Doug Laidlaw wrote:
> I am running a Gigabyte motherboard with Mandriva 2008.1 and KDE. Using the
> onboard AC97 for sound. and external powered speakers.
>
> Sounds are audible in the speakers at low level which sound almost like
> instability, but which vary with hard disk activity. Muting the sound with
> Kmix stops the noise.
>
> Can I block these sounds with suppressors, or similar? I don't have any
> ferrite suppressors handy at the moment.

I have the same problem with one of my laptops, but not the other. I
don't have that trouble with any of the desktop machines I use. The
laptop that has the trouble doesn't have Windows on it, or I'd see if it
was operating system specific.

I guess I'm not help, other than to say, "me too."

Sorry....

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PLEASE post a SUMMARY of the answer(s) to your question(s)!
Show Windows & Gates to the exit door.
Unless otherwise noted, the statements herein reflect my personal
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Doug Laidlaw wrote:

> I am running a Gigabyte motherboard with Mandriva 2008.1 and KDE. Using
> the onboard AC97 for sound. and external powered speakers.
>
> Sounds are audible in the speakers at low level which sound almost like
> instability, but which vary with hard disk activity.

Can you redefine "which sound like instability"?

> Muting the sound with Kmix stops the noise.

Just a wild guess, not from an IT perspective but from my experience as a
musician... It is possible that either your speakers or - more likely -
your soundchip is experiencing microphonics. Concretely, this would boil
down to your soundchip picking up the vibrations from your hard disk
activity and amplifying them.

I myself am mainly an electric guitarist. Real electric guitars make use of
electromagnetic induction pickups - basically composed of one or two
bobbins with coil wire, with a magnet inside the bobbin - and can therefore
only be used with magnetically conductive strings, which pass through the
top of the pickup's magnetic field - we call this the magnetic window.

You pluck the string, it starts vibrating in the magnetic field and thus
disrupts the field, and this causes a signal to be generated in the coil
wire of the bobbins. As such, electric guitar pickups are not microphones,
because they can (in theory) only pick up the vibration of a magnetically
susceptible alloy string in their magnetic window.

However, on older electric guitars, poorly shielded and loosely assembled
pickups tend to be microphonic and pick up other sounds as well, such as
tapping on the guitar's wood or pickguard - this is especially true when
the pickups are mounted to the pickguard (like on a Fender Stratocaster)
instead of directly into the wood (with our without a metal or plastic
mounting ring) as more common with e.g. Gibson, Ibanez, Jackson, et al.

The microphonic effect is caused by the same principle through which
piezo-electric pickups on electric-acoustic guitars work and can be
eliminated by assembling the pickups more firmly, potting them in wax
and/or mounting them to the guitar body directly instead of to the
scratchplate.

My guess is that your soundcard is acting like a piezo-electric pickup,
which may not be the fault of the chip itself, but rather of the
motherboard design.

There are also other factors that could create disturbing sounds, such as
the EM interference from a rheostat. This is why Gibson invented the
humbucking pickup in the mid 1950s. Basically and simplified, a humbucker
pickup consists of two coils, mounted above a single magnet but on opposite
magnetic poles. These poles are extended to run through the center of the
bobbins via (usually iron) polepieces to extend the magnetic field so that
the strings pass through it.

Both coils are connected in series and 180° out of phase with one another.
The phase reversal and series connection then eliminates the humming, but
it would normally also eliminate the actual guitar sound, if it wasn't for
the fact that having both coils on opposite sides of the magnet's polarity
also generates a 180° phase reversal, which brings the actual electric
guitar sound of each coil back in phase with eachother. Humbucking pickups
do sound "fatter" than single coil pickups because of the series connection
- a sound that's quite beautiful and warm in its own right, though - but at
least the hum is canceled.

> Can I block these sounds with suppressors, or similar? I don't have any
> ferrite suppressors handy at the moment.

