X-Fi and the Elite Pro: SoundBlaster's Return to Greatness
by Derek Wilson on August 30, 2005 11:59 AM EST- Posted in
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New Features, Possibilities, and Modes
The main new audio processing features of the X-Fi line are the 24-bit Crystallizer and CMSS-3D. These features, as well as the onboard RAM and the three modes of operation (gaming, entertainment, and creation) will be explored in this section. We know what each of these features is and the basic principles on which they operate. While we could make a much more thorough analysis of the quality of these features, if we had some actual math to go on, it is understandable that Creative would want to protect their investment by keeping the intimate details of the architecture private. What we do know should be enough to go on for now.The 24-bit Crystallizer
The 24-bit Crystallizer takes 16-bit audio and tries to add dynamic range to the audio signal. If we were to convert our 16-bit audio stream to 24-bits, we could essentially do so by adding 8 zeros to the least significant end of each sample. It becomes clear that the highest value that a sample can take on is much less than the highest value possible with 24-bit audio. Likewise, on the low end, the audio stream isn't capable of representing values between zero and 256. The basis of the 24-bit Crystallizer is to fill in these least significant bits with meaningful data and thus, expand the dynamic range of the audio. What, exactly, is meaningful data in the least significant bits? We're glad that you asked.Audio engineers are big fans of compression. Applying compression to a sound decreases the dynamic range of a sound in order to preserve the loudest and quietest parts without clipping or burying the subtleties in noise. This is very necessary to make good use of 16-bit audio, as things like whispering over a snare hit are not easily representable otherwise. Knowing the basic manner in which audio engineers go about applying effects to sounds, Creative can try to reverse-engineer the process to add more data where it seems necessary.
Details on the technique are fuzzy at best, but we do have some information. The algorithm doesn't simply expand the audio signal; it looks for recognizable patterns in frequency and time and applies algorithms that fill in the data where necessary. For instance, the X-Fi hardware is able to detect something like a kick drum hit and use the sound and proportionally weighted, transient, low-frequency data to boost the impact of the event.
The algorithms focus on the energy flux in different frequency bands in order to localize the impact of the effect. This means that things like snare and symbol hits, the plucking of strings on an acoustic guitar, the slapping of a string on a bass, and gunshots in games should all become more distinct. Each sound will be enhanced according to its energy flux, frequency, and waveform. Creative states that this can even help clean up the high end on MP3 encoded files. What this doesn't enhance quite as well are quiet subtleties in the audio signal.
CMSS-3D
For 5.1 sources played on headphones with CMSS-3D, Creative uses HRTF (Head Related Transfer Functions) to virtualize the position of each audio channel around the listener. This technique is augmented with simulated environmental reflections, which attempt to improve the externalization of sound to the listener. These environmental effects are more subtle than the Dolby Headphone effects and are meant to convey a listening environment that matches the recording rather than one that fits the room in which the listener is sitting.When enabled for 3D virtualization with two speakers, the methods used are similar to that of the headphone implementation. Rather than adding environmental reflections, this CMSS-3D mode includes a cross-talk canceller to make sure that signals from one speaker are not destructively combined with signals from the other at the listening sweet spot. Unfortunately, there is still a sweet spot for listening to audio in this mode, but settings like speaker angle are easily adjustable.
Probably the best use for CMSS-3D has nothing to do with two speaker setups. Getting the most out of a 7.1 channel audio setup is much easier with CMSS-3D. We still don't recommend using CMSS-3D for stereo sources, but for listening to 5.1 audio, CMSS-3D will do a good job of fitting the 5.1 sound to 8 channels. For creating a multi-channel environment with a two-channel source (if we absolutely must), our favorite solution is still Sonic Focus' implementation on Intel hardware. It's a shame that they won't open up their software for other hardware.
64MB onboard RAM
The top two models in the X-Fi series feature 64MB of SDRAM on the sound card itself. This feature is called X-RAM, but that isn't a technical term. X-RAM is a marketing name given to maintain the X- moniker of the card itself. This RAM is supposedly included to enhance the performance of games. Until games are written to take advantage of this feature, we will have to simply accept the possibility for performance improvement.Creative has shown us some numbers that they have run using UT2K4 and a special patch that allows for playing over 100 voices at a time (currently only 30 are supported in the game), as well as uploading uncompressed sound files to the onboard memory. The numbers show a pretty big performance improvement when X-RAM is enabled in this case. Unfortunately, we don't know how real world this test is. Without having the patch to test ourselves, we can't really know what's going on. If we are more than tripling the number of concurrent voices, we would hope to see some sort of quality improvement as well. A performance improvement for a feature that isn't necessary is a useless test.
We really need to spend more time with games that currently support X-Fi to see if we can find a case where the extra RAM affects performance. Our best guess is that we won't see real impact from this feature until developers realize that they can target the Creative solution to deliver a higher quality audio experience. Playing audio with higher sample rates, adding voices, using uncompressed audio to save CPU overhead, and freeing system RAM for other uses should be quite attractive to audio designers.
