Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
In article <UwkAe.135704$g5.53111@twister.nyroc.rr.com>, chandra
<chandra@rochester.rr.com> wrote:
> Hi
>
> i have below config
>
> Asus sli delux
>
> my monitor has built in speakers, i connected the monitor speakers in
> head phone jack behind the case.
> i also have two extra small speakers. i connected them into the jack of
> rear, side and woofer speakers, but there is not sound from them.
> am i doing the right thing, or is there any way that i need to connect.
>
> can some one shead light on the issue
>
>
> Regards
> chandra
You should be using amplified computer speakers. These boost
the weak signals from the computer sound output.
Typical AC'97 sound output on a computer is 32 ohms for front
speakers and 600 ohms for rear or center/sub outputs. The lower
the number, the stronger the output drive. The 32 ohm output
is suitable for driving headphones, and if you plugged in
unamplified speakers, you might get a tiny bit of sound from
them.
The 600 ohm outputs, on the other hand, if connected to
unamplified speakers, will give virtually no output (only a
few milliwatts maybe). So the weaker channels definitely need
amplification.
Some of the (clever) sound chips now, use jack sensing to
determine what has been plugged in. Sometimes, you may
need to select the speaker configuration from a control
panel, to get all the jacks to work. If the sound chip is
set to "stereo", there might not be any signal on the other
jacks. Select the number of channels that makes sense, whether
you want 4 channels or a stereo clone mode. Note that the
sound chip drivers may not support the mode you wish to use,
so it is a bit of a tossup as to whether what you are
attempting will be supported correctly from an acoustic
perspective (i.e. Selecting 4.1 mode, and using only
four speakers, might give weak bass output etc. Selecting
a 6 channel mode and plugging in only two speakers would
sound weird also. The audio signals are computed by the
sound chip and driver, to be acoustically correct when
the exact speaker configuration selected in the control
panel, has been plugged into the jacks.)
Product info can be found here for the ALC850 chip:
http://www.realtek.com.tw/products/products1-2.aspx?modelid=2003101
HTH,
Paul
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