digital output question

titoafric

I currently have an Audigy (SB0090 a400) and I'm feeding the digital output to an external DAC. When I first attempted this I found that I could hear only the rear output through the DAC and was confused for a while.

I have since read the extremely useful kX newbie guide and was able to see what was going on with the output: the DAC was apparently working with the digital rear instead of the digital front (which I was expecting).

Does anyone know whether there is something in kX that's causing this that I should learn about or if that's just the part of the output that the DAC is going to use regardless of what I do? Thanks.

dj_stick

uncheck the swap/front rear option in kX

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titoafric

Hmmm.. it looks like I need to understand more about how this device is taking the digital output.
It looks like it'll only convert to analog if the front and rear digital output is exactly the same: if I alter the front or rear just slightly with a 10 Band EQ, I simply get noise.
This means that the swap front/rear option isn't taking effect since both are going to be from the same source. But it sort of answers my questions.. It was the identical front and rear digital output that affected my final analog output.

Edit: Actually, I was wrong. It seems I had toggled the "S/PDIF Bypass" by accident and did not notice. With it on, I am able to change the front and rear as I wish, but only the rear affects what I hear, even if the swap front/rear is toggled. So, I remain confused...

Russ

Can you provide more detail about what you are doing?

i.e.
How many external DAC's are you using?

You will only get one (stereo) channel per DAC, unless you are decoding AC3.

Where are you taking the signal from?

See this picture, for the pinout of the digital out jack.

titoafric

Sorry about the lack of information. I'm attempting to connect the digital out to a single DAC.
Based on that picture, my 3 pole connector is taking the front and rear portions of the digital output. I'm now wondering why my DAC looks at the rear channels instead of the front when I simply use an adapter to go from 3.5mm to coax.

I also have no idea what S/PDIF Bypass does. When doing the above, the front and rear channels must be identical except when S/PDIF bypass is toggled on.
When I split the 3.5mm jack into two RCA, the left plays the front digital output and the right plays the rear digital output. The left only works when S/PDIF bypass is not toggled on, but the right works regardless.
My question seems to have completely left the DSP arena and now I'm just asking for a lesson in how these things work.
Thanks in advance.

Maddogg6

As per DJ Sticks Getting Started guide (KX Mixer)

Russ

I think SPDIF Bypass is used for bypassing the DSP for digital input (i.e. digital input is routed directly to digital out (no resampling, etc)). It probably uses SPDIF 0 for this, which is probbaly why you lose the front signal when it is enabled.

That sounds right (i.e. how it should work).

ROBSCIX

RUSS, I thought the audigys only output stereo out of the SPDIF. This is why Tril made the enocder. SO I really dont understand your jack diagram. I htought using those 3.5mm cables one RCA would be input and the other would be output for SPDIF ?.
So your saying you can get digital surround out of a audigy?

Russ

The reason for redocneXk is because most digital receivers have only a single SPDIF input, thus the only way to get multi-channel (> 2) audio, over a single SPDIF connection to a receiver, is using compression (AC3, etc).

The digital out jack on some models (not sure about all models), actually has 3 seperate SPDIF outputs, and when used with a compatible speaker system, can output multi-channel audio (3 seperate PCM streams) using all 3 outputs.

http://forums.creative.com/creativel...ssage.id=12170

BTW: I do seem to recall that some models (i.e. Audigy 4) use the digital jack (referred to as digital I/O instead of digital out) for both input and output (with the Creative® Digital I/O Module), and as such, probably uses a different pinout. Refer to the documentation that came with your card for information about the digital jack on your card. I am pretty sure that the OP's card (SB0090), uses the above pinout. Obviously, if your card has only a single SPDIF output, then compression is your only choice for multi-channel audio using the digital connection.

ROBSCIX

Well right now I am using a 3.5 mm to twin RCA jacks to get a SPDIF signal out of my Audigy and it works fine. I am pretty sure the input works aswell I tested it I think...Does this make sense or do I just have a output and no input becasue of the cable.

