5 ms·

I know this sounds stupid, but I actually had something like this happen to me. It was due to the cable. My PC is very electrically noisy on account of the GPU

I know this sounds stupid, but I actually had something like this happen to me. It was due to the cable. My PC is very electrically noisy on account of the GPU. This noise was coming out of all the ports, including the Ethernet port. It was making it through that port, by CAT-6 cable, to my switch. The switch then sent it to my Raspberry Pi I was using as a streamer, then into my DAC, amplifier and finally speakers. You could hear it, it was loud when a game started up. The solution - swap out the CAT-6 with CAT-5 cable which doesn't connect the ground planes. Instantly solved.

Fatnino 4y ago
I have a computer that will sometimes crash hard, frozen screen and mouse, awful static on the speakers and, interestingly, something coming over the ethernet port too. This interference goes up to the next device on the line, my network switch, and brings that to its knees too. Nothing can move through the switch while that computer is having a seizure. I can disconnect the wire at the switch and the network comes back to life within a minute. I'm considering putting a sacrificial switch from my junk box inline to that one computer so maybe the rest of the network can survive its crashes.
- iforgotpassword 4y ago
  That is probably the nic in said machine still being alive and unable to pass any received frames up to the os. When its buffer runs full, it starts spamming pause frames, which dumber switches just blast out every port effectively paralyzing the whole network segment. You could verify this by running Wireshark on another machine, or try disable sending pause frames on the machine before it crashes via eg ethtool
  - darkwater 4y ago
    Mmmmh interesting. In my case just a few weeks ago I had an AP that went bananas, and was directly connected via ethernet to a RPi4, and made the Raspbian kernel panic on the Broadcom driver, randomly. Not long after the AP stopped working completely.
acje 4y ago
I think electrical engineers having done some RF designs generally regard audiophiles as flat-earthers explaining what is wrong with a flat map; they might get it right now and then, but always for the wrong reasons. Remember how in the 90ties you could hear an SMS coming to a phone near an audio device? Right! No physical connection and sure you can’t hear the 900mhz ish gsm signal, but the rectified and smoothed signal had an audible time division multiplexing (envelope). And the carrier wave often resonated with paths in the signaling path of the audio device.
- eru 4y ago
  The common term is 'GSM buzz', you'll find a lot about it online. I've also heard it in the 2000s.
  - ed_elliott_asc 4y ago
    On a Sunday morning I used to lie in with the radio on, sleeping on and off. There was one song around 1999 that included the sound and also had my ring tone. It was a very confusing time. Found it: https://youtu.be/y8ClVMzt9Dw https://youtu.be/y8ClVMzt9Dw [edit: added link]
  - yakubin 4y ago
    I heard it just a couple years ago, when I used a 2G phone. 3G and 4G don’t have that fault.
    - ed_elliott_asc 4y ago
      Fault or feature? Was nice to get some warning your phone was about to ring
- pbazarnik 4y ago
  The keywords are: EMI (electromagnetic interference), signal integrity, power integrity. Memcpy can have second order effects due to EMI radiated by CPU, motherboard or coupled via power fluctuations. There are audible and measurable effects of audio system clock jitter which in turn depends on oscillator power quality. Someone mentioned that ethernet has isolation transformers. But isolation transformers have parasitic common mode coupling which can inject the noise to ground plane if interference is strong and device is susceptible enough Watch the EEVBLOG on company which designed scope capable of measuring 1kV common mode signals. (present in EV electronics) https://youtu.be/I7ppDNLlEL4 https://youtu.be/I7ppDNLlEL4 Audiophile stuff is a weird mix of real effects and snake oil.
aforwardslash 4y ago
Hum,Im pretty sure you mean STP vs UTP, and not cat5 vs cat6. Electrically, cat5 and cat6 are equal; cat6 is slightly thicker, has a thread separator in the middle, and its rated for higher frequency. Electrically? The same. STP cable (regardless if specced for cat5 or cat6) does have a ground plane.
- Night_Thastus 4y ago
  Oh! That must have been it, thank you. I'm not very familiar, I just knew the cables were cat6 and cat5. Thought it might have something to do with the shielding. Looking over the product page, it's marked as S/FTP
  - baq 4y ago
    Yeah don’t use grounded cables if you don’t have ground to actually ground them. At least that’s what I was told once upon a time since EE is definitely not my forte.
    - aaronmdjones 4y ago
      Correct. More specifically, if a shield is not actually grounded, all it becomes is a re-radiating antenna for all of the EMI around it, as well as a means by which to directly transfer electrical noise from one device to another.
- nerdponx 4y ago
  I never see either of these terms on sites like Newegg. How do I know which is which? Which one am I supposed to use at home?
  - aforwardslash 4y ago
    The "U" stands for Unshielded, the "S" stands for Shielded. For home use and office use, UTP is fine. STP makes sense in "noisy" (electrical or magnetic) environments, such as factory floors with heavy machinery, clinics & hospitals with specific machinery, etc. See more details on the kind of protection the shielding offers here: https://en.wikipedia.org/wiki/Shielded_cable https://en.wikipedia.org/wiki/Shielded_cable
atoav 4y ago
Or better, use devices designed with a propper grounding scheme and avoid the Raspi DAC for anything critical.
- Night_Thastus 4y ago
  The raspberri pi isn't a dac, it's a streamer. It acts as a middleman to avoid using my PC as the source of the audio. I'd definitely prefer a DAC with good filtering on its inputs so I wouldn't need to use a middleman, but that is expensive. One with a proper USB module with complete isolation can run ~$5000.
IYasha 4y ago
I cannot upvote you enough, as I've been through similar problems many times. But in your case you could just re-crimp one side of your cable with unshielded connector. This is actually a good practice not only for noise and ground-loop preventions, but electrical safety too. Also, CAT.6 doesn't require shielding like FTP/SFTP/etc. - I'm using a CAT.6 UTP right now. And anti-audiophiles are sometime becoming even worse than manical audiophiles - because of their deep blind belief in their educated superiority (while in reality it's a bit .. untrue).
- rhinoceraptor 4y ago
  There's usually a grain of truth in that audiophile nonsense, that it could in theory have some material basis in reality. The problem is the complete rejection of the scientific method.

