Analog Audio Output Jack for Digital Speakers with same jack configuration

The Mac Pro has an analog out jack and a digital optical out jack. You can't get digital out from the 3.5 mm mini-plug.

Do you want digital or analog? Your question seems to imply that you have speakers that accept a digital signal but you also say you want analog...??

Anyway, my Mac Pro (2006 model) has separate analog and optical digital outputs on the back. The pictures on the apple website still show the same thing on the Mac Pro so I'm guessing it's the same. I think only the Mac laptops have the analog/optical digital combo jacks...

The optical digital outputs are the little white squarish ports beneath the rear firewire ports.

The MacPro does not have a SPDIF RCA style output. Maybe that is what you are thinking of from the windoze pc...

You should be able to enable the rear analog line output or the digital outputs from the System Preferences > Sound > Output screen. The front headphone outputs kind of act weird in that they disable the rear line output (if I remember correctly, I never use the front port...).

What is the model and brand on your speakers?

The Mac only outputs digital via the optical port.. not over a copper wire like you are suggesting..

I'm not sure about a converter ( i know about pro audio boxes that will convert between digital formats and stand alone A/D converters, but they are expensive.. I suspect it would be cheaper to replace your speakers...)

You're trying to do something fairly non-standard. Wired SP/DIF outputs are usually RCA type connectors, and your mac just has a TOSlink optical output. Since the BA speakers already have the surround sound decoder built in, something like this might work for you:
<http://www.tvcables.co.uk/cgi-bin/tvcables/AD102.html>

This should convert the coax digital output to a form you can use with your BA speakers.

Unfortunately, I do not think that this adapter will do anything for the OP. It only allows the use of a standard toslink(ADAT) cable with the minijack combo ports like those on a macbook. (or vice versa, I'm not sure) It does not convert optical digital to "wired" coax digital (SPDIF) ..

Here is a cheap device that just might work for you...

http://www.sweetwater.com/store/detail/Co2MAudio/

A Mac Pro has PCIe slots, so only PCIe cards will work. PCI sound cards will not work.

My first suspicion is that the Soundblaster is PCI..

And my second suspicion is that there are no MAC drivers for it. Soundblaster (Creative) cards have not been a Mac product at all, to my knowledge.

I'm curious why the MAudio format converter won't work?

I also have the same problem...the same type of speaker. I tried to ask Boston Accoustic's technical support and he said we should ask Apple's Technical Support about this. Here I quoted his statement:

... you can attempt to make these speakers work by contacting your computer manufacturer and asking them if and how to set your computer up to produce a digital audio signal. You want to tell them that you have a pair of BA 7500G CD Quality 16BIT/48KHz digital speakers and want to know how to set up a digital audio signal to talk with these speakers. With this information the computer people should be able to assist you in making this happen.

I hope people from Apple will help us to find the solution...thanks.

If you just need an optical converter to use a 3.5 mm optical plug with the TOSlink output, this will do:
<http://www.national-tech.com/specs/fiber-optic-adaptor/30f2-79902.htm>

If you actually need to convert optical to copper you'll need something more elaborate. Those converters are readily available for under $ 200.

I also have the same exact problem. Were you able to contact Apple and get an answer...
I can't figure out how to configure the sound settings to meet the digital 16 Bit / 48 Khz
Let me know if you found out how to do this?