EAX output to a Dolby Digital Reciever

I read on a different thread that a mono headphone plug to coax
adapter
connected from the digital/analog output of the SB Live! to a coaxial
digital input on a Dolby Digital receiver will give Pro Logic output
in EAX games. Does anyone know if: a.) this is true b.) this will
work with my setup c.)this will work with the digital/analog output on
my SB PCI128?
Thanks for the help,
-Hukuis

(hukuis) writes:

I read on a different thread that a mono headphone plug to coax
adapter
connected from the digital/analog output of the SB Live! to a coaxial
digital input on a Dolby Digital receiver will give Pro Logic output
in EAX games. Does anyone know if: a.) this is true b.) this will
work with my setup c.)this will work with the digital/analog output on
my SB PCI128?

Pro Logic decoders "work" on stereo sources that aren't surround encoded
in the sense they will give an effect based on the happenstantial differences
between the channels, so that by getting activity from the center/surround
speakers, you may feel you've got more surround than stereo from just the
front l/r speakers.

However, the 3D Positional Audio part of EAX is computing specific signals
for those 2 speakers, or more signals depending on the speaker settings,
so you will either degrade what those computations are attempting, or you
will do that plus have missing channels going into the process.

-Dave

the 3D Positional Audio part of EAX is computing specific signals
for those 2 speakers, or more signals depending on the speaker settings,
so you will either degrade what those computations are attempting, or you
will do that plus have missing channels going into the process.

-Dave

If I configure my soundcard to use 4 speaker mode with digital output
(through the digital/analog output), will I get 4 speaker EAX? I read
somewhere that this can be done, but I won't get discreet rear
channels. Is this true? And once again, will this work through my SB
PCI128? Is the degredation you hear noticeable, or only if you know
what you're looking for and are listening carefully?
Thanks for the help,
-Hukuis

(hukuis) writes:

the 3D Positional Audio part of EAX is computing specific signals
for those 2 speakers, or more signals depending on the speaker settings,
so you will either degrade what those computations are attempting, or you
will do that plus have missing channels going into the process.

If I configure my soundcard to use 4 speaker mode with digital output
(through the digital/analog output), will I get 4 speaker EAX?

In that case, if you attach to a DD decoder input, you will get the
front 2 channels of 4 speaker EAX and the rear 2 channels will be
produced but you won't hear them because they aren't connected.

I read somewhere that this can be done, but I won't get discreet rear
channels. Is this true?

It's not true. It sounds like a confusion of LiveSurround and the way
the Cambridge Soundworks (CL) DTT2500 speakers accept digital 4-channel
as 2 separate SPDIF signals.

And once again, will this work through my SB PCI128?

The PCI128 doesn't have a digital jack.

Is the degredation you hear noticeable, or only if you know
what you're looking for and are listening carefully?

I don't know. I've never heard EAX on an incorrectly connected and
misconfigured setup. In theory, it's contrary to the mechanisms 3D
positional audio is based on.

-Dave

I read somewhere that this can be done, but I won't get discreet rear
channels. Is this true?

It's not true. It sounds like a confusion of LiveSurround and the way
the Cambridge Soundworks (CL) DTT2500 speakers accept digital 4-channel
as 2 separate SPDIF signals.
Thanks for clearing that up.

The PCI128 doesn't have a digital jack.
I have an OEM version of the PCI128 that does have an analog/digital
jack.
I have heard of other people who have the same OEM version, and Harvey
Fong from Creative Labs has confirmed that such an OEM card existed at
one point.

The last thing i really want to know is if Pro Logic upmixing really
degrades sound quality that much, regardless of whether the signal is
EAX or not.
Thanks,
-Hukuis

(hukuis) writes:

The PCI128 doesn't have a digital jack.
I have an OEM version of the PCI128 that does have an analog/digital
jack.
I have heard of other people who have the same OEM version, and Harvey
Fong from Creative Labs has confirmed that such an OEM card existed at
one point.

The question, then, is what it really is. I think it's probably designed
to hook to OEM speakers that have a decoder and need a front-channel
digital in to support it. I'm aware of speakers like that that also have
a rear analog in, so they would really be a half digital, half analog,
4-channel speaker system to be configured as a 4-speaker system, which
happens to also be able to play prerecorded DD. As such, I think it
would not intend that you only connect the digital output, or that you
be satisfied with 2-speaker EAX. I think it's probably not a digital
out that supports Digital-DIN connections.

AFAIK, EAX on any sort of PCI128 would be software only and more primitive
than the SBLive-/SBAudigy-series versions.

The last thing i really want to know is if Pro Logic upmixing really
degrades sound quality that much, regardless of whether the signal is
EAX or not.

As I said, I don't really know. It's not that it would degrade "sound
quality" so much as a concern about degrading the 3D positioning. 3D
isn't a simple panning concept; it's about computing what your ears would
hear if the sounds were where they're supposed to be coming from and what
needs to come out of the speakers where they actually are to produce the
same sound at your eardrums. In includes such concepts as the right
speaker including sounds that cancel what your right ear should not be
picking up from the from the other speakers. On non-EAX sounds, Pro
Logic is designed to decode Dolby (not Digital) Surround, but does have
a sort-of-spatializing effect on straight stereo. Pseudo-surround has
its place, and personal likes/dislikes have a legitimate role in all this.

Personally, I'm the sort who would be bothered by knowing I'm listening
to a pseudo-something and have a tendency to want to listen to a stereo
recording in the manner it was designed to work. But, that's just me.

-Dave