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From: M.I.5� on 8 Apr 2008 02:47

"BillW50" <BillW50(a)aol.kom> wrote in message
news:47fa326c$0$6433$834e42db(a)reader.greatnowhere.com...
> In news:47f9cf72$1_1(a)glkas0286.greenlnk.net,
> M.I.5� typed on Mon, 7 Apr 2008 08:55:30 +0100:
>> "Paul" <nospam(a)needed.com> wrote in message
>> news:ft6kp3$esl$1(a)aioe.org...
>>> MikeCC4(a)yahoo.com wrote:
>>>> I have a gateway MX3563 laptop with windows XP home. I tried to use
>>>> a mcirophone for Yahoo messenger kind software. The microphone works
>>>> perfectly on my other laptops. However, it does not work on this
>>>> one; i.e. no sound or no voice can be heard by the person on the
>>>> other side. The microphone must not be broken because it works with
>>>> other laptops.
>>>>
>>>> I checked the device manager and did not find any problem. In fact,
>>>> I just used system restore CDs to completely reinstalled the laptop
>>>> to original manufacturer's condition. But I still cannot use any
>>>> microphones (I have two microphones both work on all other desktops
>>>> and laptops with Windows XP Home or Vista) with this Gateway laptop.
>>>> For the same reason, I cannot use any microphone to record anything
>>>> on this laptop. It is already out of warranty.
>>>>
>>>> Can anyone help? thanks!
>>>>
>>>> P.S. This problem happened quite long time ago. (it happened way
>>>> before I damaged my keyboard (as in my other post.))
>>>
>>> Plug a Walkman or a tape recorder into the microphone
>>> jack. Does the microphone jack produce a signal when that
>>> is present ? Anything with a line level output could be
>>> used to test the jack.
>>
>> A line level signal will vastly overdrive a microphone input.
>
> Hi M.I.5�! This is usually true of most, but not for some Gateway laptops
> at least (like the two MX6124 I have). They use the same jack for both the
> mic and the Line In. It even has separate levels for both as well. There
> is nothing to switch, it just autodetects and switches all by itself. I
> just checked the manual and it says nothing about the Line In feature. But
> I use it for both all of the time.
>

How on earth can it detect the difference between a line level jack and an
identical microphone jack?

Line in jacks are very uncommon on laptops and I would suggest that the
reason the manual doesn't mention it is because it isn't, in fact there.

Some Cardbus and Express Card plug in soundcards feature Mic in and Line in
on the same input jack, but the actual input has to be selected in the mixer
utility because there is no way for the card to tell the difference (as I
said the plugs are identical).


From: BillW50 on 8 Apr 2008 12:39
In news:47fb110a$1_1(a)glkas0286.greenlnk.net,
M.I.5� typed on Tue, 8 Apr 2008 07:47:38 +0100:
> "BillW50" <BillW50(a)aol.kom> wrote in message
> news:47fa326c$0$6433$834e42db(a)reader.greatnowhere.com...
>> In news:47f9cf72$1_1(a)glkas0286.greenlnk.net,
>> M.I.5� typed on Mon, 7 Apr 2008 08:55:30 +0100:
>>> "Paul" <nospam(a)needed.com> wrote in message
>>> news:ft6kp3$esl$1(a)aioe.org...
>>>> MikeCC4(a)yahoo.com wrote:
>>>>> I have a gateway MX3563 laptop with windows XP home. I tried to
>>>>> use a mcirophone for Yahoo messenger kind software. The
>>>>> microphone works perfectly on my other laptops. However, it does
>>>>> not work on this one; i.e. no sound or no voice can be heard by
>>>>> the person on the other side. The microphone must not be broken
>>>>> because it works with other laptops.
>>>>>
>>>>> I checked the device manager and did not find any problem. In
>>>>> fact, I just used system restore CDs to completely reinstalled
>>>>> the laptop to original manufacturer's condition. But I still
>>>>> cannot use any microphones (I have two microphones both work on
>>>>> all other desktops and laptops with Windows XP Home or Vista)
>>>>> with this Gateway laptop. For the same reason, I cannot use any
>>>>> microphone to record anything on this laptop. It is already out
>>>>> of warranty. Can anyone help? thanks!
>>>>>
>>>>> P.S. This problem happened quite long time ago. (it happened way
>>>>> before I damaged my keyboard (as in my other post.))
>>>>
>>>> Plug a Walkman or a tape recorder into the microphone
>>>> jack. Does the microphone jack produce a signal when that
>>>> is present ? Anything with a line level output could be
>>>> used to test the jack.
>>>
>>> A line level signal will vastly overdrive a microphone input.
>>
>> Hi M.I.5�! This is usually true of most, but not for some Gateway
>> laptops at least (like the two MX6124 I have). They use the same
>> jack for both the mic and the Line In. It even has separate levels
>> for both as well. There is nothing to switch, it just autodetects
>> and switches all by itself. I just checked the manual and it says
>> nothing about the Line In feature. But I use it for both all of the
>> time.
>
> How on earth can it detect the difference between a line level jack
> and an identical microphone jack?

