🚀 go-pugleaf

On Sat, 20 Apr 2002 10:06:02 -0400, "David Evennou"
<dae@data-masters.com> wrote:

>I have a "Line Out" from a mixer that I want to record from. HP
>said to use the "Mic" input. I tried that, but the impedance mismatch is so
>great that it won't work. After all, a "Line Out" generates something like
>one volt output signal and a microphone does not generate a voltage.

It does, but a much smaller one, typically 10mV.

>I can't imagine a company like HP telling me to try the "mic" input for a "Line"
>signal.

It might work for a signal that can be turned down to a very low
level, though. BTW, mic inputs are usually mono, while line inputs are
stereo.

What you need to do is put a resistive divider between the line signal
and the mike to reduce the level. If you can't find someone able to do
it for you, let me know and I'll describe it in detail.

In another list, I've been taking part in a discussion which has
shown that some IBM laptops have a mono 'mic in' socket that
magically turns into a stereo line in socket when one enables the
Windows mixer's 'line in' channel on record. This doesn't apply on
the current X-range, which have a 'line in' jack hidden round the
back.

FWIW, I've tried this on my (dreadful) Sony laptop and it doesn't
work there. Since purchasing this Sony 'multimedia' machine, I've
bought 2 other machines - making sure that both (Acer and Asus)
had line in sockets and a knob for a volume control.

Another thing to watch out for is that laptop mic input sockets
are wired as mono jacks (tip and sleeve), whereas, for example,
minidisk microphone jacks are wired as stereo (tip and shorter
sleeve + ring and shorter sleeve). This makes the lead from, say,
a mono mic look the same, but be wired differently. What a mess it
all is!

Bill

Michael Warner <mvw@ozemail.com.au> wrote in message
news:5363cu0oo8bda21svg9l4gn2np05bc2l4d@4ax.com...
> On Sat, 20 Apr 2002 10:06:02 -0400, "David Evennou"
> <dae@data-masters.com> wrote:
>
> >I have a "Line Out" from a mixer that I want to record from. HP
> >said to use the "Mic" input. I tried that, but the impedance
mismatch is so
> >great that it won't work. After all, a "Line Out" generates
something like
> >one volt output signal and a microphone does not generate a
voltage.
>
> It does, but a much smaller one, typically 10mV.
>
> >I can't imagine a company like HP telling me to try the "mic"
input for a "Line"
> >signal.
>
> It might work for a signal that can be turned down to a very low
> level, though. BTW, mic inputs are usually mono, while line
inputs are
> stereo.
>
> What you need to do is put a resistive divider between the line
signal
> and the mike to reduce the level. If you can't find someone able
to do
> it for you, let me know and I'll describe it in detail.

You probably want to get a USB audio device so that you can do this. There
are several and they don't cost too much.
That way you'll get better (stereo) audio input/output.

Rgds Pete
"Michael Warner" <mvw@ozemail.com.au> wrote in message
news:5363cu0oo8bda21svg9l4gn2np05bc2l4d@4ax.com...
> On Sat, 20 Apr 2002 10:06:02 -0400, "David Evennou"
> <dae@data-masters.com> wrote:
>
> >I have a "Line Out" from a mixer that I want to record from. HP
> >said to use the "Mic" input. I tried that, but the impedance mismatch is
so
> >great that it won't work. After all, a "Line Out" generates something
like
> >one volt output signal and a microphone does not generate a voltage.
>
> It does, but a much smaller one, typically 10mV.
>
> >I can't imagine a company like HP telling me to try the "mic" input for a
"Line"
> >signal.
>
> It might work for a signal that can be turned down to a very low
> level, though. BTW, mic inputs are usually mono, while line inputs are
> stereo.
>
> What you need to do is put a resistive divider between the line signal
> and the mike to reduce the level. If you can't find someone able to do
> it for you, let me know and I'll describe it in detail.

Thanks Michael,

I tried adjusting the volume of the Line-In on the Windows Mixer, but the
audio was still distorted. Also, I noticed the the VU meters were pegged on
my tape deck during the test. When I unplugged the audio cable from the
laptop mic input, the VU meters went back to normal. This is a puzzle.

I only need mono to record the Church Sermon. I discussed the resistor
devider idea with a friend. Do you think I may be introducing some problems
with frequency response? Do you think a 1000 to 1 divider will do the trick?