3 Modes of Operation
The final major feature is the inclusion of three distinct modes of operation. This feature is necessary because of the complexity and flexibility of the Audio Ring architecture. Tradeoffs are necessary for every type of audio application, but a configuration that can switch between modes depending on the task at hand could be a major development in the "one size fits all" audio department. These are the features of the different modes.| Gaming | Entertainment | Creation | |
| Video Game Frame-Rate: | YES | NO | NO |
| Hardware 3D Audio Processing: | YES | NO | OPTIONAL |
| Environmental Effects: | YES | OPTIONAL | OPTIONAL |
| High-Resolution Audio Playback: | NO | YES | YES |
| Audio Enhancement Processing: | NO | YES | OPTIONAL |
| 2-Channel to Multi-Channel Up-Mix: | OPTIONAL | YES | NO |
| Multi-Channel Audio Recording: | NO | NO | YES |
| Hardware MIDI Playback: | NO | OPTIONAL | YES |
| Hardware Effects: | YES | YES | OPTIONAL |
| Sample-Synchronized Record and Playback: | NO | NO | YES |
| Low Audio-Streaming Latency: | NO | NO | YES |
| Bit-Accurate Audio Capable: | NO | OPTIONAL | YES |
Professional recording requires low latency, especially when using ASIO drivers. Therefore, it makes sense that Creative would implement a mode targeted at getting audio in and out of the Audio Ring as fast as possible. Effects possible in Creation mode are limited to those that can be performed very quickly, and audio comes through the chain as unmessed as possible. Less than 2ms latencies are possible in this mode. Again, our only complaint with the Elite Pro as a professional solution is its lack of balanced I/O.
Entertainment mode focuses on the music and movie experience. Options for enhancing both stereo and surround sources are pushed to the foreground and features like the 24-bit Crystallizer and CMSS-3D will likely be heavily used in this mode.
Gaming mode is optimized for creating a multitude of hardware accelerated voices and processing them to create the best real-time 3D that audio developers can throw at it. With up to 127 3D + EAX voices, extremely complex effects are possible. Under this mode, X-RAM can be used to assist in the storage and playback of audio files.
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mindless1 - Wednesday, September 21, 2005 - link
Unless you can provide the technical means used, I will tend to disbelieve this as the card itself is evidence to the contrary. You can't do in software what the hardware doesn't "really" support and have same result. To get 44.1 out without resampling, you have to START with a 44.1 clock rate, have that specific frequency generator. You can't do "math tricks" to derive a 44.1 rate, it's just an end-run to same end- resampled.Resampling IS clearly a negative. "clean signal" is foolish talk in the context of audio, because typical distortion figures are not enough to discriminate what the human ear can. Proof-positive is that people can, reproducibly, conduct blind abx tests and discriminate between two different sources that have insignificant "measurable" signal differences.
Resampling is always considering one of the most significant factors, it destroys the music's detail to do it. If the rest of your gear is crap and you can't hear the difference, it matters less- but if you are buying this card I would HOPE it's not to be paired with low-end links in the rest of the system.
When you "set a clock", you are causing it to resample. Doing without resampling requires multiple clock crystals, at least the base frequencies if upsampled further for better DAC resolution on an analog output. You don't "set" a clock rate in such a superior scheme, only selecting (which) clock input.
Byzantine - Wednesday, September 28, 2005 - link
In Audio Creation mode you can set "Bit-Matched Playback" which will disable the SRC and any EQ. The X-Fi has a flexible signal routing architecture so that you change the sampling rate. The Digit-Life review confirms that you can play back at 44.1kHz without SRC.I guess you haven't auditioned the X-Fi yet, otherwise you would not notice how improved the SRC is on the X-Fi compared to the previous generation. Even if you did not like the SRC, there is now the option to avoid the SRC altogether. Music listening is very subjective, so there's no way people will agree on the quality of the sound. If the X-Fi is not up to your standards, then don't get it. I'm personally more than satisfied with my Elite Pro.
Sea Shadow - Wednesday, August 31, 2005 - link
How do you know this, I have yet to see any data proving or disproving your rantings.yacoub - Wednesday, August 31, 2005 - link
I'll consider it a return when they offer it for $100-200. This is nothing more than Creative moving to a price model similar to other computer hardware components such as videocards. The only thing returning is the bullsh*t.Araemo - Wednesday, August 31, 2005 - link
Hello? Anyone out there? Creative, 2004 is calling, and it would like a PCI-express audio card.More seriously, I'd be hesitant to spend $100+ on a new sound card for my new system(about 5 months away) that may not work on my next system after that(About 2 years away). Sound cards are not a huge performance bottleneck w/ only two speakers. I don't NEED a new card, so I'll probably just use the Realtek 850 audio on my next motherboard.