Fatnino 4y ago

I have a computer that will sometimes crash hard, frozen screen and mouse, awful static on the speakers and, interestingly, something coming over the ethernet port too. This interference goes up to the next device on the line, my network switch, and brings that to its knees too. Nothing can move through the switch while that computer is having a seizure. I can disconnect the wire at the switch and the network comes back to life within a minute. I'm considering putting a sacrificial switch from my junk box inline to that one computer so maybe the rest of the network can survive its crashes.

iforgotpassword 4y ago
That is probably the nic in said machine still being alive and unable to pass any received frames up to the os. When its buffer runs full, it starts spamming pause frames, which dumber switches just blast out every port effectively paralyzing the whole network segment. You could verify this by running Wireshark on another machine, or try disable sending pause frames on the machine before it crashes via eg ethtool
- darkwater 4y ago
  Mmmmh interesting. In my case just a few weeks ago I had an AP that went bananas, and was directly connected via ethernet to a RPi4, and made the Raspbian kernel panic on the Broadcom driver, randomly. Not long after the AP stopped working completely.

acje 4y ago

I think electrical engineers having done some RF designs generally regard audiophiles as flat-earthers explaining what is wrong with a flat map; they might get it right now and then, but always for the wrong reasons. Remember how in the 90ties you could hear an SMS coming to a phone near an audio device? Right! No physical connection and sure you can’t hear the 900mhz ish gsm signal, but the rectified and smoothed signal had an audible time division multiplexing (envelope). And the carrier wave often resonated with paths in the signaling path of the audio device.

