this posting has several sections: 1) PROBLEM, 2) TRIED, 3) SYSTEM,
4) QUESTIONS
PROBLEM:
Loud hum/feedback from mic just started. No apparent reason for it to
start.
Went to use Skype (as normal, several times a week) and as soon as I
turned the mic on with the little built into the mic/headset line,
slide switch the HUMMMMMMMM came immediately…Loud!
Turned down speaker, then checked Kmix which was, as best as I can
tell about what it had been for months (mic close to max and Mic
Boost (+20dB) on) which had consistently received reports from around
the world as “loud and clear”, sometimes “like next door”)…
hum responds as expected to changes in Kmix, up/down with volume
controls, boost on/off, or mic LEDs clicked off/on
TRIED:
used “Skype Test Call”
– results: in audio play back could hear myself but BARELY and in
a garbled hum
searched forum for thread subjects with hum and/or feedback
–results: none found
search forum for thread subjects with mic*
–results: found LOTs and learned a lot about the mic NOT WORKING at
all, but nothing about feedback/hum from the microphone
unplugged headset from the computer front–plugged in the back
–results: no change, hum/feedback the same
tried a different mic
–results: no change, hum/feedback the same
noticed that hum changes (gets louder) when i pick up the headset,
AND decreases in volume if i touch metal (ground) inside the computer
case…
untangled the leads of the desktop speakers, shortened them and
rerouted so they don’t run along side power cords (this sounds like a
typical 50/60 hertz power line induced hum which sometimes comes in
(say) hi-fi or amateur radio from improper grounding)
– results: no change, hum/feedback the same
reversed power cord for desktop speaker system (this often solved
power cord induced hum between the Fender amp and Shure mic in the
old rock band)
– results: no change, hum/feedback the same
tried to collect information for the gurus here:
–result: wget http://home.cfl.rr.com/infofiles/tsalsa && su -c
‘bash ./tsalsa’ no longer works
–result: /usr/bin/alsa-info.sh (as root, su -) No such file or
directory
SYSTEM:
Desktop, AMD, SUSE 10.3, KDE 3.5.x (more?)
motherboard: ASRock K8Upgrade-760GX <www.asrock.com>
audio: (on board) CMedia 9761 6channel AC’97 audio codec
I wonder if a recent “openSUSE Updater” action killed my mic, or
something else (hardware)?
I’ve read about other things grabbing the sound system and not
letting go. I know that sometimes i have to reboot to recover sound
after MPlayer has had its way–but, this hum has persisted through
several days of reboots and fiddling with Kmix and YaST sound “knobs
and switches”. So how might i clear possible conflicts with Flash
player, MPlayer, Kaffeine, Totem, VLC media player, Amarok, or Banshee?
Try reversing the power cord for the desktop computer itself. I’ve seen this help in cases.
wrong directory.
alsa-1.0.17 or newer users should try:
/usr/sbin/alsa-info.shas user root. Run it twice. 1st time to update the script. Second time to get the URL it provides.
Note that alsa-info.sh comes with 1.0.17 of alsa on openSUSE-11.1 and not 11.0 nor earlier openSUSE versions. Hence as an openSUSE-11.0 user, even if you specified the correct directory, it would not work if run that way with your 1.0.14 of alsa.
Instead (assuming you have “wget” installed) copy and paste the following into a gnome-terminal or kde konsole (with your PC connected to the internet):
Thanks. Your mixer settings are there, and its possible you still need to tune your mixer. ie. backoff on the capture levels, and increase the volume playback levels.
Before I make suggests (based on your mixer levels from the script), please confirm your mic works, but that the quality is poor.
> Thanks. Your mixer settings are there, and its possible you still need
> to tune your mixer. ie. backoff on the capture levels, and increase the
> volume playback levels.
since your last post i tried turning the capture halfway down,
three-quarters down and WAY down, then by the time i get the playback
level high enough to hear anything, the mic hum still nearly
drowns out the message (using Skype test)…and what of my voice i
can hear (not much) is weak and garbled in the noise…
> Before I make suggests (based on your mixer levels from the script),
> please confirm your mic works, but that the quality is poor.
i’ve tried two different mics (not usb), both into the front AND back
panel connection…
remember: this “just started” on 10.3 on or about 15 Feb 09 (when it
was first encountered) which had been in use for over a year giving
high quality, two way comm via Skype to world wide contacts (with
both mics, which now produce so much hum as to be unusable)…
since i HAVE fiddled with the mixer levels and the speaker (and
headset) volume knobs–should i run another script for you ??
