4 ms·

> Interference isn't a problem in speaker cables because it is an amplified signal, so any added noise is too little to be audible. I dispute that. Source: I c

> Interference isn't a problem in speaker cables because it is an amplified signal, so any added noise is too little to be audible. I dispute that. Source: I could hear at a previous apartment where I used to live that something was off when I was listening to music. It was subtle, but it was there. It drove me mad until I realized that by lifting the speakers cable off the floor the interference was gone. I don't care about the science in this case. I just don't for I've witnessed it myself (well, heard it really). I've tested my theory (lifting the cable of the ground) and repeated the experiment. It is a fact (for you it may just be a comment on the Internet, but for me it is factual). Putting the cables on little wooden pieces I made got rid of the interference (at least I couldn't hear it anymore). That was happening on a "budget" (less than $1 K) setup (including a DAC). Very clean source: bitperfect rips of my CD collection. Quiet room. The added noise was noticeable and was perturbing the listening.

searealist 3y ago
If there was interference then you would _always_ hear it, not just when playing music. In fact, it would be significantly easier to hear it when not playing music.
- kenhwang 3y ago
  Yes, it's annoying and only very noticeable when the speakers were supposed to be silent, but weren't and hissed and hummed instead. Swapped for better shielded cables and the hiss/hum went away and it was dead silent when it was supposed to be. But it was also only noticeable on the satellite speakers that had 50ft+ cable runs. It was inaudible on those short <6ft runs.
  - searealist 3y ago
    Can you please link the cables you purchased?
- mlyle 3y ago
  Weird things can happen. If you pick up RF on the speaker wire, it can make the output stage of the amplifier nonlinear in weird ways. The extreme case is when you can receive radio signals on the speaker wire that are rectified and amplified by the amplifier; but you can get wonkiness short of that.
  - searealist 3y ago
    This is not an issue for anyone. https://www.youtube.com/watch?v=gL4O_Do2PuQ https://www.youtube.com/watch?v=gL4O_Do2PuQ
    - mlyle 3y ago
      I've fought these arcane issues before. I don't have a ton of experience in audio, but I've seen them at lower frequencies (in servo amplifiers, where rectified RF causes DC offsets) and higher frequencies (as intermodulation in RF amplifiers from strong out-of-band interfering signals). This is why you find things like this in design manuals. These are focused on offset errors in instrumentation amplifiers hooked to long cables (but intermodulation is an equal or larger concern in applications that care about frequencies above DC): "In addition to filtering the input and power pins, amplifier outputs also need to be protected from EMI/RFI, especially if they must drive long lengths of cable, which act as antennas. RF signals received on an output line can couple back into the amplifier input where it is rectified, and appears again on the output as an offset shift." https://www.analog.com/media/en/training-seminars/tutorials/mt-096.pdf https://www.analog.com/media/en/training-seminars/tutorials/... Microchip says the same thing: "Amplifier outputs also need to be protected from EMI/RFI, especially if they must drive long lengths of cable, which act as antennas. RF signals received on an output line couple back into the amplifier input where they are rectified and appear again on the output as an offset shift." https://ww1.microchip.com/downloads/en/appnotes/00001767a.pdf https://ww1.microchip.com/downloads/en/appnotes/00001767a.pd... https://www.physicsforums.com/threads/how-does-an-amplifier-inadvertently-demodulate-a-radio-signal.870029/ https://www.physicsforums.com/threads/how-does-an-amplifier-... post #4 Note that I'm not really saying you need anything special on speaker cables, other than common sense: don't separate the pair for as much of the run as possible, and make sure the terminations at the end are not total garbage. If you have strong RF sources nearby, like when I had a 50W HF transmitter in my apartment, you may need to add RF chokes/ferrites on the amplifier end of speaker cables to reduce interference (I did). Indeed, the ARRL (American Radio Relay League, an amateur radio association) describes that adjusting speaker cables is a frequent way to cure interference for neighbors of people with high power transmitters: "Speaker wires are often 8 to 16 feet long. When you put two of them together, you make an efficient receiving antenna. Try bundling the speaker wires to reduce their effectiveness as an antenna. This procedure has been known to eliminate the interference all by itself." "A: For a detailed explanation, you can refer to the ARRL Handbook's section on controlling RFI, and the section of the ARRL web site on EMI/RFI Products and Other Resources. You can build two of them, one for each speaker output. Wrap ten to fifteen turns of speaker wire onto an FT-140-43 ferrite core. Use an FT-240-43 if the speaker wires are large, and use "73" material for interference from 80 or 160-meter signals. Alternately, type "31" material is an excellent general purpose choice for HF. Install them right at the amplifier. If the system uses amplified speakers, you should install one at each speaker, too." https://www.arrl.org/audio-1 https://www.arrl.org/audio-1

searealist 3y ago

If there was interference then you would _always_ hear it, not just when playing music. In fact, it would be significantly easier to hear it when not playing music.

