audio interference over line output dv9000

hi there,
I don't have a problem with machine noise from the Pavilion itself, but i get bad interference over the line output. The interference noise coming out of the speakers doesn't alter with volume changes on the Pavilion.. It is a buzzing type noise!
Any ideas?

Thanks very much for any help

 

Its more than likely your inbuilt microphone or CD player is on. to turn that off, go to control panel - classic view - sound and audio devices - and click the 'advanced' button.

There should be a slider bar called 'mic volume'. mute it. If you have a 'cd player' bar, mute that too. Also mute 'PC beep' if you have that.

If that dosen't help then...

With most notebooks, that sound is caused from the internal components. To verify this, plug in some headphones and listen carefully for any of that buzzing when your computer is first starting up. You shouldn't hear any sound at first, but as things in your laptop start to turn on, the sound should get louder. If this is the case, there isn't much you can do.

Alternatively, check to see if the sound changes (is louder, or intermittent) when your CD drive spins up. If it does, then again there isn't much you can do.

The sound is caused by interference ( Electro Magnetic Interference) from all your internal components, i.e. the hard drive, monitor, GPU, CPU, USB ports, CD drive, pretty much everything. You'll probably notice that the sound changes a bit when you scroll though this web page, minimize/maximize windows, etc.

The amount of noise your laptop's audio picks up depends on the route the audio signal takes through your computer. The longer the route, the closer to components it is, and the more power being used by the components, the louder the sound will be.

If the audio jack on your laptop were connected via a plastic sheathed wire, you could take some measures to protect it from EMI (using tin foil for instance, though you'd have to be very, very, very careful). However, it is far more likely that the signals travel through your motherboard.

Here are some long-shot solutions: You can try putting ONE layer of tin foil around your hard drive. HD's are a big contributor to EMI. Be EXTREMELY careful not to allow the foil to touch any metal contact points etc. You could short circuit your computer components and fry it.

Keep in mind that HD's emit EMI though their sides. The top and bottom emit no EMI at all. Heres a crappy diagram to illustrate my point: equal signs are the drive, brackets are EMI.

(((====)))

In other words, all you really need is a layer of tin foil on the sides of the drive.

Some laptops have a metal cage of sorts for their hard drives. If this is the case, then tin foil will do diddly squat.

You could also try a headphone amplifier, as it may filter some of the sound out, though I haven't heard any feedback on this solution. There are drawbacks with this too however. Since a headphone amp is powered, you have to be careful not to pull your headphones out while it's on, as doing so may cause damage to your headphones.

Also, try using programs like Daemon Tools and Alcohol 120% instead of your CD drive when possible; when the CD drive spins up a CD, it will most likely add to the noise (because its drawing a lot of power for its motor).

Let me know if any of this helps

 

many thanks for that, it was the cd player, followed your advice and it solved the problem.
Thanks again much appreciated