DPLII Upmixing OR Ambisonics?

[joshbm]

I've been doing some thinking... Which would be better from a stereo source to a 5.1:

> Upmixing it using Dolby Prologic II methods
> Upmixing it using Ambsonics (Bidule etc)

I currently am leaning more towards Dolby Prologic II. I like the different discrete sounds in each speaker.

Opinions welcomed!
-joshbm

[Eye of Horus]

blabla

[ursamtl]

Hi josh,

Probably the best would be to try each and see what sounds best to you. If you prefer the sound pf DPLII, go for it. It's certainly an improvement over Dolby Surround (which had mono surrounds).

In an email exchange I had with Angelo Farina a few weeks ago, he rated Pro Logic II much higher than Ambisonics when it's used on a regular commercial stereo recording. In other words, Ambisonics works best on material that's recorded using certain specific miking techniques, etc. When Ambisonics is applied to regular stereo sources, the results are basically harmonics generated by combining L+R (for the X signal) and subtracting L-R (for the Y signal). The original Dolby Surround basically just took the equivalent of the Y signal and routed it to the rears, rolled off the high frequencies and applied a delay. Depending on the decoding layout you use, Ambisonics does a much more sophisticated job of distributing the X and Y signals. How this compares technically to DPLII is hard to tell because the Dolby steering technology is not readily available on the net.

It also depends on which Ambisonics you use. Although some have had good results with the original guide on here, I was never pleased with its sound and found DPLII far better. If you want better results (again, to my ears) using VSTs, try applying an instance of the Panorama plugin to each stereo channel then routing it through one of the Emigrator speaker layouts. If you don't care about VSTs, and just want to open a bidule and process sounds, try my V.I bidule (http://forum.doom9.org/showthread.php?s=&threadid=79862). In it, I implemented Ambisonic formulas from various sources on the net and I was pleased with the results. I'm currently finishing work on an expanded verion of V.I that implements a couple of new things I read while on vacation. The tests I've done on this have been quite encouraging. To my ears, it sounds quite nice.

You might also want to try kempfand's Gerzon 1997 bidules. These also provide good surround mixes.

In the end, it all comes down to what sounds best to you. You're the one who's going to be listening to them. Just remember the pointers that seem to come up all the time in these threads. Start with a nice, clean CD rip by using Exact Audio Copy or CDex to rip the files. Do not normalize or change the file in any way while ripping.
If you have a program that removes DC offset from your file, be sure to use it before upmixing. This maximizes the dynamic range of your file. Check www.analogx.com for more info and a DX plugin. You can find a free rack that will load DX plugins in bidule at http://vincent.burel.free.fr/download/ffx4_FullDemo2.zip (corrected from original incorrect reference to SpinAudio)
If you're not using bidule, convert your files to 32 bits first (bidule does this automatically).
If you're going to reduce the files to 16 bits, it's best to use some sort of dithering. If you're using Surcode, it accepts 32-bit files, but it's unclear whether the program dithers the files or just discards the extra bits (which is bad!)

Enjoy!
Steve.

Originally posted by joshbm
I've been doing some thinking... Which would be better from a stereo source to a 5.1:

> Upmixing it using Dolby Prologic II methods
> Upmixing it using Ambsonics (Bidule etc)

I currently am leaning more towards Dolby Prologic II. I like the different discrete sounds in each speaker.

Opinions welcomed!
-joshbm

[ursamtl]

Originally posted by Eye of Horus
You won't get discrete sound from ALL speakers when using DPL II.
The rears are mono !

Sorry EoH but the this isn't entirely true for DPLII. It is true for the original Dolby Surround, but DPLII implements technologies that provide two separate outputs. For instance, Panorama mode, which wraps the front soundstage to the side. It's actually somewhat similar to kempfand's Gerzon 1997 bidules.

If someone just takes the front channels, subtracts one from the other and sends it to both rears, then it's mono. Even if there are two separate streams, they still contain the same data. I was doing this in my dorm room and in my car with two speakers fed the difference signal from my stereo and controlled by a cheapie Radio Shack volume control back in the 70s!

