Is Soundstorm "Dolby Digital" output the SAME as a "Dolby Digital" DVD?

[dderidex]

I've read various gripes about the quality of nVidia's Soundstorm digital output, to include:
* Cutting off frequences over 17khz
* Cutting off frequences below 28hz
* Lossy compression algorithm

Now, my question is, doesn't DVD content use the same thing? I mean, a "Dolby Digital 5.1" AC-3 stream....is pretty much like any other "Dolby Digital 5.1" AC-3 stream, isn't it?

So those complaints are rather on the moot side? If I think DVDs sound fine with their DD5.1 encoding, so what if my games use the same encoding, right?

(FWIW, this question comes up because I'm dumping my GMX D-5.1 speakers for Klipsch Promedia 5.1 Ultras. Problem is that I have a Soundstorm motherboard, so must decide between buying an Audigy 2 and running the analog out directly to the speakers - and dealing with its increased CPU usage vs Soundstorm, it's 44khz to 48khz resampling on all audio sources, and the disabling of my front panel audio.....or to buy a Dolby Digital decoder and just run my Soundstorm optical out to that and run the speakers off the decoder.)

 

[dderidex]

Hmm...think I my question.

Turns out, the SoundStorm encodes Dolby Digital content at 640 kbps with no channel combination whereas DVD content is encoded at a variable bitrate of 64 kbps to 384 kbps and combines channels at high frequencies.

In other words, the SoundStorm output of sound from games is *higher quality* than the audio output from a DVD.

 

[DaveSimmons]

Not quite -- commercial DVDs don't use the same DICE encoder SoundStorm uses, and commercial DVDs don't chop audio at 17 KHz.

640 kbps seems like it would be better than 448 kbps, but that's assuming both encoders did exactly the same lossy compression and threw away the same "inaudible" sound to do it.

Anyone who has compared first-generation MP3 encoders like Xing against a moden encoder like LAME can tell you that LAME offers a huge improvement in quality over Xing using the same or even lower bitrates.

The SoundStorm encoder is meant to be fast (real-time is required), low CPU load, and offer acceptable quality, while a commercial encoder can (for example) make 2 passes through data to optimize the allocation of bits and spend as much CPU power as desired to decide what parts of the audio to throw away.

We are not saying the content is better than the end result of a commercial mix that has gone through lots of careful post processing to ensure optimum quality. Rather we are saying that the user gets better quality than if the DICE had used the standard rate, particularly noteworthy in the maintenance of channel separation right through the full frequency range of the DICE encoded content.

Nice links BTW.

 

[dderidex]

Indeed, I'm still trying to determine what that article means to my situation.

Creative Audigy 2 analog out to Klipsch Promedia 5.1 Ultra
-or-
Soundstorm digital out to a Creative decoder to Klipsch Promedia 5.1 Ultra

It's a tough decision, and the comparison vs DVD audio was my big concern. If the Soundstorm was even 'really close', then I'd probably go with that solution...but I didn't realize DVD didn't CUT OFF higher frequencies (just a DICE thing) or that there would otherwise be a noticeable difference in quality due to additional passes, even at lower frequency.

Tough decision.

Audigy 2 -> Klipsch 5.1
- Lose front panel audio ports
- Higher CPU usage than SoundStorm
- 44khz to 48khz resampling on all audio sources
- Takes up PCI slot (only have the 1, so...)
- Famous Creative bloatware drivers
+ Ultimately, will have to use Audigy 2 someday, anyway, for A64 in the future
+ EAX 3 and EAX 4 support for games that have it
+ Let's face it, all game devs code using Audigy = better game support

Soundstorm -> Receiver -> Klipsch 5.1
- Lossy DICE encoding effects audio quality
- Once upgraded to A64/Audigy combo (no sooner than 2006), receiver becomes useless
+ External receiver has remote control
+ PC already has all Soundstorm hardware (ports, etc) in place - seem wasted not to use

 

[dderidex]

Interestingly, to add more confusion, Tom's Hardware (hardly the most reliable source) claims that the DDTS-100 handles Dolby Digital decoding to analog BETTER than the Extigy does. And the Extigy ~ Audigy 2, right?

Compared to a computer software decoder in which Creative's external Extigy sound card is connected to these same Gigaworks speakers, the sound is clearer when fed through the DTTS-100 and is much more like the control system, the home theater system.