I think it would be best to make sure your hard disk's vibrations are muted
sufficiently. There are several mounting brackets and kits available to
this end, but I have no experience with them myself, and one must of course
also keep their possible negative effect on heat dissipation into
account... :-/

As for the motherboard... There's little you can do about that.
Motherboards are manufactured to form factor standards which also designate
the holes for the screws by which you attach the motherboard to the
chassis, and so my guess is that your motherboard has its sound chip
located in a less fortunate place where the board is susceptible to
mechanical vibrations inside the chassis. :-/

Anyway, just my two cents again... :-/

--
*Aragorn*
(registered GNU/Linux user #223157)

Doug Laidlaw writes:

> I am running a Gigabyte motherboard with Mandriva 2008.1 and KDE. Using the
> onboard AC97 for sound. and external powered speakers.
>
> Sounds are audible in the speakers at low level which sound almost like
> instability, but which vary with hard disk activity. Muting the sound with
> Kmix stops the noise.
>
> Can I block these sounds with suppressors, or similar? I don't have any
> ferrite suppressors handy at the moment.

Audio interference from nearby chips is quite common. Using a digital
(optical or coax) output should get rid of the noise.

--
Måns Rullgård
mans@mansr.com

In article ,
Måns Rullgård wrote:
> Doug Laidlaw writes:
>
> > I am running a Gigabyte motherboard with Mandriva 2008.1 and KDE. Using the
> > onboard AC97 for sound. and external powered speakers.
> >
> > Sounds are audible in the speakers at low level which sound almost like
> > instability, but which vary with hard disk activity. Muting the sound with
> > Kmix stops the noise.
> >
> > Can I block these sounds with suppressors, or similar? I don't have any
> > ferrite suppressors handy at the moment.
>
> Audio interference from nearby chips is quite common. Using a digital
> (optical or coax) output should get rid of the noise.

Such an option is often not available. AIR, what solved the problem for
me (or worked around it, one) was hdparm -u "get/set unmaskirq flag
(0/1)". But it's been years so ICBW. There might be /etc/hdparm.conf
in your distro but its structure is left as an exercise for the reader.

--
-eben QebWenE01R@vTerYizUonI.nOetP http://royalty.mine.nu:81
AQUARIUS: There's travel in your future when your tongue freezes to the
back of a speeding bus. Fill the void in your pathetic life by playing
Whack-a-Mole 17 hours a day. -- Weird Al, _Your Horoscope for Today_

Hactar wrote:

> In article ,
> Måns Rullgård wrote:
>> Doug Laidlaw writes:
>>
>> > I am running a Gigabyte motherboard with Mandriva 2008.1 and KDE.
>> > Using the onboard AC97 for sound. and external powered speakers.
>> >
>> > Sounds are audible in the speakers at low level which sound almost like
>> > instability, but which vary with hard disk activity. Muting the sound
>> > with Kmix stops the noise.
>> >
>> > Can I block these sounds with suppressors, or similar? I don't have
>> > any ferrite suppressors handy at the moment.
>>
>> Audio interference from nearby chips is quite common. Using a digital
>> (optical or coax) output should get rid of the noise.
>
> Such an option is often not available. AIR, what solved the problem for
> me (or worked around it, one) was hdparm -u "get/set unmaskirq flag
> (0/1)". But it's been years so ICBW. There might be /etc/hdparm.conf
> in your distro but its structure is left as an exercise for the reader.
>
Thanks all round. It sounds as though a separate sound card may be the
answer.

Doug.

On Wed, 14 May 2008 17:59:48 +1000, Doug Laidlaw wrote:

> I am running a Gigabyte motherboard with Mandriva 2008.1 and KDE. Using
> the onboard AC97 for sound. and external powered speakers.
>
> Sounds are audible in the speakers at low level which sound almost like
> instability, but which vary with hard disk activity. Muting the sound
> with Kmix stops the noise.
>
> Can I block these sounds with suppressors, or similar? I don't have
> any ferrite suppressors handy at the moment.
>
> Doug.

