Hissing in speakers is generally due to noise in the system somewhere getting amplified. There will always be a certain amount of noise, but what you can do is check to be sure your input gain is set on the high side. That helps ensure there's maximum signal to the (sadly, generally fixed) amount of background noise. Then adjust overall volume from the master.
The other thing is to try and isolate the cause of the noise by switching around between various end sources. So - If the noise is tehre when the DVD player is on, but not when it's off, then you know it's either the player or the interconnects to/from the player. Same on a computer - Try to mute and unmute various sources.
Onboard audio is typically not high quality, it's possibly your problem, it's also possible you've got a component in your system that's injecting more noise than usual (maybe something that's close to failing... or that isn't intended for consumer use). I have Realtek onboard audio on my HTPC but I replaced it with an Audigy card a couple years back, using the optical output to my audio rack keeps everything digital in the PC where you're most likely to get noise.
Same thing happened to me. Tried numerous things and was ready to pull my hair out. I finally found the problem. I went into Realtek HD audio manager and then to Device advanced settings. Click on "Make front and rear panel output devices playback two different audio streams simultaneously" and uncheck the "Output mic in/line to front panel" and "Output mic in/line to rear panel" and the hissing should stop . Worked for me. I don't know how the settings changed in the first place but I had the same problem you described. And when I did as stated the hissing stopped immediately.
try muting your line in and any else that is not in use in the sound options
makes a big difference
I had to make an account just to thank you, I muted my rear mic input and it fixed the problem. Thanks so much.
yep, this works. I had a bad hissing sound, and i turned off the "listen to mic" option, and then it worked perfectly.
I had a little strange observation regarding this hissing sound in my pc, that is the sound is exactly matched to my HDD LED's Status. It is just acting like a disco light with respect to the hissing sound.
I reduced the playback volume of the mic in the Relatek Audio Manager. Then the problem is cleared off.. No More hissing sound. But if i increase the playback volume of my mic, the problem is still there.
May be Realtek guys should look in to this.... relation between harddisk and speaker hissing sound
You're probably hearing the EMI from your hard drive's read head moving around. Any sound board that does anything with analog is susceptible to interference like this. I get a lot of it from optical drives on systems with cheap sound hardware.
Some components are more susceptible to interference than others. Anything that's an analog input will react more strongly to interference than anything that's an analog output. (i.e. Aux, Line, Mic inputs.)
The most sensitive point of interference though, is the cheap onboard microphone booster that you have to turn on to get decent levels on your mic. The microphone signal is such tiny voltage, that baseline noise that Scotteq mentioned is much more significant in comparison. When the microphone booster amplifies that signal, the noise and the mic get amplified together, boosting the noise.
I used to have the Audigy 2 ZS Platinum and that breakout deck was great for that. The mic gain knob was a great quality mic input that I now miss. (But Creative have decided that the only customers who EVER use an audio input are musicians, and that musicians never play games...)