You could try updating your alsa, but there are no guarantees that will work. I note your pc is using the “intel8x0” and there have been various updates to that since 1.0.14 of alsa.
To update your openSUSE-10.3 (which has the 2.6.22.19-0.2 kernel) to the latest alsa version, open a gnome terminal or kde konsole, with your PC connected to the internet, and type ‘su’ (no quotes - enter root password) to get root permissions and then copy and paste and execute the following commands, one at a time in sequence:
zypper ar http://download.opensuse.org/repositories/multimedia:/audio/openSUSE_10.3/ multimedia
/multimedia:/audio:/KMP/openSUSE_10.3_Update/ multimedia
Too many arguments.
Usage:
addrepo (ar) [options] <URI> <alias>
Add repository specified by URI to the system and assing the
specified alias to it.
Command options:
-r, --repo <FILE.repo> Read the URL and alias from a file (even remote)
-t, --type <TYPE> Type of repository (yast2, rpm-md, or plaindir)
-d, --disabled Add the repository as disabled
-n, --no-refresh Add the repository with auto-refresh disabled
---------------end quote---------------------------------
and, i can’t figure out what i should do to fix it…
help!
> hmmmmmm…all was going perfectly until the following:
>
>> Code:
>> --------------------
>> zypper ar http://download.opensuse.org/repositories /multimedia:/audio:/KMP/openSUSE_10.3_Update/ multimedia
>> --------------------
>
> which returned this error:
>
> ---------------quote---------------------------------
> <snip>
> ---------------end quote---------------------------------
>
> and, i can’t figure out what i should do to fix it…
WAIT, i figured it out…there is an unneeeded space between
repositories and /multimedia, here:
org/repositories /multimedia
^
i removed that and it ran fine…
then, followed the other advice and, restarted, checked my mixer
closely and found no change whatsoever…
fiddled with mixer controls all i could and never go away from the
hum as before…
since the volume level of the hum immediately pops way up when i pick
up the headset AND then drops WAY down when i touch the metal chassis
(ground) i suspect a ground feedback loop…possibly recently caused
by a new hardware problem…dang it.
Hardware. Software is not sensitive to these actions
Hardware? oldcpu was in the right area [but obviously the wrong continent] when he suggested reversing the power cord. The relevant part is to take a look for broken earth connections on the power side of things.
But you could go further and look for similar on the audio side. Earth side hum loops tend to be stable unless you actually change the geometry of a loop, which your actions reported above should not do. So I would be looking for broken connections - try complete substitution of heeadphones, microphones and external kit - then look at removing new hardware.
> try complete substitution of
> heeadphones, microphones and external kit - then look at removing new
> hardware.
since i have no “new hardware” involved…AND i’ve already
substituted two different headphone/microphone sets (which both
worked perfectly for a couple of years, and suddenly stopped, last
sunday), and have exactly the same results with both…i zero in on
“external kit”…
unpluged the external speakers from the back, and get (damn) get
exactly the same hum (also diminished when i touch ground)…
and, when recording to Skype Test Call without touching ground it is
unintelligible and garbled, but when touching case ground it is weak
but readable…
ooooh: the second headset had a little less hum, AND when touching
ground it gave an almost “loud and clear” recording…
BUT, totally new is i can turn off the 20 dB mic boost AND turn the
mic input down to around 10% and STILL record (to Skype)…hmmmm, it
has never been THAT way before…
and, that is happening with both headsets…
i’m beginning to guess my on motherboard sound circuits are
undergoing changes…
i think tomorrow, in the sunlight i’ll take a close look at the
motherboard…and, then i’ll find a sound card and give that a
whirl…and get back to you fine folks…