However, what I like about DPLII is that they steer some other data independantly to each rear speaker as required. For more info, check
http://www.dolby.com/Consumer/Technologies/PLII/PLIIwhtppr.html

Unfortunately, the specifics for how the steering is done are vague. Ambisonics info is available all over the net, but Dolby guards their formulas quite well. They provide just enough technical info to tease us, but not to give us everything! ;)

Regards,
Steve.

[Eye of Horus]

blabla

[ursamtl]

Originally posted by kempfand
Steve,

I must be blind ... found the wrapper to pack a VST and make it accessible under DX, but not the other way round.

Can you please point me to the exact link or page ?

Regards,

Andreas

Hi Andreas,

No you're not blind, but my memory is faulty (too bad we humans couldn't just install a couple of new DIMMs :) )

The rack is actually at: http://vincent.burel.free.fr/download/ffx4_FullDemo2.zip. I've gone back and corrected this in my original post.

I've read a couple of people say they've found this plugin a bit flaky, but I've used it on several occasions without problems. It's great to be able to use DX plugins in bidule. some of the Hyperprism, Izotope, and AnalogX ones do some interesting stuff.

Steve.

[ursamtl]

Originally posted by Eye of Horus
Yes, Ursamtl, you are right. I mixed up the old Dolby surround...
But still : if you have a DPL II setting on the receiver, it's kinda useless to convert to DPL II, don't you think ?

Indeed! The only reason I can think of is if someone has a receiver that does 5.1 but doesn't have DPLII but rather the original Pro Logic. I don't know how common this would be. According to Dolby's own papers, DPLI was not designed for playing back regular stereo music with no matrixed surround information, whereas DPLII is. Of course then one could debate whether the ambience information present in the difference signal of most stereo recordings qualifies as surround info. Most traditional "pseudo-surround" methods just take this and send it to the rears. They're not very sophisticated, but they sound good on many recordings.

Originally posted by Eye of Horus
BTW :

"If you're not using bidule, convert your files to 32 bits first (bidule does this automatically)."

That's not correct. Bidule works internally with 32 bits routines. But a 16 bits file will not be converted. It is only processed with the internal 32 bits routines .....
There are programmes that work internally with 64 bits : same situation.
You really should do the conversion to 32 bits floating first....

EoH

Actually, davidv@plogue wrote that Bidule's Audio File Player converts 16-bit files to 32-bit (see
http://forum.doom9.org/showthread.php?s=&postid=514525#post514525). You're right for most programs, but since David is one of the people who wrote Bidule, I'm sure we can all take him at his word.:)

Cheers,
Steve.

[Eye of Horus]

blabla

[ursamtl]

Originally posted by Eye of Horus
I just read it and will contact David to discuss this with him....
( have some other things in the pipeline too....)

I read once another post from him here , in which this wasn't clear. He told about the internal use of 32 bits but didn't mention converting by the program at the point the file leaves the fileplayer !!

thanks for the info !

EoH

I've contacted David and received the following answer:

from davidv@plogue in a private message on the Plogue forum
Hello Steve.

All processing inside bidule is in 32 bit float, so yes we convert from 16 -> 32 bits directly in the AudioFile player module (before leaving it).

I guess this resolves the question. It's nice to know we don't have to convert to 32 bits externally before loading files. He also mentioned that bidule does not dither but simply truncates when reducing to 16-bit files, so dithering should be used.

Regards,
Steve.

[Chainmax]

Which one of these two methods would you guys use in order to transform a stereo soundtrack from an analog capture to 5.1?

[ursamtl]

Originally posted by Chainmax
Which one of these two methods would you guys use in order to transform a stereo soundtrack from an analog capture to 5.1?

Personally I prefer the V.I method at http://forum.doom9.org/showthread.php?s=&threadid=79862. I get good results from it and I've received a great deal of positive feedback about it. I've found that it provides better separation and a smoother sound than any of the Ambisonic methods using plugins.

