Pro-Logic I/II/IIx matrixed output from 5/6/7.1 soundcards

[Jiggly]

I thought I'd post a question here since this forum is FILLED with people who appreciate all the various audio formats, and why it's not always cool to upmix old soundtracks.. I am wondering if it is possible to decode and playback TRUE matrixed Dolby Pro-Logic sound from stereo tracks on a 5.1/6.1/7.1 soundcard without a Pro-Logic decoder.

(I found some answers and posted them a few messages down if you're looking for the same info.. This applies to ANY multi-channel soundcard, not just the Audigy 2. Meanwhile I shall leave the rest of this thread intact for future historians!)

The Audigy 2 has a mode to switch to 2 speaker stereo output, which is fine if you have an external decoder, but I have "dumb" 5.1 speakers with no decoder. Turning off the "CMSS/Virtual 5.1" features, even with the output set for 5.1 speaker mode drops all pro-logic/stereo mixes to the Front L/R channels only.

"CMSS" is murder to sound localization, and it improperly remixes the 4 pro-logic/2 ch. stereo channels all over the 5 speakers. This results in a (loud) center channel mix coming from the rears and Front L/R speakers, and almost no sound from the actual center speaker itself. I don't like it. I can't fix it!!

I'm fearing that the answer is NO.. You can't have old fashioned Pro-Logic without an external decoder, but one can only hope..

ALSO, can Audigy 2 do Pro-Logic II? That was a little better than CMSS. Audigy 1 had it, but it's not on the latest Audigy 2 cards. I've seen references to Pro-Logic II in the Audio HQ panel on some web sites, but it must be from older drivers.

Does anyone know if the Santa Cruz 5.1 card does old Pro-Logic? I have one somewhere getting dusty..

Riche

[Dragonsf]

Have you tried AC3Filter?This driver let's you define your output in a matrix, where you can combine any input channel to any output channel.

[Jiggly]

Thanks for the tip, I'm playing around with AC3Filter.

If anyone is curious, since I saw a lot of people checked this post out-- I did more research and found several plugins to do the Pro-Logic to 5.1 upmixing. There is a free plugin called "Dee3" that works through WinAMP 2/5. I tried the KB5.1 plugin and it didn't work. Someone else posted that KB5.1 doesn't work with the Audigy 2. There is also the "Circle Surround II" plugin by SRS Labs for WMP9 ($14.99 US)and ""MatrixMixer", which is free (Based on AC3Filter).

I played around with the settings and found that this is the closest thing I can get (other than using a third-party software decoder) to making the Audigy 2 output something like Pro-Logic/Pro-Logic II:



You have to drag the center channel bar up at the very end, after making the other adjustments. Otherwise it will automatically balance itself with the L/R speakers, and basically will become inaudible.

(I'm still looking, if anyone knows any registry settings or anything else to get the card itself to decode Pro-Logic without blending the channels)

[Jiggly]

THIS IS NOT AUDIGY SPECIFIC !!! This information also applies to most 5/6/7.1 soundcards without native Pro-Logic I/II/IIx decoding & upmixing capabilities.

AKA How to avoid cheesy "Virtual 5.1" and CMSS-style soundfield mangling when you want something more than just Stereo.

A reply to my own message! Knowledge for those who still have not found the answer..

I've been trying to find a way to get good TRUE discreet Pro-Logic output from a 5.1/6.1/7.1 soundcard without support for standard Dolby Surround/Pro-Logic. Not every DVD has a 5.1 track, and if you still have Hi-Fi VHS tapes or pre-AC3 laserdiscs, you need a Pro-Logic decoder to upmix or else you only get plain old stereo from the front Left and Right speakers.

To get "discreet" active matrixed pro logic style 4/5 channel output from a 5.1 card like the Audigy, which uses CMSS (C.reative M.atrixed S.tereo SUCKS) at upmixing stereo to 5.1, these are the highest quality options:

DISCREET:

SRS CSII Circle Surround Plug-in (WMP9 very good for MP3 & DivX)
WinDVD 5 for DVD/Mpeg

Use SRS CSII Circle Surround to get upmixed Pro-Logic-like results from Media Player 9. This filter SEEMS to be using the "Adaptive Matrix" decoding method mentioned on the Dolby website, and has no signal leakage between any of the four channels as a result. So in other words, if you drop the center channel to 0, it pretty much disappears from the mix. Unfortunately for the purists you can only use this one with Windows Media Player, and if you're NOT living off loans and grants it's also 15 bucks to register it, which is like 6 days worth of ramen, so you decide what's more important.

Use WinDVD 5 or above to get great Pro-Logic II upmixes for 2-channel DVD soundtracks or Mpegs.

NOT DISCREET:

Matrixmixer (DirectShow)
AC3Filter (DirectShow)
Blade DolbyMP Encoder (WinAMP)
Wave 5point1 Output (WinAMP)
KB 5 Channels Output (WinAMP)
Dee3 (WinAMP)

Most X.1 cards (if not all of them) ignore the Center/L/R Pro-Logic information, and artificially widen the surround channel all over the place for their proprietary "Virtual" X.1 surround modes. Not that I mind widening the surround channel, which is mono anyway, but the problem is usually the center channel information is also coming out of every speaker, including the rears. This results in poor or no directional audio, and an unnaturally wide "everything is coming from every speaker" sound. Most of the time it sounds decent with music, but it ruins a lot of movies.

Every filter I tested save for the SRS filter upmixes to X.1 using the passive decoding method. So in any of these filters, volume and phase differences are used to determine where sound should go, and no other filtering or mixing is done to remove unwanted sound from inappropriate channels. Passive Pro-Logic is basically just glorified stereo. The left and right speakers are standard unmodified stereo output. The center channel is a mono combination of the left and right. The surround channel is a left/right phase-inverted mono signal which is amplified and delayed before playing from the rear speakers. The surround channel is the only discreet channel not containing sound from the other three, however it can still be heard from the front three speakers, only it's much quieter than the other sound levels.

You can hear the surround channel on any home stereo by plugging a speaker into the +R and +L outputs (though that's not necessarily a GOOD idea), and on some amps and portable players you can carefully pull a pair of stereo headphones partway out and get the same effect.

In active Pro-Logic decoding, the channels are mixed the same as passive decoding, but additional filtering is done after the volume/phase mixing to clean up the four channels. So active decoding also removes center sound from the front left and right speakers, removes front left and right speaker sound from the center channel, and removes the surround channel from the front three. So none of the speakers are actually playing the original stereo mix or sharing data, they're all getting a discreet altered mix.

[url]http://www.dolby.com/tech/whtppr.html]Dolby Pro-Logic Explained (By Dolby)/url]

AC3Filter and Matrixmixer use passive pro-logic decoding, so the upmixed channels are localized. However when I muted individual channels and still heard other channels coming out of the wrong speakers, it was obvious it was NOT a discreet mix. Wave 5point1 Output, KB 5 Channels Output, and Dee3 plug-ins were all the same passive style upmixers.

The Audigy 2 card itself? CMSS! CMSS SUCKS. Creative needs to forget it and go back to real Pro-Logic II or IIx..

Funny thing--some of the Creative speaker sets do their own discreet 2 to 5/6/7.1 upmixing. Kind of steers you toward having to purchase Creative branded speaker sets now that they've dropped discreet upmixing from their soundcards..