eru 4y ago
The common term is 'GSM buzz', you'll find a lot about it online. I've also heard it in the 2000s.
- ed_elliott_asc 4y ago
  On a Sunday morning I used to lie in with the radio on, sleeping on and off. There was one song around 1999 that included the sound and also had my ring tone. It was a very confusing time. Found it: https://youtu.be/y8ClVMzt9Dw https://youtu.be/y8ClVMzt9Dw [edit: added link]
- yakubin 4y ago
  I heard it just a couple years ago, when I used a 2G phone. 3G and 4G don’t have that fault.
  - ed_elliott_asc 4y ago
    Fault or feature? Was nice to get some warning your phone was about to ring
pbazarnik 4y ago
The keywords are: EMI (electromagnetic interference), signal integrity, power integrity. Memcpy can have second order effects due to EMI radiated by CPU, motherboard or coupled via power fluctuations. There are audible and measurable effects of audio system clock jitter which in turn depends on oscillator power quality. Someone mentioned that ethernet has isolation transformers. But isolation transformers have parasitic common mode coupling which can inject the noise to ground plane if interference is strong and device is susceptible enough Watch the EEVBLOG on company which designed scope capable of measuring 1kV common mode signals. (present in EV electronics) https://youtu.be/I7ppDNLlEL4 https://youtu.be/I7ppDNLlEL4 Audiophile stuff is a weird mix of real effects and snake oil.

aforwardslash 4y ago

Hum,Im pretty sure you mean STP vs UTP, and not cat5 vs cat6. Electrically, cat5 and cat6 are equal; cat6 is slightly thicker, has a thread separator in the middle, and its rated for higher frequency. Electrically? The same. STP cable (regardless if specced for cat5 or cat6) does have a ground plane.

Night_Thastus 4y ago
Oh! That must have been it, thank you. I'm not very familiar, I just knew the cables were cat6 and cat5. Thought it might have something to do with the shielding. Looking over the product page, it's marked as S/FTP
- baq 4y ago
  Yeah don’t use grounded cables if you don’t have ground to actually ground them. At least that’s what I was told once upon a time since EE is definitely not my forte.
  - aaronmdjones 4y ago
    Correct. More specifically, if a shield is not actually grounded, all it becomes is a re-radiating antenna for all of the EMI around it, as well as a means by which to directly transfer electrical noise from one device to another.
nerdponx 4y ago
I never see either of these terms on sites like Newegg. How do I know which is which? Which one am I supposed to use at home?
- aforwardslash 4y ago
  The "U" stands for Unshielded, the "S" stands for Shielded. For home use and office use, UTP is fine. STP makes sense in "noisy" (electrical or magnetic) environments, such as factory floors with heavy machinery, clinics & hospitals with specific machinery, etc. See more details on the kind of protection the shielding offers here: https://en.wikipedia.org/wiki/Shielded_cable https://en.wikipedia.org/wiki/Shielded_cable

atoav 4y ago

Or better, use devices designed with a propper grounding scheme and avoid the Raspi DAC for anything critical.

Night_Thastus 4y ago
The raspberri pi isn't a dac, it's a streamer. It acts as a middleman to avoid using my PC as the source of the audio. I'd definitely prefer a DAC with good filtering on its inputs so I wouldn't need to use a middleman, but that is expensive. One with a proper USB module with complete isolation can run ~$5000.

IYasha 4y ago

I cannot upvote you enough, as I've been through similar problems many times. But in your case you could just re-crimp one side of your cable with unshielded connector. This is actually a good practice not only for noise and ground-loop preventions, but electrical safety too. Also, CAT.6 doesn't require shielding like FTP/SFTP/etc. - I'm using a CAT.6 UTP right now. And anti-audiophiles are sometime becoming even worse than manical audiophiles - because of their deep blind belief in their educated superiority (while in reality it's a bit .. untrue).

rhinoceraptor 4y ago
There's usually a grain of truth in that audiophile nonsense, that it could in theory have some material basis in reality. The problem is the complete rejection of the scientific method.