As for DPLII, well what's the point? Almost all 5.1 receivers have it built in, so it's much easier to just play your two-channel audio and then hit the switch! DPLII is good, but for non-Dolby encoded audio, if you really dig into the technical details, it's really not much better than the original Dolby Surround.

Regards,
Steve.

[Eye of Horus]

blabla

[ursamtl]

EoH,

It's curious that you should react so strongly by writing such a statement as "I can understand you're constant advertizing your own method." Sounds kinda junior high, or Alexis Carrington to me! You recently complained that you found the climate in this forum unpleasant, but to be frank, I find this kind of comment quite unpleasant as well. It's offensive to the spirit of cooperation we try to foster in public forums.

If someone asks for recommendations, simple logic dictates that I give them the one that works best for me, which right now is V.I. It's not some sort of commercial endeavor I make money from, so obviously I'm not gaining anything from it. I'm not about to start putting links to Paypal in my posts or try and impress people by talking endlessly about long hours of hard work.... I've simply posted it and said, "it works well for me, give it a try and see what you think."

Out of all the feedback on V.I that I received, no one complained about sound coloration. Out of all the comments I've received, one mentioned that it would be nice to remove vocals from the rears, another thought the LFE was weaker, a third felt the rear levels were too low, and a fourth wanted an even wider soundstage. Other than that, all comments have been very positive and encouraging. Some friends and I are currently doing professional testing on a new version of V.I that will address some of these recommendations and throw in a couple of other things. When it's ready, I'll post it with appropriate instructions and let those who try it decide.

If I was into some sort of self-promotion trip as you imply, I would not recommend other methods. I've also repeatedly recommended kempfand's Gerzon 1997 methods and recently Kpex's original Upmix method. If I don't recommend other methods that I've tried, it's because they didn't produce results I could recommend. Some were not bad, reflecting interesting approaches to the art. Some others sounded like pure schlock to me. If one tries to combine aart with schlock, the results are predictable.

[ursamtl]

Originally posted by Eye of Horus
Give people the link to ALL methods, not only to your own.
I remind you that it was my idea to create the list of all methods at
http://forum.doom9.org/showthread.php?s=&threadid=79774. All the other readers of this forum have to do is go back and read the debate on this and see how you opposed it and then finally admitted it was a good idea.

If someone asks me which method I would recommend, I'm obviously going to tell them what works best for me and for the people who've told me how much they like V.I. If someone says they're looking for methods in general, I'll send them to the list. If kpex recommends his method and I agree that it gives good results, I'll say so, as I did last week.

EoH, it's obvious that you and I are not going to agree on anything, so for the sake of this forum, let's end this discussion now.

As you so often say, "Plonk!"

[Chainmax]

Originally posted by ursamtl
Personally I prefer the V.I method at http://forum.doom9.org/showthread.php?s=&threadid=79862. I get good results from it and I've received a great deal of positive feedback about it. I've found that it provides better separation and a smoother sound than any of the Ambisonic methods using plugins.

As for DPLII, well what's the point? Almost all 5.1 receivers have it built in, so it's much easier to just play your two-channel audio and then hit the switch! DPLII is good, but for non-Dolby encoded audio, if you really dig into the technical details, it's really not much better than the original Dolby Surround.

Regards,
Steve.
Your method relies on some pretty complicated setup like EoH's Ambisonic's guide. What I want (as I stated on my thread) is a simple way to produce satisfactory 5.1 out of the common stereo track you get from an analog capture. Now, I see you replied in that thread that for non-Dolby encoded audio DPLI is pretty much the same as DPLII and that all 5.1 receivers have a DPLI or II switch. So, why even bother transforming stereo to surround at all?

