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Motherboard external speaker to SB16

dvanaria

Experienced Member
Joined
Apr 11, 2013
Messages
110
Location
Denver
I'm trying to hook my motherboard's external speaker jack up to my Sound Blaster 16 (CT1740) so I can play the PC speaker through the sound card.

My motherboard has a jumper for disabling the internal speaker (a buzzer). That is set to disabled to activate the external speaker 4-pin header. The manual says the pinout is:
pin 1 speaker
pin 2 key
pin 3 ground
pin 4 +5V

My SB card, however, has a 2-pin header for the speaker input. I believe its:
1 +5V
2 ground

How do you get 4 signals down to 2? I've never seen a cable that will do that anyway, I guess I'll just have to modify a CD-ROM cable (the that connected older CD-ROMs to the sound card, inside the case)?
 

Agent Orange

Veteran Member
Joined
Sep 24, 2008
Messages
6,071
Location
SE MI
I'm trying to hook my motherboard's external speaker jack up to my Sound Blaster 16 (CT1740) so I can play the PC speaker through the sound card.

My motherboard has a jumper for disabling the internal speaker (a buzzer). That is set to disabled to activate the external speaker 4-pin header. The manual says the pinout is:
pin 1 speaker
pin 2 key
pin 3 ground
pin 4 +5V

My SB card, however, has a 2-pin header for the speaker input. I believe its:
1 +5V
2 ground

How do you get 4 signals down to 2? I've never seen a cable that will do that anyway, I guess I'll just have to modify a CD-ROM cable (the that connected older CD-ROMs to the sound card, inside the case)?

It appears to connect through CN8. http://stason.org/TULARC/pc/sound-c...-card-SOUNDBLASTER-16-ASP-C.html#.UtsX0mco6ZM

Late edit:

You don't want to connect 5 volts to your sound card's external audio input at CN8. All you need are the audio and ground leads from your source. That external speaker 4-pin header that you mentioned above kind of reminds me of a CD-ROM power and audio setup. What motherboard are we talking about anyway?
 
Last edited:

dvanaria

Experienced Member
Joined
Apr 11, 2013
Messages
110
Location
Denver
That video clip from Mau1wurf1977 was perfect. I was on the right track actually, but I learned a few things completing this. I thought because the older Sound Blasters worked without any drivers being loaded (because a lot of the older games were programmed to access the hardware directly) that connecting the motherboard external speaker out to the sound blaster pc speaker in would also just work automatically. But it turns out (as I learned from the video) I still needed to install the SBBASIC disk - this has programs like MIXERSET which allow you to set the volume of the PC Speaker input, among other things.

I was confusing what that SBBASIC disk was - it's NOT the plug-and-play configuration manager software - this board wouldn't need the CTCM since it's not plug and play.

Anyway its working great now. With MIXERSET I can get sound blaster music and pc speaker sound at about the same levels, so I can just adjust my speakers once without worrying if one type of sound will be too quiet or loud.

Thanks for the help!
 

dvanaria

Experienced Member
Joined
Apr 11, 2013
Messages
110
Location
Denver
What motherboard are we talking about anyway?

I'm not sure the exact model number - the system is a Wang Alliance 750CD, a 386 25MHz system.

But I was able to get everything working by following the video sent by Mau1wurf1977.
 

Mau1wurf1977

Experienced Member
Joined
Aug 21, 2010
Messages
171
Happy to help dvanaria :)

Now your findings apply to many Sound Blaster cards, but not all! The old ones, that don't need PnP resource software and / or software initialisation, route through the PC speaker at all times! For example the Sound Blaster Pro 2. This is a card that allows you hear that POST beep when you turn off the PC. On later SB16 and AWE cards you won't hear it.

Be aware however, and I didn't fully know this when I produced the video, that that little cable (just like the CD-ROM audio cable) picks up a LOT of interference. It's that "hearing the computer thinking" sound if you have ever heard it. I usually mute all the inputs such as line, PC Speaker, CD and use an external mixer to control things on the fly. You can try this by sitting in DOS, maxing out your AMP / speakers and going through DOS directories.

Just something to be aware off :)
 
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