 

[Auric]

The best quality, features and performance is going to be had with an Audigy 2 output via analog to a good amplifier. Resampling worries is a complete red herring and should only even be considered when using a very high quality DAC, amplifier and speakers, otherwise any one of those can degrade quality much more. CPU usage difference is insignificant. SS is lacking in quality and features and would additionally rely upon an external DAC, which in the case of PC kits is not going to be great. Also, at some point you will replace the mobo so I don't see any compelling reason whatsover to want to use the SS.

 

[DaveSimmons]

Can your mobo send 6-channel analog out to the Klipsch?

Analog is lossless, uncompressed -- the main advantage of using a digital signal is the single cable and less chance of interference from the PCs own electromagnetic emissions.

That, and most receivers don't offer bass management (redirection) for their analog input, so bass management must be done by the PC's software instead.

 

[shinotenshi]

SoundStorm does not chop. OMG i wish this stupid rumor would die already. There was a software issue with certian Mp3 players. The encoding is fine, its the player that screws. as a side note this never effects games or CD's.

 

[dderidex]

Originally posted by: Auric
The best quality, features and performance is going to be had with an Audigy 2 output via analog to a good amplifier. Resampling worries is a complete red herring and should only even be considered when using a very high quality DAC, amplifier and speakers, otherwise any one of those can degrade quality much more. CPU usage difference is insignificant. SS is lacking in quality and features and would additionally rely upon an external DAC, which in the case of PC kits is not going to be great. Also, at some point you will replace the mobo so I don't see any compelling reason whatsover to want to use the SS.

Compelling reasons would be:
+ No Creative 'bloatware' drivers
+ Lower CPU usage
+ No audio resampling (Creative resamples all sources, including 44.1khz CD audio, to 48khz)
+ Superior DAC to the Audigy 2 (remember that the SoundStorm solution involves me buying a quality external decoder)
+ Continue to be able to use my front-panel audio ports
+ Keeps my one PCI slot free

Of course, you did hit on one of a few compelling reasons to go Audigy 2, of which there are a few:
+ Support for EAX 3/4 (realistically, though, all games have decent fallback to EAX 2 so far)
+ I will eventually upgrade to an Athlon64 = no SoundStorm, and will need another soundcard then, ANYWAY with no use for an external decoder

Originally posted by: DaveSimmons
Can your mobo send 6-channel analog out to the Klipsch?

Analog is lossless, uncompressed -- the main advantage of using a digital signal is the single cable and less chance of interference from the PCs own electromagnetic emissions.

That, and most receivers don't offer bass management (redirection) for their analog input, so bass management must be done by the PC's software instead.

Well, it *can*, of course. But it's using the motherboard's onboard AC'97 CODEC as the DAC, and I've never heard a reviewer ANYWHERE that didn't think that sounded like crap.

The advantage of using digital on the SoundStorm is that it bypassed the crappy onboard DAC and replaces it with a competent external DAC.

Using the Audigy wouldn't need an external DAC, as it has a competent one built in.

I confess, I have thought about just using the onboard analog 'for a while' until I can afford an external decoder....but I've sort of bet my wife I can go all the way through 2005 without any PC upgrades, so that's a LONG 'while', and I'm not sure I could live that long with Klipsch 5.1 Ultras on an AC'97 DAC.

 

[tiap]

Sounds like your into your sound more than most people. I recommend you at some point you go with m-audio revolution using digital out to a home theatre decoder/amp. That way you cover all your possibilities as far as connections in/out and and get the best possible sound no matter what. Keep in mind, this way you don't need a powered speaker system. Also try to stay away from any Creative with all the bloatware. All they have is eax support if that's important for you.

 

[DaveSimmons]

Unfortunately, if you care about sound quality and game compatibility it's hard to avoid being assimilated by the Creative.

Other cards like the m-audio offer excellent sound for music and movies, but (last time I checked) were not great cards for gamers.

The simplest solution for dderidex is to admit that resistance is futile and buy an Audigy 2 or 4, which can be moved to an A64 system later.

 

[dderidex]

Ehhh...while it was pretty much impossible to avoid supporting Creative in some way with this upgrade, I've decided to put off inflicting their drivers on myself for the time being.

I found an Extigy on eBay for cheap, and since those have the ability to work as a standalone Dolby Digital Decoder, that should work fine for what I need. I get to keep using SoundStorm, and can enjoy the Klipsch 5.1 Ultras.

Next year some time, well, 2006, actually, when I build a whole new system, we'll see what's out there.