The signal level of a microphone is typically 40 to 60 dB lower (a
factor of 100 to 1000) than a line input. The gain of a single OP amp
back in the 80's if I remember correctly had a max gain of 50,000 times.
So an AGC (automatic gain control) circuit using one OP amp is well
within this range.

Although I suspect it is more designed like my tiny FM transmitter
works. As if it detects voltage less than say 100mv for a minute, it
shuts off. Although in this case on my laptop, throws it in mic mode. If
it detects 100mv or higher, throws it into Input mode.

> Line in jacks are very uncommon on laptops and I would suggest that
> the reason the manual doesn't mention it is because it isn't, in fact
> there.

Hmm... until my purchase of these Gateway MX6124 laptops back in 2006, I
always had aux in jacks on my laptops. So I thought they were very
common.

> Some Cardbus and Express Card plug in soundcards feature Mic in and
> Line in on the same input jack, but the actual input has to be
> selected in the mixer utility because there is no way for the card to
> tell the difference (as I said the plugs are identical).

Hmm... you have me curious. Well it doesn't take long to hookup my MP3
player to my mic jack on this laptop so here goes. Well I remembered
somewhat incorrectly. While there is a line level control in the mixer,
it has no effect. But the mic level does. And the iRiver T10 FM/MP3
player has a very high output level when compared to most other MP3/CD
players. But I have noticed that 50% volume is about as high as you can
go with most input jacks on most equipment without distortion from a
T10.

This laptop, like most laptops and desktop sound card mixers I've seen
in the last 10 years also has a mic boost toggle in the mixer. And
generally a dynamic mic just barely has enough power for acceptable
levels when the boost is toggled on and the gain set as high as it can
go.

Although when the mic boost is toggled off, the dynamic mic level can
barely be heard. Although feed a line in level into the mic jack with
the boost toggled off, it is just perfect. And with the T10 connected to
the mic jack at 50% volume, it is again just perfect.

So I remembered wrong and the mixer mic boost toggle switches between
input or mic levels. Although as an engineer, it isn't a big deal to
design a circuit to automatically switch between the two modes
automatically. But I guess nobody has bothered yet in the laptop market.

--
Bill

From: Barry Watzman on 8 Apr 2008 22:16
A Line-IN level is about 1 volt (and sometimes double or triple that),
and a mic in level is 1 to 5 millivolts (millivolt = .001 volt). It
would be fairly easy to make a circuit that would work for both, the key
would be to keep from damaging the mic circuit when a line-level signal
was applied.

Different computer sound cards use two different types of microphones.
Some use dynamic microphones, some use capacitance microphones. If the
mic circuit doesn't seem to work, the first thought I would have is "am
I using the right type of microphone?". Capacitance and dynamic
microphones are as different as night and day.


M.I.5� wrote:
> "BillW50" <BillW50(a)aol.kom> wrote in message
> news:47fa326c$0$6433$834e42db(a)reader.greatnowhere.com...
>> In news:47f9cf72$1_1(a)glkas0286.greenlnk.net,
>> M.I.5� typed on Mon, 7 Apr 2008 08:55:30 +0100:
>>> "Paul" <nospam(a)needed.com> wrote in message
>>> news:ft6kp3$esl$1(a)aioe.org...
>>>> MikeCC4(a)yahoo.com wrote:
>>>>> I have a gateway MX3563 laptop with windows XP home. I tried to use
>>>>> a mcirophone for Yahoo messenger kind software. The microphone works
>>>>> perfectly on my other laptops. However, it does not work on this
>>>>> one; i.e. no sound or no voice can be heard by the person on the
>>>>> other side. The microphone must not be broken because it works with
>>>>> other laptops.
>>>>>
>>>>> I checked the device manager and did not find any problem. In fact,
>>>>> I just used system restore CDs to completely reinstalled the laptop
>>>>> to original manufacturer's condition. But I still cannot use any
>>>>> microphones (I have two microphones both work on all other desktops
>>>>> and laptops with Windows XP Home or Vista) with this Gateway laptop.
>>>>> For the same reason, I cannot use any microphone to record anything
>>>>> on this laptop. It is already out of warranty.
>>>>>
>>>>> Can anyone help? thanks!
>>>>>
>>>>> P.S. This problem happened quite long time ago. (it happened way
>>>>> before I damaged my keyboard (as in my other post.))
>>>> Plug a Walkman or a tape recorder into the microphone
>>>> jack. Does the microphone jack produce a signal when that
>>>> is present ? Anything with a line level output could be
>>>> used to test the jack.
>>> A line level signal will vastly overdrive a microphone input.
>> Hi M.I.5�! This is usually true of most, but not for some Gateway laptops
>> at least (like the two MX6124 I have). They use the same jack for both the
>> mic and the Line In. It even has separate levels for both as well. There
>> is nothing to switch, it just autodetects and switches all by itself. I
>> just checked the manual and it says nothing about the Line In feature. But
>> I use it for both all of the time.
>>
>
> How on earth can it detect the difference between a line level jack and an
> identical microphone jack?
>
> Line in jacks are very uncommon on laptops and I would suggest that the
> reason the manual doesn't mention it is because it isn't, in fact there.
>
> Some Cardbus and Express Card plug in soundcards feature Mic in and Line in
> on the same input jack, but the actual input has to be selected in the mixer
> utility because there is no way for the card to tell the difference (as I
> said the plugs are identical).
>
>
From: M.I.5� on 10 Apr 2008 03:28

