Re: ALSA sound recording frustration

[Napoleon <rri0187@attglobal.net>]

Tzafrir Cohen wrote:
> On Thu, Nov 27, 2008 at 11:01:01AM -0600, lee wrote:
> > On Thu, Nov 27, 2008 at 09:38:40AM -0500, Mark Neidorff wrote:
> >
> > > also want to be able to record sound from the stereo headphones jack of my 
> > > radio and the stereo audio out from my XM radio.
> > The headphone connector is for headphones, it is not for connecting
> > recording devices: If the voltage and/or current are too high/much,
> > you can damage the soundcard.
>
> Last time I looked my headphones had no independent power source of 
> their own. The headphones output provides a certain current to the
> headphones. 
>
> Any other device connected there would also be feeding on that and would
> not provide power. 

Not necessarily true.  Some devices are meant to use powered mics, and
will therefore have power on the connector.

Hence the voltage of the power it does not provide
> cannot really damage your sound card that way.

Again, incorrect.

Additionally, to much of an impedance mismatch could in itself damage
the sound card.

> You had some interesting observation regarding the definition of Volt.
> If you have any comments on the definition in wikipedia, please note
> them on the comments page of the relevant value.
>
> This is an off-topic thread. Let's just drop it. On Debian the
> definition of "Volt" is "The result from lmsensors, multiplied by factor
> A plus factor B".

Which is why is is important to correct misinformation on the list.