Foo (mic in)

The Mic In on my Inspiron 1200 goes dead at random. I feed it with
a mixer line-out and 3.5mm stereo connector. (Real Encoder encodes
24/7 from it, dumping a 10MB file every 3 hours into a nice calendar
file arrangement, in case I want to go back to something.)

Recently it's been smoothly going dead (not scratchy, just an audio
dropoff to zero except for some very very weak crosstalk-type leakage).

Cleaning the plug with brush DeOxit (great stuff) seemed to help - it managed
to go about four days without doing it again. Cleaning the plug cleans
both plug and jack, as you plug it in and out several times.

Maybe there's a NC or NO connection inside that needs the cleaning. I
spritzed a little spritz Deoxit in there, but so far no fix, unless
it manages to work eternally from now on. (It failed a couple times
after the spritz.) On the other hand, it's hard to clean any such
contact by plugging in and out repeatedly, so maybe it just needs more
working around.

Unless there's some software that's crapping out that's awakened anew
by fussing with the jack, another possibility.

Another possibility is that it really wants a 3.5mm mono plug, and something
in the stereo plug is very near to shorting to ground, and sometimes does.
The manual doesn't say.
--


On the internet, nobody knows you're a jerk.

The mic. lead could esily be broken where it goes inside the molded
plug... try by using it and wobbling the wire at the same time.

If this is the case then simply chop the plug of and have a new plug
fitted, you could do this yourself with a little dab at at soldering, of
course you'll need a small iron.

Sometimes the mic. socket can become loose or the connections
tarnished, simply squirt some switch cleaner...use nothing else and
certainly NOT Carbon Tetrachloride as this WILL melt the plastic, use
only the proper stuff.

I would squirt some on the plug... not in the hole and then simply
insert the plug and twist it round a couple of times.

Note that am assuming the plugs are those 3.5mm miniature headphone
type jacks.

Also check the wires by giving the 'wobble test' at the mic. end as
well. It's all the twisting, curling and pulling what causes the wire
to break. The best way really is to try the mic elsewhere or try another
mic.. as it could easily be the mobo socket.. or even a fault on the
sound card or whatever.

davy

davy wrote:

The mic. lead could esily be broken where it goes inside the molded
plug... try by using it and wobbling the wire at the same time.

If this is the case then simply chop the plug of and have a new plug
fitted, you could do this yourself with a little dab at at soldering, of
course you'll need a small iron.

Sometimes the mic. socket can become loose or the connections
tarnished, simply squirt some switch cleaner...use nothing else and
certainly NOT Carbon Tetrachloride as this WILL melt the plastic, use
only the proper stuff.

I would squirt some on the plug... not in the hole and then simply
insert the plug and twist it round a couple of times.

Note that am assuming the plugs are those 3.5mm miniature headphone
type jacks.

Also check the wires by giving the 'wobble test' at the mic. end as
well. It's all the twisting, curling and pulling what causes the wire
to break. The best way really is to try the mic elsewhere or try another
mic.. as it could easily be the mobo socket.. or even a fault on the
sound card or whatever.

davy

Definitely not the plug or the wire. In fact the thing has to be
physically unplugged (not wobbled or twisted) to get good contact again.

I suspect some interior switching in the jack, that's got a dirty
contact; it closes or opens when you insert a plug.

It _may_ be it expects a mono plug and is getting a stereo one, but
that doesn't really explain how it works for (sometimes) days and then
quits.

It's not plugged or unplugged except to fix it. It's a permanent
arrangement.

This quitting business makes it most unacceptable, though.

DeOxit is the best contact cleaner around. I get mine here
http://www.partsexpress.com/pe/showd...number=341-215

(brush for general jack cleaning ; rechargeable battery contacts ;
high power mains plugs that get hot [brush a little on the jack, and work in
and out of the wall plug until it comes out clean] ; audio cables that
don't work solidly. But it's not fixing this.

It appears to melt carbon potentiometers or something, but fixes them
nevertheless. The knob just goes very sluggish after a few hours
and clears up after a few days. The offending scratchiness is gone
though.)

There's also spray versions.

--


On the internet, nobody knows you're a jerk.

There is some reason to suspect tha the loss of audio line-in signal is
due to a software timeout in the encoding; killing the driver.

In particular, under load, if it doesn't get samples for a while, or
doesn't manage to get rid of them before its buffer overflows, it quits.

I managed to provoke the dropout with heavy google earth processor use.

Unplugging and plugging the audio line-in jack reinitializes it.
--


On the internet, nobody knows you're a jerk.

Ron Hardin wrote:

There is some reason to suspect tha the loss of audio line-in signal is
due to a software timeout in the encoding; killing the driver.

In particular, under load, if it doesn't get samples for a while, or
doesn't manage to get rid of them before its buffer overflows, it quits.

I managed to provoke the dropout with heavy google earth processor use.

Unplugging and plugging the audio line-in jack reinitializes it.

That also explains why DeOxit didn't fix it. I've never found a dirty connection
it didn't remedy before.
--


On the internet, nobody knows you're a jerk.

Ron Hardin;316723 Wrote:


It _may_ be it expects a mono plug and is getting a stereo one, but
that doesn't really explain how it works for (sometimes) days and then
quits.


You have a good point here. Come to think I have had issues with these
mini 2.5mm and 3.5 mm jack plugs, even mono ones in home entertainment
systems and portable equipment, never the standard 6mm headphone jacks
though....