"BillW50" <BillW50(a)aol.kom> wrote in message
news:47fba1e0$0$6436$834e42db(a)reader.greatnowhere.com...
> In news:47fb110a$1_1(a)glkas0286.greenlnk.net,
> M.I.5� typed on Tue, 8 Apr 2008 07:47:38 +0100:
>> "BillW50" <BillW50(a)aol.kom> wrote in message
>> news:47fa326c$0$6433$834e42db(a)reader.greatnowhere.com...
>>> In news:47f9cf72$1_1(a)glkas0286.greenlnk.net,
>>> M.I.5� typed on Mon, 7 Apr 2008 08:55:30 +0100:
>>>> "Paul" <nospam(a)needed.com> wrote in message
>>>> news:ft6kp3$esl$1(a)aioe.org...
>>>>> MikeCC4(a)yahoo.com wrote:
>>>>>> I have a gateway MX3563 laptop with windows XP home. I tried to
>>>>>> use a mcirophone for Yahoo messenger kind software. The
>>>>>> microphone works perfectly on my other laptops. However, it does
>>>>>> not work on this one; i.e. no sound or no voice can be heard by
>>>>>> the person on the other side. The microphone must not be broken
>>>>>> because it works with other laptops.
>>>>>>
>>>>>> I checked the device manager and did not find any problem. In
>>>>>> fact, I just used system restore CDs to completely reinstalled
>>>>>> the laptop to original manufacturer's condition. But I still
>>>>>> cannot use any microphones (I have two microphones both work on
>>>>>> all other desktops and laptops with Windows XP Home or Vista)
>>>>>> with this Gateway laptop. For the same reason, I cannot use any
>>>>>> microphone to record anything on this laptop. It is already out
>>>>>> of warranty. Can anyone help? thanks!
>>>>>>
>>>>>> P.S. This problem happened quite long time ago. (it happened way
>>>>>> before I damaged my keyboard (as in my other post.))
>>>>>
>>>>> Plug a Walkman or a tape recorder into the microphone
>>>>> jack. Does the microphone jack produce a signal when that
>>>>> is present ? Anything with a line level output could be
>>>>> used to test the jack.
>>>>
>>>> A line level signal will vastly overdrive a microphone input.
>>>
>>> Hi M.I.5�! This is usually true of most, but not for some Gateway
>>> laptops at least (like the two MX6124 I have). They use the same
>>> jack for both the mic and the Line In. It even has separate levels
>>> for both as well. There is nothing to switch, it just autodetects
>>> and switches all by itself. I just checked the manual and it says
>>> nothing about the Line In feature. But I use it for both all of the
>>> time.
>>
>> How on earth can it detect the difference between a line level jack
>> and an identical microphone jack?
>
> The signal level of a microphone is typically 40 to 60 dB lower (a factor
> of 100 to 1000) than a line input. The gain of a single OP amp back in the
> 80's if I remember correctly had a max gain of 50,000 times. So an AGC
> (automatic gain control) circuit using one OP amp is well within this
> range.
>
> Although I suspect it is more designed like my tiny FM transmitter works.
> As if it detects voltage less than say 100mv for a minute, it shuts off.
> Although in this case on my laptop, throws it in mic mode. If it detects
> 100mv or higher, throws it into Input mode.
>
>> Line in jacks are very uncommon on laptops and I would suggest that
>> the reason the manual doesn't mention it is because it isn't, in fact
>> there.
>
> Hmm... until my purchase of these Gateway MX6124 laptops back in 2006, I
> always had aux in jacks on my laptops. So I thought they were very common.
>
>> Some Cardbus and Express Card plug in soundcards feature Mic in and
>> Line in on the same input jack, but the actual input has to be
>> selected in the mixer utility because there is no way for the card to
>> tell the difference (as I said the plugs are identical).
>
> Hmm... you have me curious. Well it doesn't take long to hookup my MP3
> player to my mic jack on this laptop so here goes. Well I remembered
> somewhat incorrectly. While there is a line level control in the mixer, it
> has no effect. But the mic level does. And the iRiver T10 FM/MP3 player
> has a very high output level when compared to most other MP3/CD players.
> But I have noticed that 50% volume is about as high as you can go with
> most input jacks on most equipment without distortion from a T10.
>

