-rigged speaker is going to pick up interference. It probably has zero shielding and shit grounding.
   The following users say it would be alright if the author of this post didn't die in a fire!

   • aldra
3. 2018-05-05 at 11:35 AM UTC

   #3
   

   Tyrone Shoelaces Houston
   RadioShack
4. 2018-05-05 at 11:35 AM UTC

   #4
   

   aldra JIDF Controlled Opposition

   Originally posted by Misguided Russian its probably the strongest signal in the area.
   
   Of course some cheap piece of shit ghetoo-rigged speaker is going to pick up interference. It probably has zero shielding and shit grounding.

   
   probably some bare wire in there acting as an antenna too
5. 2018-05-05 at 3:54 PM UTC

   #5
   

   Soyboy African Astronaut [relevantly rival my dehydroretinol]
   It's kinda odd that you're picking up FM radio with your speaker, I thought that only worked for AM?
   
   Radio-waves basically cause tiny currents to flow in pieces of wire or other conductors, that's how they work, and everything gets affected - that's why the world around you has so much metal shielding, enhancementing capacitors, front-end diodes, twisted pair cables, and the like.
6. 2018-05-05 at 4:50 PM UTC

   #6
   

   Rock_N_Rollover African Astronaut [my obsessively old-time raunch]
   Do you wear braces?
   
   Put your tongue on it and see what station you get. Maybe another dimension.
   
   Temporarily though.
7. 2018-05-05 at 5:59 PM UTC

   #7
   

   NARCassist gollums fat coach

   Originally posted by I Live In Your Crawlspace Secretly2 I also thought that phenomenon only occurred with AM signals. Maybe they have a sister station that plays the same content on an AM channel?
   
   I think on gilligans island there was an episode where Gilligan was picking up radio signals with a tooth filling which goes to prove it is possible.
   
   As far as why that particular channel, I think it would have to do with the frequencies wavelength matching up with some of the wiring on your project. ( cant remember but i think 1:1 or maybe 2:1 etc would match up?)

   
   I've been using an old reprogrammed Prototype Series 1000 Terminator unit plugged into my laptops usb port to pick up satellite stations from all over the world, for quite a few years now.
   
   
   
   .
8. 2018-05-05 at 6:51 PM UTC

   #8
   The Self Taught Man Black Hole

   Originally posted by MORALLY SUPERIOR BEING It's kinda odd that you're picking up FM radio with your speaker, I thought that only worked for AM?
   
   Radio-waves basically cause tiny currents to flow in pieces of wire or other conductors, that's how they work, and everything gets affected - that's why the world around you has so much metal shielding, enhancementing capacitors, front-end diodes, twisted pair cables, and the like.

   
   Yea, this is kind of what I was looking for. I spend a lot of time studying electromagnetic waves but it occurred to me when I wrote this post that I'm not sure how radio waves transfer energy into devices. So what happened in this specific case is that the signal at 94.1 MHz caused a current to flow in the speaker? How does it cause a current to flow?
9. 2018-05-05 at 6:53 PM UTC

   #9
   The Self Taught Man Black Hole
   MORALLY SUPERIOR BEING
   
   wtf lanny
10. 2018-05-05 at 6:54 PM UTC

    #10
    

    Soyboy African Astronaut [relevantly rival my dehydroretinol]

    Originally posted by greenplastic Yea, this is kind of what I was looking for. I spend a lot of time studying electromagnetic waves but it occurred to me when I wrote this post that I'm not sure how radio waves transfer energy into devices. So what happened in this specific case is that the signal at 94.1 MHz caused a current to flow in the speaker? How does it cause a current to flow?

    
    The thing is that 94.1MHz radio is most likely FM (Frequency Modulation), and to pick up FM you usually need a special circuit.
    
    FM radio modulates the frequency slighly, while AM (Amplitude Modulation) radio modulates the signal strength, it's more like an electrical signal and gets picked up by simple circuits easier.
11. 2018-05-05 at 7 PM UTC

    #11
    The Self Taught Man Black Hole

    Originally posted by MORALLY SUPERIOR BEING The thing is that 94.1MHz radio is most likely FM (Frequency Modulation), and to pick up FM you usually need a special circuit.
    
    FM radio modulates the frequency slighly, while AM (Amplitude Modulation) radio modulates the signal strength, it's more like an electrical signal and gets picked up by simple circuits easier.

    
    Hmm yea I don't know. The circuit wasn't anything special at all, an op amp and a bunch of capacitors basically. I'll have to ask about this in class because I feel like it's beyond my grasp at this moment. Or maybe just wait until I sober up.
12. 2018-05-06 at 8:27 PM UTC

    #12
    

    Grimace motherfucker [my enumerable hindi guideword]
    Interference and shit grounding.
13. 2018-05-06 at 9 PM UTC

    #13
    

    benny vader YELLOW GHOST
    without circuit diagram its not worth discussing.