Doug said:
The only thing I added new was Windows updates. I started to have a
pretty loud crackling in my speakers. It does it when waking up
Computer, and at random times??
I uninstalled the updates, still have the problem.
If someone could help I would appreciate it.
Thanks
Doug
If you shut down Windows completely, then power up the computer later,
press the BIOS entry key (<del> or F2 or the like), and sit in the BIOS,
do you hear the crackling then ?
What I'm suggesting, is test whether this is a Windows related issue,
or a hardware related issue. By shutting down Windows, and not returning
from hibernation or standby, you can test whether the crackling happens
from a cold start. If it happens while you're sitting in a BIOS setup screen,
then you know it isn't Windows doing it.
You could also test the computer with an alternative OS, and see whether
there is crackling there or not.
You could also try a portable sound device (MP3 player), and connect
it to the external amplified computer speakers, and see whether that
same effect is present or not. That test is to see if the issue is with
your amplified speakers. Turn the amplified speakers on from "cold", and
see if the effect exists for the first couple minutes of usage.
There are hardware reasons possible for crackling, but they've changed
over the years. On older computers, there is "PCI Delayed Transaction",
which if not enabled, caused poor PCI bus transfer rates when the computer
is also accessing slow disk interfaces. Another setting was PCI Latency,
which limits the size of PCI bus transfers. The acid test for those
effects, was listening to the music played as the "welcome to Windows",
where there was a lot of disk activity, at the same time as the computer
was attempting to play sound. If the "welcome to Windows" played cleanly,
then chances are the sound would be good the rest of the time.
But at least the PCI Delayed Transaction setting has disappeared from the
BIOS, mainly because it is always enabled now. And PCI Latency tuning
is pretty well always set the same on systems now, and isn't the issue it
used to be.
On newer systems, it could be the response to Deferred Procedure Calls.
A tool called DPC_Latency_Checker could be used on other OSes, to check
how long it was taking for a Deferred Procedure to get serviced. In an
interrupt handler for hardware, such as a sound card, part of the
interrupt service can be done at interrupt level, and the rest can be
scheduled for later, as a Deferred Procedure Call. If the computer is
experiencing long delays to service such a DPC, that can cause the
sound system to run out of samples, buzz or crackle or whatever. This
tool provides a means to evaluate how crappy your motherboard is.
http://www.thesycon.de/deu/latency_check.shtml
Now, on Intel systems at least, there is a "feature" that allows the
BIOS to execute code on a regular basis. The feature is so clever,
it can interrupt the OS transparently, and the OS doesn't even know
it is happening (it has a very high priority, so can interrupt the
system when it wants to). The only observation you can make from the OS,
is there has been a "jump in time". So if you were timing a certain
event, every once in a while, it might take longer than normal.
http://en.wikipedia.org/wiki/System_Management_Mode
Well designed usage of SMM, involves microsecond length routines,
so that the impact on the computer is minimal. It's when such usage
stretches into the 10's of milliseconds, that rules are broken.
On some computers, the magnitude of delay seen with DPC Latency Checker,
was a function of the BIOS release (Gigabyte brand motherboards ?). Some
releases of the BIOS, were worse than others, for real time responsiveness,
and this is because of the background SMM activity.
So there are some hardware reasons things like this can happen. A software
change, could change the dynamics of the situation, but as far as I know,
in the end, hardware is the thing falling down and making the crackling,
buzzing, or popping sound. Perhaps it's something an AV tool is doing or
the like.
I've even had a Soundmax built-in sound solution on a motherboard, where
the damn thing would let out a single "pop" once every ten minutes. For
that one, the frequency of popping was reduced, with each new driver release.
It seemed to be something like a slipped sound sample, as if two things
weren't running at the same frequency, and eventually a sound sample would
have to be added or discarded, to adapt sampling rates. But I couldn't
really find anything to fix it, or any suggestion that anyone else had
an idea as to what was busted. The solution there, was a $7 sound card,
as it's easier to just replace the sound chip, then find a fix. Only a
small number of sound defects, can be fixed by changing sound cards.
For the software to flat out, make its own "crackling" sound, isn't very
likely. But if some software has changed the way hardware resources
are used on your system, that could contribute to the hardware doing
the crackling, when some real time constraint isn't being met. The sound
chip can only wait so long, for servicing, before it has an impact on
sound sample input or output.
Paul
