On Tue, Jun 10, 2008 at 7:27 PM, James G. Sack (jim) <[EMAIL PROTECTED]> wrote:
> Karl Cunningham wrote:
>> On 6/10/2008 4:22 PM, Carl Lowenstein wrote:
>>> I have a relatively cheap SoundBlaster card, lspci sees it as
>>> "Creative Labs SB Audigy LS". It has 4 jacks on the back panel,
>>> colored blue, green, black, and orange. There are mysterious icons
>>> next to the jacks. In simple words, what is the function of each one?
>>>
>>> By fumbling around, I have found that the green one plays the system
>>> test sound into a set of unpowered speakers.
>>
>> This is specified in the PC99 System Design Guide, promulgated by Intel
>> and Microsoft years ago. It's now being sold in hard copy, but is still
>> available as a PDF here:
>> http://www-pc.uni-regensburg.de/hardware/TECHDOK/PC_99_1.pdf
>>
>> This used to be widely available on the Internet and apparently has been
>> taken down from most websites, probably to support book sales.
>>
>> The color coding is described in section 3.18.3, and some of the icons
>> appear in Appendix A.
>
> Another useful reference. Thanks for the post.
>
Well, useful as a starting point. It stimulated me to take out the
magnifier and flashlight and look at the back panel of the sound card
and also at the document that I found at the Creative Labs web site.
The icons in Appendix A must have been designed by an engineer (in the
worst connotation of the word). Audio in and audio out are both sets
of concentric circular wavefronts, with a radial line. The line has a
spot at the inner end for the input, a spot at the outer end for the
output. Takes a lot of careful looking.
The color coding described in section 3.18.3 helps me for sure to tell
that the keyboard is purple and the mouse is green.
With some imagination, I can also see the following:
The blue jack with the Audio In icon is "Audio line in Light blue"
Or maybe it is also Microphone input since it has a microphone icon too.
But microphone jacks are supposed to be pink.
The green jack with the Audio Out icon is "Audio line out Lime"
The black jack with another Audio Out icon is "Line Out 2" described
by Creative Labs.
The orange jack with another Audio Out icon is "Line Out 3" described
by Creative Labs.
Line Out 2 and Line Out 3 apparently belong to 7.1 or 6.1
multi-channel systems and maybe are not excited by the Linux
installation speaker test.
Nothing tells me whether any of these jacks should be used with
low-impedance speakers or if they are supposed to be Line Out. The
Creative Labs page is very specific about wanting amplified speakers.
I now know much more than I thought I would want to. But I don't know
much about line levels or source and load impedances, which bothers me
some, since I have been dabbling in audio engineering since about
1953. I would have expected to find more information in the 17 pages
of Chapter 17: Audio Components. I learn the maximum output voltage
of LineOut and the frequency response, but nothing about the
conditions under which it is to be measured..
I suppose I could resurrect some of my audio-frequency test equipment
and do some experiments.
carl
--
carl lowenstein marine physical lab u.c. san diego
[EMAIL PROTECTED]
--
[email protected]
http://www.kernel-panic.org/cgi-bin/mailman/listinfo/kplug-newbie