[ursamtl]

Originally posted by Chainmax
Your method relies on some pretty complicated setup like EoH's Ambisonic's guide. What I want (as I stated on my thread) is a simple way to produce satisfactory 5.1 out of the common stereo track you get from an analog capture. Now, I see you replied in that thread that for non-Dolby encoded audio DPLI is pretty much the same as DPLII and that all 5.1 receivers have a DPLI or II switch. So, why even bother transforming stereo to surround at all? Good question. I started doing it because I've never been that impressed with Pro Logic I or II. The surround effect they produce has always seemed weak in comparison to the big sense of space I hear in commercial 5.1 soundtracks and some 5.1 music mixes. They work fairly well for encoded movie soundtracks, but for regular two-channel stereo, they don't impress me. After lots of experimentation I came up with something that gives me the results I want. I shared it with others, just as many others in the forum have done when they discovered something that sounded good to them. What does mine do for me that DPL doesn't? For many recordings I've tried, it gives the instruments more space and definition. Here's a description of some test results I posted recently: http://forum.doom9.org/showthread.php?s=&postid=536560#post536560

So, as you can see from what I wrote there, it's because of the music. I'm not trying to sell this to anyone or make any money. I do this for my own fun and collection and I hope others do the same. I haven't set up some private distribution network for upmixed versions of copyrighted music. I simply like hearing my favorite music in three dimensional sound instead of 2D.

As for the setup, it doesn't really have to be that complicated. Using the bidule method is actually much less complicated than hacking WinDVD DS filters with hex editors, etc. If you check the mini-guide I wrote, you'll find that all the steps necessary are there to produce the 6-channel wave file. This is as far as the DPLII guide take you. Basically, you download a couple of programs, install them, open the files, and away you go!

If you do check out V.I and your computer is equipped with 5.1 speakers and soundcard, try right-clicking on the box in the middle called "V.I" and switching the Processing Mode menu item to "Bypass." This switches the effect off and gives you the original two-channel stereo input. Then switch the Processing Mode menu item back to "Processing." As you switch back and forth, you'll hear the soundfield grow and shrink. The fronts will sound pretty much the same, but the overall sense of ambience truly does expand and contract quite naturally.

Of course, as I said, if all you want is DPLII, just burn your capture to a stereo audio CD, pop it in your surround system, switch on the DPLII and take the time you saved and enjoy the recording as is. :)

[joshbm]

@ EoH and Ursamtl:

The topic of the thread is DPLII Upmixing OR Ambisonics. Not the Tom and Jerry Show. Or Jerry Springer at that. Please, for the sake of the forum take your insults/bickering elsewhere. This kind of talk is extremely helpful for new people in the forum <sarcasm>.

If something is not worth reading than why write it? I would ask a moderator to be the bigger person here and take charge of a situation gone out of control. I know after this comment is written 4 things may happen:

1.) A Moderator will intervene and prevent further attacking/ bickering about useless information irrelevant to the topic thread.

2.) One or both people will attack me verbally, which I do not mind since I will not be posting to this thread again.

3.) You guys appologize and stop, which a moderator will not have to get involved and seperate you two siblings, and both of you can learn from your mistakes.

4.) This will start a big fight over each other's ego and sense of pride here in the forums.

I hope that the 3rd choice is the road actually taken, but really... think back to why fight in the first place? Is it really *that* important to both of you to keep your pride, or can we move on to a more useful thread.

Thank You and Goodbye,
- Joshbm

[ursamtl]

If you go back and read from the beginning of the thread, I think you'll find your answers as to why.

[Eye of Horus]

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[Eye of Horus]

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[KpeX]

ursamtl and Eye of Horus:

Please, please try to keep your comments civil. Obviously nearly every author of a 5.1 method will recommend his own method, since it is written to optimize his preferences. Recommending one method over with logical reasons makes for good discussion (and is not !! an insult), but childish bickering and insults are harmful to scientific discussion and forum morale. I must admit I wasn't keeping a close eye on this thread until now. However, the next person that argues a 5.1 method with an insult rather than a logical argument is begging for a rule #4 strike.

I would prefer to keep this thread going, since at one point there were some good posts on audio conversions. Please return to such posts.

[ursamtl]

kpex,

Thanks for intervening. You're right, people will obviously tend to recommend something that works well for them.