Thanks,
David

"Michael Warner" <mvw@ozemail.com.au> wrote in message
news:5363cu0oo8bda21svg9l4gn2np05bc2l4d@4ax.com...
> On Sat, 20 Apr 2002 10:06:02 -0400, "David Evennou"
> <dae@data-masters.com> wrote:
>
> >I have a "Line Out" from a mixer that I want to record from. HP
> >said to use the "Mic" input. I tried that, but the impedance mismatch is
so
> >great that it won't work. After all, a "Line Out" generates something
like
> >one volt output signal and a microphone does not generate a voltage.
>
> It does, but a much smaller one, typically 10mV.
>
> >I can't imagine a company like HP telling me to try the "mic" input for a
"Line"
> >signal.
>
> It might work for a signal that can be turned down to a very low
> level, though. BTW, mic inputs are usually mono, while line inputs are
> stereo.
>
> What you need to do is put a resistive divider between the line signal
> and the mike to reduce the level. If you can't find someone able to do
> it for you, let me know and I'll describe it in detail.

Thanks, Pete. I am looking into the new external SoundBlaster named
"Extigy".

David

"Pete Fraser" <pete.fraser@at.frasersoft.dot.net> wrote in message
news:3cc3dfb9_1@dnews...
> You probably want to get a USB audio device so that you can do this. There
> are several and they don't cost too much.
> That way you'll get better (stereo) audio input/output.
>
> Rgds Pete
> "Michael Warner" <mvw@ozemail.com.au> wrote in message

On Mon, 22 Apr 2002 09:29:10 -0400, "David Evennou"
<dae@data-masters.com> wrote:

>Thanks Michael,
>
>I tried adjusting the volume of the Line-In on the Windows Mixer, but the
>audio was still distorted.

But you don't have a line-in jack - did you mean mic in? Even so, a
line-level signal would distort the mic input's preamp, hence the
distortion even at low output volume.

>Also, I noticed the the VU meters were pegged on
>my tape deck during the test. When I unplugged the audio cable from the
>laptop mic input, the VU meters went back to normal. This is a puzzle.

Hard to say why without seeing the circuitry of your tape deck and mic
input.

>I only need mono to record the Church Sermon. I discussed the resistor
>devider idea with a friend. Do you think I may be introducing some problems
>with frequency response? 

Probably not.

> Do you think a 1000 to 1 divider will do the trick?

I would try 100 to 1 first, but be aware that the impedance of the mic
input may upset this by being low. I would establish that first, but
it requires test gear.

"Michael Warner" <mvw@ozemail.com.au> wrote in message
news:1te8cu0598adcffu3dj2dqcu9bvi299ifg@4ax.com...
> On Mon, 22 Apr 2002 09:29:10 -0400, "David Evennou"
> <dae@data-masters.com> wrote:
<snip>
>
> > Do you think a 1000 to 1 divider will do the trick?
>
> I would try 100 to 1 first, but be aware that the impedance of the mic
> input may upset this by being low. I would establish that first, but
> it requires test gear.

From what little I remember of the electronics I did years ago (gawd, has it
been a decade already?  How time flies...) the matter of impedence in audio
systems is generally solved with an impedence matching transformer.  They're
smaller than the end digit of my little finger and sell for about $0.20.

Of course I could just be thinking about output difference between line-out
and speaker-out.  It's been a while.

--
Corey Murtagh
The Electric Monk
"Quidquid latine dictum sit, altum viditur."

Normally a Mic input has  a an impedance of about 1k. It also probably has a
sensitivity of about 2-5mV. The output from a mixer is normally either 1V
(0dBv) or 330mV (-10dBv). If the bottom resistor of the potential divider is
1k, then the top leg of 100k will probably give you a reasonable signal.
Note however that Mic inputs on soundcards normally pick up more noise from
the PSU, though if its from a portable running off a battery it shouldn't be
a problem. Also note that as you're reducing the signal from your source and
then amplifying it again, the noise level (hiss) will be increased, relative
to using a line level input signal. Of course for a church sermon this will
probably not be a problem.
Rgds Pete (Part time sound engineer/ex. audio design engineer)

"> > Do you think a 1000 to 1 divider will do the trick?
>
> I would try 100 to 1 first, but be aware that the impedance of the mic
> input may upset this by being low. I would establish that first, but
> it requires test gear.