loud static noise when using headphones?!?

[rvlmtfnk]

i have a T43 that was purchased in december last year. it's the one with the fingerprint recognition. anyway, when using my headphones plugged into the laptop headphone jack, there's a rather annoying static noise that's reasonably loud (i can hear it even when playing my music). however, it goes away when i touch the fingerprint reader or any other part of the laptop with exposed metal (i.e. usb ports, modem jack, etc..)

is there anyway to solve this permanently? thanks.

if it's any help, the headphones are Bose QuietComfort 1's...

[alexzabr]

Does it occur in both cases when running from main power or battery ? If this is only when main power is supplying the machine - it may be caused by main power hum at frequency of 60Hz (if you're in US for instance), but I'll be wondering why it isn't filtered out properly as it should to be.
The fact that touching any exposed part will calm the noise down hints that there might be issues woth proper grounding - when touching exposed metal parts by your body you provide the grounding path to the charge so the noise is filtered out this way.

Alex

[sugo]

Um, I never get any static crack/pop/noise from headphone jack of T42. I don't think T43 uses Azalia either.

[sugo]

if it's any help, the headphones are Bose QuietComfort 1's...

Wait, that helps! The noise cancellation circuit in Bose QuietComfort adds static background noise. It's better in BQ 2 but it's still there.

Try a different headphone. The noise will probably go away.

[GomJabbar]

if it's any help, the headphones are Bose QuietComfort 1's...

Wait, that helps! The noise cancellation circuit in Bose QuietComfort adds static background noise.

Hey, that's slick! Cancel noise with noise! [not]

[christopher_wolf]

Hey, that's slick! Cancel noise with noise! [not]

Well, they do; but there *should not* be static that is audible in a quiet room coming from the headphones.

They simply take a good sampling of the background ambient noise levels, then use a set of feeback systems, 3 feedback systems most of the time, and phase shift the noise to cancel it out as the basic design. Although that can cause problems ( e.g. excessive phase shift caused by where the microphone is placed versus the relation of the noise to it and the headphone can cause problems; this is why open-auditorium NC systems are very difficult to design), so most systems now imploy seperated passive/active elements, a dedicated error processor to account for even the tiniest controller plant uncertainty (H-Infinity, Internal Model, Quantitative Feedback, Dynamic Time Delay, etc).