kenhwang 3y ago
Yes, it's annoying and only very noticeable when the speakers were supposed to be silent, but weren't and hissed and hummed instead. Swapped for better shielded cables and the hiss/hum went away and it was dead silent when it was supposed to be. But it was also only noticeable on the satellite speakers that had 50ft+ cable runs. It was inaudible on those short <6ft runs.
- searealist 3y ago
  Can you please link the cables you purchased?
mlyle 3y ago
Weird things can happen. If you pick up RF on the speaker wire, it can make the output stage of the amplifier nonlinear in weird ways. The extreme case is when you can receive radio signals on the speaker wire that are rectified and amplified by the amplifier; but you can get wonkiness short of that.
- searealist 3y ago
  This is not an issue for anyone. https://www.youtube.com/watch?v=gL4O_Do2PuQ https://www.youtube.com/watch?v=gL4O_Do2PuQ
  - mlyle 3y ago
    I've fought these arcane issues before. I don't have a ton of experience in audio, but I've seen them at lower frequencies (in servo amplifiers, where rectified RF causes DC offsets) and higher frequencies (as intermodulation in RF amplifiers from strong out-of-band interfering signals). This is why you find things like this in design manuals. These are focused on offset errors in instrumentation amplifiers hooked to long cables (but intermodulation is an equal or larger concern in applications that care about frequencies above DC): "In addition to filtering the input and power pins, amplifier outputs also need to be protected from EMI/RFI, especially if they must drive long lengths of cable, which act as antennas. RF signals received on an output line can couple back into the amplifier input where it is rectified, and appears again on the output as an offset shift." https://www.analog.com/media/en/training-seminars/tutorials/mt-096.pdf https://www.analog.com/media/en/training-seminars/tutorials/... Microchip says the same thing: "Amplifier outputs also need to be protected from EMI/RFI, especially if they must drive long lengths of cable, which act as antennas. RF signals received on an output line couple back into the amplifier input where they are rectified and appear again on the output as an offset shift." https://ww1.microchip.com/downloads/en/appnotes/00001767a.pdf https://ww1.microchip.com/downloads/en/appnotes/00001767a.pd... https://www.physicsforums.com/threads/how-does-an-amplifier-inadvertently-demodulate-a-radio-signal.870029/ https://www.physicsforums.com/threads/how-does-an-amplifier-... post #4 Note that I'm not really saying you need anything special on speaker cables, other than common sense: don't separate the pair for as much of the run as possible, and make sure the terminations at the end are not total garbage. If you have strong RF sources nearby, like when I had a 50W HF transmitter in my apartment, you may need to add RF chokes/ferrites on the amplifier end of speaker cables to reduce interference (I did). Indeed, the ARRL (American Radio Relay League, an amateur radio association) describes that adjusting speaker cables is a frequent way to cure interference for neighbors of people with high power transmitters: "Speaker wires are often 8 to 16 feet long. When you put two of them together, you make an efficient receiving antenna. Try bundling the speaker wires to reduce their effectiveness as an antenna. This procedure has been known to eliminate the interference all by itself." "A: For a detailed explanation, you can refer to the ARRL Handbook's section on controlling RFI, and the section of the ARRL web site on EMI/RFI Products and Other Resources. You can build two of them, one for each speaker output. Wrap ten to fifteen turns of speaker wire onto an FT-140-43 ferrite core. Use an FT-240-43 if the speaker wires are large, and use "73" material for interference from 80 or 160-meter signals. Alternately, type "31" material is an excellent general purpose choice for HF. Install them right at the amplifier. If the system uses amplified speakers, you should install one at each speaker, too." https://www.arrl.org/audio-1 https://www.arrl.org/audio-1