I had the same problem once. But it was the video that screwed up my
sound. As the screen changed, the hum would also change. I discovered
on opening my box that when I moved my sound card over one slot away from
the video card, the sound stopped. So maybe you should open up your box
and see if any wires from your hard-drive are close to the sound card.

stonerfish

Aragorn wrote:
> Just a wild guess, not from an IT perspective but from my
> experience as a musician... It is possible that either your
> speakers or - more likely - your soundchip is experiencing
> microphonics. Concretely, this would boil down to your
> soundchip picking up the vibrations from your hard disk
> activity and amplifying them.
>
> I myself am mainly an electric guitarist. Real electric
> guitars make use of electromagnetic induction pickups -
> basically composed of one or two bobbins with coil wire, with a
> magnet inside the bobbin - and can therefore only be used with
> magnetically conductive strings, which pass through the top of
> the pickup's magnetic field - we call this the magnetic window.
>
> You pluck the string, it starts vibrating in the magnetic
> field and thus disrupts the field, and this causes a signal
> to be generated in the coil wire of the bobbins. As such,
> electric guitar pickups are not microphones, because they
> can (in theory) only pick up the vibration of a magnetically
> susceptible alloy string in their magnetic window.

Hiya,

Your description of the coil/pickup stuff seems pretty good.
But, it's quite unlikely that there is magnetic interference
affecting the internals of the sound chip itself. I speak as
a designer of chips. Also, there are regulations as to how
much electromagnetic interference is tolerable to be put out by
electronic equipment. It's *much* more likely that the disk
drive is demanding different amounts of power from the power
supply and that this is causing the power supply voltage to
rattle a little, which could be picked up by the circuitry on
the soundcard. It's still possible that the gain on an unused
channel is turned way up, and that the channel is picking up
electric field interference from whatever is running inside the
case of the computer. But, I think magnetic field interference
is pretty unlikely.

Cheers....


--
PLEASE post a SUMMARY of the answer(s) to your question(s)!
Show Windows & Gates to the exit door.
Unless otherwise noted, the statements herein reflect my personal
opinions and not those of any organization with which I may be affiliated.

Doug Laidlaw writes:

< I am running a Gigabyte motherboard with Mandriva 2008.1 and KDE. Using the
< onboard AC97 for sound. and external powered speakers.
>
< Sounds are audible in the speakers at low level which sound almost like
< instability, but which vary with hard disk activity. Muting the sound with
< Kmix stops the noise.
>
< Can I block these sounds with suppressors, or similar? I don't have any
< ferrite suppressors handy at the moment.
>
< Doug.


Check your mic inputs and plug them with a 6-32 stainless steal screw and 30
feet of enameled copper 30awg hooked up to a nine volt.

Just kidding. They do sell dead plugs and I would recommend one of them, but
some people like the feedback.

`hdparm -M' will allow you to adjust the acoustic settings of a `ide' hard
drive if the drive allows it. It is actually recommended for certain drives.
Also slowing down the CPU cycles if an option in your bios may help. If you
can slow down your disk drive - some will some won't.

I placed two sata drives on a cardboard box while makeing a quick backup
through vista and they made some loud ass noise. I thought I was tapping
morse code with a hammer (I suffer from paranoia).

Cardboard usually works. Place in between video card and rest of pci bus. It
gets hot so be careful. Removing excess fans and grounding the power
supply/chassis might work. Be careful removing fans from the CPU! If you got
that funky paste it may start ok, but I dunno how well your machine reacts
to overheating. It should shut down immediately.

Place the computer on cardboard.

Use cardboard for mounting the drives externally.

I actually chased out a funky sound with a variable speed fan several times.
I think that the excess noise was result of heat build up in the case. The
pc speaker may have added some feedback do to thermo-reactions. The fan may
have cooled her off a bit or just smoothed the current. Dunno. Plugging one
in while the machine was on worked. Mystery fan method #1.

I am not a professional. I just make lots of mistakes. Staying clear of the
ac line can help too and making sure you have air flowing from the power
supply with plenty of space. May mean dusting.