Why would Creative release their only innovative product from the past 5 years, without support for the most current interface? I'm sure they can add it down the line, but it doesn't make sense to me not to have it now.
xeizo - Wednesday, August 31, 2005 - link
There is no PCI-E soundcard out there yet, strange it may seem, but that must be because the industry had an easier time introducing PCI-E on motherboards than they expected, and so no need to push it further by rushing "killer hardware". Or mabe more right, the killer hardware was SLI.There are other much more interesting audiowork being done than X-Fi, like the team which are writing an audiodriver for Geforce-cards. There we can talk about a capable DSP, and with lots of "X-RAM" already in place.
As been pointed out, the most annoying thing about X-Fi are the driver issues:
no Linux-driver, or even support for external development of one
no Windows Vista-support
the general low quality of ALL Creative drivers, the slow updates or correction of bugs, the bloat, and not being able to download full drivers but must buy a CD.
And what about usability ? If I build a new computer, do I really need more audio-performance than what I have ? Yes, if I'm a musician I need "as much" audio performance as I can get, but I don't usually get it from a soundcard(or audiointerface) but instead I get it from software or dedicated hardware. What I need is a fast, faster, fastest cpu and lots of matching RAM. No need to even bother to use any part of Creatives software bundle, as there already are endless amounts of much better dedicated music-creating software out there. All i need is a fast PC and a clean sounding audio-interface. Even an Audiophile 2496 for under a 100$ sounds clean enough for professional use and has as low latency as the 400$ X-Fi, and the drivers aren't buggy. It just works, clean and simple. If I wan't to make music I would be much more interested in Creatives E-MU cards, especially since X-Fi are so insanely highly priced. The cheaper cards in the X-Fi line will NOT do to take make music on because they use inferior AD-converters, which renders the good enough DACs on them useless for recording live instruments.
For other use, ie games, gamers aren't audiophiles. They just want cool effects in their game, any Audigy-card will do for that. Analogue sound, that is, if you use SPDIF to good quality external hardware i guess there aren't many that can't do with an ALC850.
And pure audiophiles who don't make any music, just listens to it ? Well, if the musician who made the music thinks an M-Audio-card is good enough to create the music on I see no reason why an Audiophile can't think that the same soundquality as in the studio is good enough for him.
And movies ? SPDIF and ALC850 once again ... but i prefer my standalone DVD-player.
In fact, noone NEEDS X-Fi, it's just bloatware and marketing. Most people annoyed with their soundquality need better speakers, not better soundcards. Or prove me wrong.
Araemo - Wednesday, August 31, 2005 - link
Some agreements and counter-points:In my current system, I have an audigy(First gen) "mp3". And the nForce 2 soundstorm w/ dolby digital(I think? NF7-S v.2.0, I don't use dolby if I do have it thoguh). I have no room for a 4.1, 5.1, 6.1, etc.. sound system, and it would just annoy my roommates and neighbors. So I wanted to find a good, high quality 2.1 system w/ optical audio in.. I couldn't find one from any computer speaker company. In retrospect, I should have looked at home theatre type stuff? But that probably woulda been at least twice the price(Good speakers + good amp?, vs. my logitech 2200s for about $70). My audigy, due to drivers, or whatever.. crackles after the system has been on a while, and multiple sounds are playing(Winamp + any game?). The Soundstorm has SHITTY sounding midi playback. I have both cards installed and configured.. midis play through the audigy's hardware midi playback, are 'recorded' on the audigy without leaving the card, and played back through speakers hooked up to the soundstorm. If I get an ALC850 sound card, I'll probably have to do the same thing to get decent midi playback. Plus, as scary as it sounds.. Creative's drivers are the BEST among all the consumer 'gaming' sound cards. And they SUCK ASS. I know from experience that the intel chipset built-in audio isn't always as stable as my audigy was.. (At least on my first gen centrino chipset). So, no, not everyone can put up with just an ALC850.. 99% of people can, but anyone who has a collection of MIDIs and likes decent sound banks.. has to buy creative, or get dedicated MIDI hardware.
Doesn't PCI-E have a transport mode designed to give predictable latencies? I would think the ability to have multiple sound cards interacting with the controller 100% independantly, getting all 1Gbps(Per lane) of bandwidth, would be desirable for high quality multi-channel sounds. It IS refreshing to finally see another creative product that isn't based on the Emu10kX chips. And who knows, if ATI can make their drivers good enough that some people are saying they're better than nVidia(In certain areas), maybe even Creative can pull their drivers out of the gutter too.
DerekWilson - Wednesday, August 31, 2005 - link
That needs to be said quite a few more times ...
mindless1 - Thursday, September 1, 2005 - link
True, the speakers are usually the weakest link but that doesn't begin to make the sound card any stronger. Unfortunately as any audiophile will tell you, the better the /rest/ of your gear is, the more you'll notice the weakest link. Can't tell for sure from the pics but it doen't even look like Creative is using decent output coupling caps, which is sad on a $400 card.ceefka - Thursday, September 1, 2005 - link
Plus: would an audiophile be listening to his best CDs from a PC or a standalone high end CD player? I guess I could do without the background noise of a PC and I do not consider myself an audiophile.