Upon review of your diagram I should really have two SPDIF outs. one on the one RCA and one on the other as I have a audigy 2. So how can I test this out?

Russ

I am not sure of the pinout that your card uses (iirc, you have the A2 Value).

The Creative® Digital I/O Module works with the following models:

• Sound Blaster Live! 24-bit
• Sound Blaster Audigy Value/SE
• Sound Blaster Audigy 2 Value
• Sound Blaster Audigy 4
• Sound Blaster X-Fi XtremeMusic
• Sound Blaster X-Fi Platinum
• Sound Blaster X-Fi Fatal1ty
• Sound Blaster X-Fi Elite Pro

So, if your card is one of the above, then the pinout is probably different (although the tip is probably still SPDIF 0 out).

ROBSCIX

So your thinking that using that cable with my card probably give me output on one side and input on the other? that is what I figured and I will be testing it out later.

Russ

Yes, but it depends on what the pinout is, as to whether your adapter will give you input on one side and output on the other (i.e. if the input is the inner-most ring or the sleeve, then you will not get any input from your adapter). In any case, it should be easy enough to test.

Maddogg6

On the A2ZS - the rear digital jack is called 'Digital OUT' for me - as all the SPDIF IN's are on the board (Digital CD IN and the AD_EXT or AUD_EXT - however its called)

@ROBSCIX:
If you look very closely at the pic russ linked to - its a 4 connection plug - instead of the typical 3 . This is a 'special' cable commonly found with camcorders to have video plus L&R analog plus gnd. - It also happens to be the same type used for my cards analog outs for access to the additional 2 outs needed to get 7.1.

So unless you get one of these special cables - and your card is in fact one on the list - your gonna loose access to one of the connections - and I have no clue what that lost connection equates to (spdif in, one of the other outs??)

Its also possible now that you are 'shorting' out one of the connections if your using the typical 3 connector plug (3.5mm to RCA - like a headphone to RCA Line in adaptor) - and that may cause a problem ???

edit: unless this 4th connection is something that tells the soundcard that there is someting plugged into that jack - sort of like how a live drive tells the card its available??? - cuz I only see 3 'needed' connections for 1 spdif in and 1 spdif out (plus gnd) this additional IO mudule offers. (as the optical and coaxial spdifs looks like and are most likely paralleled and not discrete.)

Russ

Exactly, if for example the 2nd ring is input, and the sleeve is a ground (or vice-versa), then using that adapter would have the input shorted directly to ground, and thus the adapter would not give any input.

BTW: It shouldn't cause any problems, you just would not get any input under that scenario.

ROBSCIX

Well I have digital out. I will test for digital in and let you know. I don't want to wreck anything but it all seems to be working fine...Where could I get one of these cables?

Russ

It should not hurt anything, and if the 2nd ring and sleeve are both grounds, then your adapter is fine.

As for the cable, the only one I could locate that has the correct pinout, is the Apple iBook A/V cable. Digital camcorders have similair cables (available at any Radio Shack, etc), but none of the one's I could find, use the correct pinout (for the Digital Out jack, again, I do not know what the pinout is for the Digital I/O jack).

If I were you, I would probably just buy the Creative® Digital I/O Module. It costs about the same (or less) as a decent cable, and you will not have to worry about the pinout, etc.

BTW: The pinouts for the other jacks (Line Out 1, 2 and 3) are in your manaul. Also, if you look in your manual, you will see that one of the recommended ways to connect to an external receiver is using a '3.50 mm (1/8-inch) mono-to-RCA cable', which also shorts together the same pins (as well as a 3rd), so you do not have to worry about your adapter hurting anything.

