Hacker News Reader

Comment by ythn | Hacker News Reader

Sometimes I can "hear" my processor working through my headphones. I'm not sure how, but, for example, when I scroll down a page I can hear high frequency chirping in my headphones which stops as soon as I stop scrolling.

View on HN

It is caused by the increase/decrease in power consuption, as in general the audio chip isn't properly isolated from the power source of your computer. So, as more power is used (by slightly increasing the CPU speed, for example, to render the page as you scrooled it), the audio chip amplifies it.

It is a problem of some motherboards, and one way to get ride of it is to use another audio chip (for example, a small USB device that acts like a sound card).

The external USB sound card doesn’t always work because the USB supply voltage can vary with processor CPU. You need to use a USB headphone output with good isolation.

...which is still a "USB sound card", no matter how you choose to look at it. It still needs to be a combined DAC and headphone amplifier in addition to being a set of 'phones.

Personally, I use an Audioquest Dragonfly USB DAC/headphone amp, which gives me the option to use either headphones (of my choosing) or speakers. (And unlike a larger "breakout box" USB sound card, it's quite portable, being about the same size and shape as USB thumb drives used to be.) It's a good fit for me, but if you need mic input, there are other devices - or you can still use the mic in of your regular sound card/integrated audio.

I can also "hear" something when I scroll on some computers, but I hear them with my ears, no headphones required.

On one particular susceptible computer I did a bit of testing, and scrolling white background pages made the noise, but black background ones didn't! Scrolling a completely white page also made the noise. And it depended on app, some apps were immune, it seemed to only happen on GPU-accelerated apps, like browsers.

I used to be able to hear data going over the serial port back in the modem days. Some systems used to make a buzz when scrolling too. These days I have not heard that, but I'm not sure if it's because the frequencies have gone up (outside of my hearing range) or the parts have better isolation or I'm just going deaf as I get old.

I don't think I've heard scrolling noise since I stopped using analog video signals.

There are motherboards with higher quality components or isolation that eliminates this problem. The Pyra (open source mini gaming computer) recently solved their problem with the noise:

https://pyra-handheld.com/boards/threads/stop-the-sirring-no...

Likely it's your GPU or LCD panel leaking RF. Try turning your monitor off and see if scrolling is still audible.

These phenomena are more typically caused by ground loops and shield currents in the computer itself. Reordering plug-in cards (e.g. moving a sound card to a different slot) or isolating/removing the slot bracket can help.

That's generally caused by poor shielding between components, to save on cost.

Back when I was making electronic music, I noticed that I could hear pixels. When I did things that changed a region of the screen — pulling down a menu, switching windows, etc. — an audible whine would change on my audio monitors.

This was back in the CRT days, so I'm not sure if it's still an issue today, but it took me forever to figure out what was going on and drove me crazy when I noticed it.

I do find that generally USB headphones do better and minimizing interference/noise. Which makes sense, having a sound card on your motherboard is pretty much a worst case scenario. With USB it's not till outside the case that you are susceptible to RF.

What I remember finding most annoying was when you can hear the same (IIRC, actually the inverse) through your monitor.. as in it would whine ever so slightly unless you were scrolling. (NB no speakers involved)

I have noticed this on the front audio connectors, as the leads supplied with the case are not properly shielded but not on the rear, so that might be worth a shot before buying another sound card.

Reply on news.ycombinator.com