Re: [vox-tech] high-pitch noise when trying to raise the volume

[Peter Jay Salzman]

heh.  thanks for the compliment.  :)   but i think any electric engineer,
public speaker, or even someone who listens to a lot of rock music would be
able to identify "unbearable high-pitch noise when I raise the volume".
that's feedback.  it's unmistakable, and you did a good job describing it.

it's what you get when you take the output signal and feed it back into the
input.  in your case, the speaker output was being input into the
microphone, which was being pushed back through the speaker, which was being
picked up into the microphone, which was pushed back through the speaker,
etc...   :)

one way to deal with that is to turn off the input, meaning, either turning
the mic off (disconnecting the microphone) or turning the mic level down.

pete




On Sun 23 Jul 06,  1:51 AM, Hai Yi <[EMAIL PROTECTED]> said:
> pete, you are really good! I turned mic all the way down and the
> problem is gone! Do you mind eleborating on it a little more?
> 
> Thanks again,
> Hai
> 
> 
> On 7/23/06, Peter Jay Salzman <[EMAIL PROTECTED]> wrote:
> >On Sun 23 Jul 06,  1:28 AM, Hai Yi <[EMAIL PROTECTED]> said:
> >> hello,
> >>
> >> I have a problem with adjusting the volume when I watch the movie or
> >> listen to the music: the sound becomes unbearable high-pitch noise
> >> when I raise the volume (using alsamixer or other).
> >>
> >> I hope I could be able to provide more details, however, there is not
> >> too much info about it.
> >>
> >> Anyone experience this kind of problem?
> >>
> >> Thanks a lot,
> >> Hai
> >
> >Hmmm... Sounds like you might be hearing feedback.  Do you have a 
> >microphone
> >hooked up to your soundcard?  If so, disconnect it.
> >
> >Also, use whatever mixing software you use to mute the input.  For example,
> >with "xmix" (am I showing my age?) turn "mic" down all the way.
> >
> >Pete

-- 
The mathematics of physics has become ever more abstract, rather than more
complicated.   The mind of God appears to be abstract but not complicated.
He also appears to like group theory.  ---  Tony Zee's  "Fearful Symmetry"

email: [EMAIL PROTECTED]  web: http://www.dirac.org/p
PGP Fingerprint: B9F1 6CF3 47C4 7CD8 D33E  70A9 A3B9 1945 67EA 951D
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Re: [vox-tech] high-pitch noise when trying to raise the volume

[Hai Yi]

pete, you are really good! I turned mic all the way down and the
problem is gone! Do you mind eleborating on it a little more?

Thanks again,
Hai


On 7/23/06, Peter Jay Salzman <[EMAIL PROTECTED]> wrote:

On Sun 23 Jul 06,  1:28 AM, Hai Yi <[EMAIL PROTECTED]> said:
> hello,
>
> I have a problem with adjusting the volume when I watch the movie or
> listen to the music: the sound becomes unbearable high-pitch noise
> when I raise the volume (using alsamixer or other).
>
> I hope I could be able to provide more details, however, there is not
> too much info about it.
>
> Anyone experience this kind of problem?
>
> Thanks a lot,
> Hai

Hmmm... Sounds like you might be hearing feedback.  Do you have a microphone
hooked up to your soundcard?  If so, disconnect it.

Also, use whatever mixing software you use to mute the input.  For example,
with "xmix" (am I showing my age?) turn "mic" down all the way.

Pete

--
The mathematics of physics has become ever more abstract, rather than more
complicated.   The mind of God appears to be abstract but not complicated.
He also appears to like group theory.  ---  Tony Zee's  "Fearful Symmetry"

email: [EMAIL PROTECTED]  web: http://www.dirac.org/p
PGP Fingerprint: B9F1 6CF3 47C4 7CD8 D33E  70A9 A3B9 1945 67EA 951D
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Re: [vox-tech] high-pitch noise when trying to raise the volume

[Peter Jay Salzman]

On Sun 23 Jul 06,  1:28 AM, Hai Yi <[EMAIL PROTECTED]> said:
> hello,
> 
> I have a problem with adjusting the volume when I watch the movie or
> listen to the music: the sound becomes unbearable high-pitch noise
> when I raise the volume (using alsamixer or other).
> 
> I hope I could be able to provide more details, however, there is not
> too much info about it.
> 
> Anyone experience this kind of problem?
> 
> Thanks a lot,
> Hai

Hmmm... Sounds like you might be hearing feedback.  Do you have a microphone
hooked up to your soundcard?  If so, disconnect it.

Also, use whatever mixing software you use to mute the input.  For example,
with "xmix" (am I showing my age?) turn "mic" down all the way.

Pete

-- 
The mathematics of physics has become ever more abstract, rather than more
complicated.   The mind of God appears to be abstract but not complicated.
He also appears to like group theory.  ---  Tony Zee's  "Fearful Symmetry"

email: [EMAIL PROTECTED]  web: http://www.dirac.org/p
PGP Fingerprint: B9F1 6CF3 47C4 7CD8 D33E  70A9 A3B9 1945 67EA 951D
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[vox-tech] high-pitch noise when trying to raise the volume

[Hai Yi]

hello,

I have a problem with adjusting the volume when I watch the movie or
listen to the music: the sound becomes unbearable high-pitch noise
when I raise the volume (using alsamixer or other).