The usual way of controling the input, is that either the MIC in or LINE in
has to be muted. The mixer then switches the sound card input to the other
mode.

> This laptop, like most laptops and desktop sound card mixers I've seen in
> the last 10 years also has a mic boost toggle in the mixer. And generally
> a dynamic mic just barely has enough power for acceptable levels when the
> boost is toggled on and the gain set as high as it can go.
>
> Although when the mic boost is toggled off, the dynamic mic level can
> barely be heard. Although feed a line in level into the mic jack with the
> boost toggled off, it is just perfect. And with the T10 connected to the
> mic jack at 50% volume, it is again just perfect.
>
> So I remembered wrong and the mixer mic boost toggle switches between
> input or mic levels. Although as an engineer, it isn't a big deal to
> design a circuit to automatically switch between the two modes
> automatically. But I guess nobody has bothered yet in the laptop market.
>

The MIC input on most sound cards these days is set for condenser
microphones. And even with these you usually have to set the 20dB boost on
for most purposes. Some, but not all, even provide the power for the
impedance converter, but the voltage is not standardised.

Although it would be fairly easy to build such an AGC circuit, it wouldn't
be a practical proposition. If the line input had no signal for any
appreciable time, it would ramp the gain up to MIC levels. As soon as a
full amplitude signal appeared, the input would be well overdriven for the
brief period that it takes the circuit to adjust its gain. If that
overdriven signal was fed to a class D amplifier (not uncommon these days in
PC sound systems) driving speakers, the speakers and possibly the amplifier
output could easily sustain damage (and even class A, AB, and B systems
might have a thing or two to say on the matter)



From: BillW50 on 11 Apr 2008 18:43
In news:47fdbdad$1_1(a)glkas0286.greenlnk.net,
M.I.5� typed on Thu, 10 Apr 2008 08:28:46 +0100:
> The usual way of controling the input, is that either the MIC in or
> LINE in has to be muted. The mixer then switches the sound card
> input to the other mode.

Hi M.I.5�! Oh I know, but that isn't what I meant. I mean my mixer has a
Line In setting, but there isn't any hardware there. All I have for
input is just the Mic input and that is all.

> The MIC input on most sound cards these days is set for condenser
> microphones. And even with these you usually have to set the 20dB
> boost on for most purposes. Some, but not all, even provide the
> power for the impedance converter, but the voltage is not
> standardised.

That is very odd. Everything it seems to me is set for dynamic mics.
Maybe UK stuff is different than American stuff. I love condenser mics
over dynamic btw. I just don't see them very often here except on higher
priced electronics. And then sometimes they still use dynamic mics.

> Although it would be fairly easy to build such an AGC circuit, it
> wouldn't be a practical proposition. If the line input had no signal
> for any appreciable time, it would ramp the gain up to MIC levels. As
> soon as a full amplitude signal appeared, the input would be well
> overdriven for the brief period that it takes the circuit to adjust
> its gain. If that overdriven signal was fed to a class D amplifier
> (not uncommon these days in PC sound systems) driving speakers, the
> speakers and possibly the amplifier output could easily sustain
> damage (and even class A, AB, and B systems might have a thing or two
> to say on the matter)

Well you can only push the final amps so far and you won't get anymore
out of them. I bought a Marantz 4400 quad back in '76 with Sansui
SP-X9000 speakers. The receiver in quad mode only put out 50 watts times
four channels. It would put out 125 watts in 2 channels. Nonetheless,
each speaker can handle 220 watts each. So you can do anything with the
input and never blow out the speakers. You could even plug the speakers
directly into a 110VAC outlet, and you still couldn't blow out the
speakers. At that time, Bose 901 was also popular speakers. I would have
purchased them, but too many had blown out when someone dropped a
stylists on a vinyl record. And that can't happen with the Sansui
speakers.

--
Bill

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