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Actual link to forum: https://www.audioasylum.com/messages/pcaudio/119979/ https://www.audioasylum.com/messages/pcaudio/119979/ "found that a function called m

Actual link to forum: https://www.audioasylum.com/messages/pcaudio/119979/ https://www.audioasylum.com/messages/pcaudio/119979/ "found that a function called memcpy was the culprit, most memory players use memcpy and this is one of the reasons why memory play sounds worse ie digital sounding. Fortunately there is an optimised version of memcpy from http://www.agner.org/optimize/ http://www.agner.org/optimize/, using this version removes the hard edge produced by memcpy."

wuntimer 4y ago
I don't know why people are mocking this discussion. It's well documented that tight loops on CPUs can cause electromagnetic interference. Old timers with C64s will recall how it could affect the TV monitor output "fuzziness" and nearby AM radios - heck, I could even tell how a program hung by the sound it made. https://news.ycombinator.com/item?id=16167594 https://news.ycombinator.com/item?id=16167594 https://retrocomputing.stackexchange.com/questions/25435/commodore-64-noises-during-loops-flash-load-and-others https://retrocomputing.stackexchange.com/questions/25435/com...
- YoshiRulz 4y ago
  Modern CPUs can produce an AM radio signal too https://github.com/fulldecent/system-bus-radio https://github.com/fulldecent/system-bus-radio
vaidhy 4y ago
Is the website a play on insane asylum for audiophiles?
- 77pt77 4y ago
  No. They really are like that!
  - JohnBooty 4y ago
    I mean, it depends on our definition of "they." Lots of audiophile communities (ones based around actual engineering) who laugh their asses off at this insane lunatic fringe stuff just like HN does.
benob 4y ago
It's probably that by optimizing code they reduced CPU load, therefore reducing fan noise due to overheating, and finally inducing clearer sound quality with lower SNR. It makes sense to me.
- mytailorisrich 4y ago
  Surely they'd run this on a system without a fan? I'd say immersed in liquid nitrogen to minimise thermal noise and powered through an ultra-low noise, DC, battery-only supply, and the whole thing inside an independently Earthed faraday cage. If not, all the effort on the memcpy is going to waste.
- JohnBooty 4y ago
  I'm not sure if that's what the (almost certainly delusional) linked article was talking about but your explanation holds water... but only for onboard motherboard embedded audio. That does tend to pick up a lot of electrical noise and just be mediocre at best. However this can all be sidestepped with an affordable external DAC connected with optical or USB.
  - IYasha 4y ago
    No it can't! I have a IEEE1394 pro-grade interface AND IT IS STILL BUZZING!! Everything is shielded. I even added ferrite rings onto the data cable.
    - JohnBooty 4y ago
      That sounds like some kind of ground loop problem, then, maybe? There are battery-powered USB DAC/amp combos, primarily designed for portable use. I think FiiO makes/made some. That should solve or at least isolate the problem further to some extent.
- scoutt 4y ago
  And what about the one thousand parallel memcpys happening while you listen to your non-memcpy audio program? Like in, is really one less memcpy doing all that difference?

wuntimer 4y ago

I don't know why people are mocking this discussion. It's well documented that tight loops on CPUs can cause electromagnetic interference. Old timers with C64s will recall how it could affect the TV monitor output "fuzziness" and nearby AM radios - heck, I could even tell how a program hung by the sound it made. https://news.ycombinator.com/item?id=16167594 https://news.ycombinator.com/item?id=16167594 https://retrocomputing.stackexchange.com/questions/25435/commodore-64-noises-during-loops-flash-load-and-others https://retrocomputing.stackexchange.com/questions/25435/com...

YoshiRulz 4y ago
Modern CPUs can produce an AM radio signal too https://github.com/fulldecent/system-bus-radio https://github.com/fulldecent/system-bus-radio

vaidhy 4y ago

Is the website a play on insane asylum for audiophiles?

77pt77 4y ago
No. They really are like that!
- JohnBooty 4y ago
  I mean, it depends on our definition of "they." Lots of audiophile communities (ones based around actual engineering) who laugh their asses off at this insane lunatic fringe stuff just like HN does.

benob 4y ago

It's probably that by optimizing code they reduced CPU load, therefore reducing fan noise due to overheating, and finally inducing clearer sound quality with lower SNR. It makes sense to me.

mytailorisrich 4y ago
Surely they'd run this on a system without a fan? I'd say immersed in liquid nitrogen to minimise thermal noise and powered through an ultra-low noise, DC, battery-only supply, and the whole thing inside an independently Earthed faraday cage. If not, all the effort on the memcpy is going to waste.
JohnBooty 4y ago
I'm not sure if that's what the (almost certainly delusional) linked article was talking about but your explanation holds water... but only for onboard motherboard embedded audio. That does tend to pick up a lot of electrical noise and just be mediocre at best. However this can all be sidestepped with an affordable external DAC connected with optical or USB.
- IYasha 4y ago
  No it can't! I have a IEEE1394 pro-grade interface AND IT IS STILL BUZZING!! Everything is shielded. I even added ferrite rings onto the data cable.
  - JohnBooty 4y ago
    That sounds like some kind of ground loop problem, then, maybe? There are battery-powered USB DAC/amp combos, primarily designed for portable use. I think FiiO makes/made some. That should solve or at least isolate the problem further to some extent.
scoutt 4y ago
And what about the one thousand parallel memcpys happening while you listen to your non-memcpy audio program? Like in, is really one less memcpy doing all that difference?