[ltp] noise in audio on T430s

Richard Neill linux-thinkpad@linux-thinkpad.org
Thu, 26 Sep 2013 13:37:49 +0100


Dear Tamas,

>
> I am not an audiophile, but recently got Bose QC 15 noise-cancelling
> headphones (for working on trains/airplanes).  They are so good that now
> I notice the electical noise of the machine itself, since I play the
> actual music on very low volume.
>
> I was wondering it would be possible to reduce this.  Opening up the
> mixer and trying various settings, I did notice the muting "Speaker" in
> "Intel Pantherpoint HDMI (OSS mixer)" gets rid of a lot of noise.  I
> wonder if there is anything else I can try.

I've noticed this too. Turning off all the unwanted mixes helps a bit. 
Then, turn up your signal as much as you can (in the application and the 
thinkpad's mixers), and attenuate by lowering the volume in the 
headphones. (that will keep the volume constant and improve the 
signal-noise).

After this, you need to go for USB-audio, or perhaps bluetooth. My 
experience is that very cheap (5 on eBay) USB devices are dreadful, but 
I've personally had great results with the Behringer devices, such as 
the UCA202 (22 on Amazon): in fact I use this with my desktop PC and hi-fi.

Lastly, what kind of noise do you get? Is it hum, hiss, or interference? 
The noise-cancelling headphones can also add a very high-pitched, quiet, 
squeak (sounds like an analog TV flyback coil) sometimes.

Best wishes,

Richard