ROBSCIX

YEah I figured it's a digital signal anyway so what does it hurt puttin git to gnd? nothing.
I have Digital out, which is what I was after with this little experiment. I just tried to see if the card would allo digital input by using the other side of the cable and it wouldn't accept the digital signal. OK, now if that jack has two digital outs then where are the cvontrols for them? all I see is SPDIF in and out in the mixers...By the way I am using Creative drivers..has something to do with a project..SO if I had the correct cable I would have two digital outs? and two digital ins? I am using one of the 3.5 minijack to dual RCA plugs. Given the pinouts what would the other side be? just grounded out I suppose..

Russ

We do not know that it has 2 digital outputs (I suspect that it does not). What it (the module) does have, is two different connections for digital output, one for coaxial, and one for optical, both of which are probably driven from the same signal (i.e. they are not seperate independant outputs). I would guess that the inputs are also like this.

No, I suspect that you would have one output and one input, and the correct cable in this case, would be the Digital I/O Module.

That would be consistant with what I said above.

Again, I do not know the pinout, so I cannot answer that question (but, if you did not get a signal (in or out), then it is likely grounded).

ROBSCIX

I don't really care about digital input. I was just curious as to what the other guys said about having his fronts on one end of the conenctorand his rears on the other side of the connector in digital. or did I misunderstand something? or is this just when using digital output as I know creatvie speakers have a speacial cord..that one you posted I guess.

Russ

That is only with the Digital Out jack used on some models, and not the Digital I/O jack. My card (SB0228) is the same way (3 SPDIF outputs and Analog Center/LFE from that jack), just as it is shown in the pinout link I posted. It was intented to be used with the Creative 5.1 Digital speaker systems, but it is not limited to that.

ROBSCIX

I Have the SB400, the Audigy 2 Value so AFAIK the digital I/O module is fully compatible. It'a little hard to find so I have been told.
actually RUss, that digital I/O module is like $14.99 USD. I called Creative and tried to place a oreder but they don't ship to Canada but will be by the end of the month. I htink I want it now though so I am gonna call a shop and see if I can order it through them..for $15 why not?

Russ

Yup, that is what I was thinking...

ROBSCIX

Called a local dealer and they say $24 + tax, so still that's not too bad. Just not sure if I need the input that bad. I will think about it tonight. Might be good to have around. Thanx for the suggestions Russ.
Hey Russ have a look at this module, I am wondering if it would be compatible with a Audigy 2 I am not sure if mine has the AUD_EXT header and SPDIF header as I think they hook to.
http://www.audiencedp.com/sbdb3.htm

Russ

Yeah there are a few different addon modules/daughterboards (as well as the LiveDrive type stuff) available for some of the cards.

i.e.
Here is another one:
http://www.creative.com/products/pro...oduct=30&nav=1

I do not know a lot about them, but most seem to require the AUX_EXT connector or the SPDIF_EXT connector. I do not think your card has either one.

ROBSCIX

YEah I seen that one. COme to think of it your correct my board doesn't have any headers..bummer indeed. I still haven't decided if I am gonna get the digital I/O module yet but $27.60 is a good price though considering I will get coax and optical. It's just a questions if I need it or not. I may actually try and find a mono 3.5 to singal RCA as you said or just grab the module can never have too many audio inputs...thx for all your help.

Russ

I just used that as an example, to let you know that you were not hurting your card. Your adapter is fine (it works, right?).

Maddogg6

Is it possible were assuming the 2nd gnd on that connector is common with the 'normal' ground lug?

Im thinking thats why the inputs not working.. ?? a different gnd connection NOT common with the outputs. ?? I babble alot - I know.

Russ

As I said previously, I think that the SPDIF In, is probably on the second ring or the sleeve (and the other is a ground), and as such, the adapter is shorting it to ground, and that is why he is not getting any input.

i.e.
Tip - SPDIF Out
1st Ring - ground
2nd Ring - SPDIF In (or ground)
Sleeve - ground (or SPDIF In)

The last 2 above would be shorted together by the adapter, thus no input, but output works fine.

ROBSCIX

Do you guys think that module is worth $30? I am deciding as I would rather have both functions of the SPDIF, as you can never have to many inputs and outputs...