[Trac #1025] display noise at mid brightness
Zarro Boogs per Child
bugtracker at laptop.org
Wed Mar 14 04:11:17 EDT 2007
#1025: display noise at mid brightness
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Reporter: AlbertCahalan | Owner: mlj
Type: defect | Status: new
Priority: low | Milestone: Untriaged
Component: hardware | Resolution:
Keywords: |
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Comment (by gnu):
My B2 also makes a noise -- I was surprised to hear it, but when I put my
ear up to the left and right bezels, I can clearly hear a buzzing. In a
no-moving-parts unit, I thought this would be unusual. But it turns out
that there is a part that's designed to move -- the '''speakers'''. When
the volume control is not off, they amplify electronic noise from within
the unit. Changing the volume level using the keyboard buttons makes it
clear where the noise (in my machine) is coming from.
Others have reported noise when OFW scrolls the screen. I haven't tried
that and also haven't tried changing the volume from OFW and seeing if it
changes the amplification of the noise. Making the CPU and/or the screen
active could easily change the pitch and volume of the digital noise
that's being amplified here.
Better shielding of the analog audio section before the amp -- or some
kind of analog squelch circuit that won't light up the speakers unless the
signal is above a certain level -- might fix it. Or it could be largely
fixed in software: when nothing is playing through the audio subsystem,
the amp volume could be set to zero (and restored to its proper value upon
opening the device).
--
Ticket URL: <http://dev.laptop.org/ticket/1025#comment:1>
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