.... funny how I always refer to these as headphone jacks and the
smaller ones as mic plugs, even in the trade , stems from the days
of repairing radios and TVs... and being a radio ham.

Don't know if you noted with 'some' of these mini jacks there seems to
be a little step or wedge between the top plastic section where the
actual pins come out.

As suspected no doubt the contacts can also get worn, these are only
flimsy metal contacts.

davy

On Fri, 28 Sep 2007 16:05:24 -0400, Ron Hardin
wrote:

The Mic In on my Inspiron 1200 goes dead at random. I feed it with
a mixer line-out and 3.5mm stereo connector. (Real Encoder encodes
24/7 from it, dumping a 10MB file every 3 hours into a nice calendar
file arrangement, in case I want to go back to something.)

Ron,

I see that you are into recording, and I am seeking a good program to
use a PC's internal mic to be able to record meetings.

I have two laptops with built-in microphones.

I also have a USB microphone that is mind-boggling in how well it
picks things up. I can walk around my apartment and talk in a normal
voice and use it for voice over IP.

http://tinyurl.com/348dne

I only have the green part itself. It's amazing.

However, I want to be able to record unobtrusively, in other words,
record a meeting but for it not to be apparent that I am recording it.

I need to check the law in WI regarding stealth recording.

What I need is software that enables the built-in mics to pick up well
enough to hear all parties in a meeting.

I use freeware software Audacity, which is great for talking into my
computer, but it doesn't pick up well enough for meetings.

If you know of any software for this please let me know.

I do understand that your uses of line in may be totally unrelated to
this.

Journey wrote:

On Fri, 28 Sep 2007 16:05:24 -0400, Ron Hardin
wrote:

The Mic In on my Inspiron 1200 goes dead at random. I feed it with
a mixer line-out and 3.5mm stereo connector. (Real Encoder encodes
24/7 from it, dumping a 10MB file every 3 hours into a nice calendar
file arrangement, in case I want to go back to something.)

Ron,

I see that you are into recording, and I am seeking a good program to
use a PC's internal mic to be able to record meetings.

I have two laptops with built-in microphones.

I also have a USB microphone that is mind-boggling in how well it
picks things up. I can walk around my apartment and talk in a normal
voice and use it for voice over IP.

http://tinyurl.com/348dne

I only have the green part itself. It's amazing.

However, I want to be able to record unobtrusively, in other words,
record a meeting but for it not to be apparent that I am recording it.

I need to check the law in WI regarding stealth recording.

What I need is software that enables the built-in mics to pick up well
enough to hear all parties in a meeting.

I use freeware software Audacity, which is great for talking into my
computer, but it doesn't pick up well enough for meetings.

If you know of any software for this please let me know.

I do understand that your uses of line in may be totally unrelated to
this.

I don't know about meetings ; I use traditional mics for outdoor bird song
recording, fed into a Behringer mixer that routes all the audio around
between radios and a small FM transmitter and the computer at once ; it's
hardly unobtrusive.

The usual problem with indoor recording is echos that you don't notice
in stereo but are intelligibility-killing in monaural. Usually indoors
everybody is loud enough, just not clear enough, for this reason; unless
you're close enough so that the unechoed sound is much louder than the
echoed sound. Which is how distance kills it.

Voice-recording MP3 players are certainly unobtrusive, if you use that instead.
But they'll always have the same non-stereo problem indoors.
--


On the internet, nobody knows you're a jerk.

Hmm.

I went to a Behringer UCA202 UCB audio device,
which encodes and decodes audio and is plug
and play.

It instead of dropping to zero audio at random,
goes to high gain audio suddenly, at about the
same odd rare times.

So still 100% reliability is elusive.

(You get the UCB as the default input and output
device, see Start/Control Panel/Sounds and Audio
Devices/Audio. You want to change the default
play device back to the Sigma Tel, probably.)

It turns out that you can record from both
devices at once, just using -ac 0 for one
Real Producer (default device) and -ac 1
for a second one (the other device). Maybe
that's how I'll have to get reliability,
assuming they don't both crap out for the same
reason : dual recording redundancy.

(``-ac'' = audio capture device)

Slight disadvantage of the UCB : it takes about
15% of the CPU time, instead of some unnoticeable
amount. The extra time is in the total but not
associated with any process. In fact it seems
to be in the System idle time category. But
the CPU usage total shows it, and things like
virus scans run much longer, so it's real.
--


On the internet, nobody knows you're a jerk.

Hmm...

A real encoding where the Behringer UCB device failed is
http://home.att.net/~rhhardina/UCA202.ra (30 sec)

Meantime I was monitoring the input via the headphone monitor
on the UCB, and it was unchanged.

Furthermore, if I run the actual volume way way down, the audio
recovers to its normal volume. But it's actually a very tiny
signal in at that point, and raising the volume even a tiny
bit causes it to go back into overload.

What does this mean? Probably, in fact almost undoubtedly,
that the encoder values come back as serial form, and something
has gotten out of sync, so that the very low bits are being
interpreted as the very highest bits. (Hence normal encoded
volume on what is actually the least significant bits; and quick
overflow if the lsb's are exceeded.)

THAT ALSO accounts for the onboard Sigmatel failure, except sort
of in the opposite direction, with the most significant bits shifting
themselves off into the low bit territory.

SO : who is responsible for not losing sync on what bit is what, in the
audio device world? XP? Some Dell driver? Real Producer itself?

--


On the internet, nobody knows you're a jerk.