I hope I could be able to provide more details, however, there is not
too much info about it.

Anyone experience this kind of problem?

Thanks a lot,
Hai
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Re: [vox-tech] CD Burner Recomendation?

[Richard Harke]

On Sat July 22 2006 13:39, Bob Scofield wrote:
> I need a new CD burner.  In the past a lot of folks have recommended
> Plextor for Linux.  That's what I have now.  Do people still think Plextor
> is a good recommendation for a Linux machine?
>
The last burner I bought was a $40.  unit from Frys that does CD's, DVD's, 
including double desity. I have recorded CD's using cdrecord and DVD's
using growisofs. The documentation with it is essentially non-existant.
I have never had occasion to try double density but I'm happy with the
rest. While it is a no-name knock off, its was hard to resist the
low price. (Well, actually, I think is was labeled Emprex on the box)

Richard harke
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[vox-tech] CD Burner Recomendation?

[Bob Scofield]

I need a new CD burner.  In the past a lot of folks have recommended Plextor 
for Linux.  That's what I have now.  Do people still think Plextor is a good 
recommendation for a Linux machine?

Thank you.

Bob
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Re: [vox-tech] SSH Troubles

[Marc Elliot Hall]

On Sat, Jul 22, 2006 at 06:37:46AM -0700, Ken Herron wrote:
> Marc Elliot Hall wrote:
> >On Fri, Jul 21, 2006 at 08:50:46AM -0700, Ken Herron wrote:
> >  
> >>Ken Herron wrote:
> >>Okay, see , 
> >>in particular "Why PORT Poses Problems for Routing Devices" and 
> >>"Problems when the FTP Server is Listening on a Non-Standard Port 
> >>Number". Now imagine your netgear thinks it's dealing with FTP and is 
> >>doing that to your ssh sessions.
> >>
> >Not that I'm disagreeing with you about the router's possible confusion,
> >but I'm not running an FTP server. ;-)
> 
> I never said you were. You're running ssh over port 21, which is 
> normally the ftp command channel port. So the router might be applying 
> its ftp forwarding support to your ssh traffic and scrambling it in the 
> process.
> 
> >I'll investigate further in this direction; however I don't think my 
> >appliance is nearly smart enough to rewrite packet headers. It just 
> >accepts inbound traffic on designated ports and passes it through 
> >unmodified to the same port on a specified host on my network. 
> 
> Netgear routers can  port-forward ftp. If you'd read the link above, 
> you'll see that dumb packet forwarding isn't sufficient to port-forward 
> ftp. So netgear routers almost certainly have logic to do the protocol 
> monitoring and packet rewriting described.

Thank you for the additional comments, Ken. I have read the link you
referenced, and agree that there is a possible relationship between the 
issue I'm experiencing and the Netgear WGT624's firmware thinking that 
if an incoming packet is hitting port 21, it must therefore be FTP -
not that that would be "normal" given my last 18-odd months of
successful ssh-ing with the same config. 

However, I have concluded that this broken behavior is indicative of a
hardware failure (Cosmic rays? Overheating? Whatever...), because 
while tinkering with various PuTTY settings while troubleshooting 
(frex, enabling and disabling single-DES in SSH-2, deleting the saved 
rsa key, etc.), I got this PuTTY Fatal Error:

++
Server sent disconnect message" 
type 2 (SSH_DISCONNECT_PROTOCOL_ERROR)
Corrupted MAC on input
++

and that led me here:

http://www.derkeiler.com/Newsgroups/comp.security.ssh/2005-03/0113.html

I'm going to attempt to update the firmware to 4.2.11; but if that
doesn't fix things, I'll have to get me a new device (OpenWrt doesn't
have a Free replacement available yet).


-- 
Marc Elliot Hall
www.hallmarc.net
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Re: [vox-tech] SSH Troubles

[Ken Herron]

Marc Elliot Hall wrote:

On Fri, Jul 21, 2006 at 08:50:46AM -0700, Ken Herron wrote:
  

Ken Herron wrote:

Also, I've read that to port-forward an FTP server, the firewall has 
to watch the FTP command channel, open holes for each data connection, 
and maybe even modify some packets.
  
Okay, see , 
in particular "Why PORT Poses Problems for Routing Devices" and 
"Problems when the FTP Server is Listening on a Non-Standard Port 
Number". Now imagine your netgear thinks it's dealing with FTP and is 
doing that to your ssh sessions.




Not that I'm disagreeing with you about the router's possible confusion,
but I'm not running an FTP server. ;-)
  


I never said you were. You're running ssh over port 21, which is 
normally the ftp command channel port. So the router might be applying 
its ftp forwarding support to your ssh traffic and scrambling it in the 
process.


I'll investigate further in this direction; however I don't think my 
appliance is nearly smart enough to rewrite packet headers. It just 
accepts inbound traffic on designated ports and passes it through 
unmodified to the same port on a specified host on my network. 
  


Netgear routers can  port-forward ftp. If you'd read the link above, 
you'll see that dumb packet forwarding isn't sufficient to port-forward 
ftp. So netgear routers almost certainly have logic to do the protocol 
monitoring and packet rewriting described.

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