[LAU] question related output level and sound card

[Clemens Ladisch]

Djého Youn wrote:
> Last time I had a gig in a club where the sound system was really huge, and I noticed that my signal wasn't loud enough.
>
> I was using just headphone jack out from my laptop

I guess such a sound system does not behave like a pair of headphones.

Apparently, your laptop does not have a line output jack?

> I've been told that if I use a dedicated sound card, my output signal can boost significantly.

You need _some_ device with a line-level output, either a line out
jack on your laptop, or an external device.

> although it sounds like it makes sense, I doubt it a little bit because I don't see any output pre-amps...etc. on the sound cards spec.

Amplifiers are needed if the output is supposed to _drive_ the actual
speakers, i.e., if the signal is supposed to have enough energy to move
the speaker membrane.  (This is quite easy with the tiny speakers used
in headphones.)

A line output does not have much power; its only purpose is to provide
a voltage level that is then measured and applied to the speaker outputs
of a 'real' amplifier.  (Neither your laptop nor a USB device would be
capable of providing thousands of watts for that really huge sound
system.)

The problem with the headphone jack is that it does not provide the
correct voltage level when it is connected to a line input.

> what card you recommend to me?

Any simple USB stereo playback device with line outputs.

> http://www.thomann.de/pl/akai_eie_pro.htm

That is overkill.  In theory, something cheap like this is adequate:
http://www.thomann.de/pl/behringer_ucontrol_uca_222.htm


Regards,
Clemens