X-Fi and the Elite Pro: SoundBlaster's Return to Greatness
by Derek Wilson on August 30, 2005 11:59 AM EST- Posted in
- Smartphones
- Mobile
X-Fi Processing Elements: Exploring the SRC
Sample rate conversion is one of the causes of poor audio reproduction in current sound cards. So, why make such a big deal out of sample rate conversion on the X-Fi? This time, Creative has implemented an SRC that generates very low noise and distortion, and the Audio Ring allows data that doesn't require sample rate conversion to bypass the step altogether. For the conversion of a 997Hz signal from 44.1kHz to 48kHz, the SRC demonstrated -136dB THD+N and +/- 0.00025dB pass-band ripple. Creative says that this is 300 times the quality of the SRC step in previous generation SoundBlaster products. These excellent results allow data to be passed multiple times through the SRC without any significant distortion of the data, making the SRC a key part in effects processing.Pitch shifting can now easily be done on the SRC. Multitasking the sample rate conversion hardware for effects further allows creative to justify the efforts that they put into its development. One thing that Creative says can be dynamically applied to sound in realtime through the SRC is the Doppler effect. This could allow game designers, for instance, to apply a Doppler effect to all moving sound in a scene relatively easily. Sound synthesis can also use the SRC to change the pitch of a sound easily. The SRC also fits into 3D audio processing.
In pro audio applications, the SRC can be used to avoid the necessity of an external clock for syncing audio signals. Synchronized audio is still possible on X-Fi, but audio from multiple sources can be mixed with very good results using the SRC. As we have said before though, applications that do not require sample rate conversion will be able to bypass the SRC all together.
In order to create such a high quality SRC, Creative created a three-step hybrid filter. First, the sample rate is linearly increased by a factor of 2 using fairly simple math - no complex filters are needed for this step. The next stop along the way to sample rate conversion is a poly-phase FIR filter that up-samples its input to 2*(desired_sample_rate / original_sample_rate). This gives us data with a sample rate that is 4 times the desired sample rate. The final step is to reduce the sample rate by a factor of four (which is also an easy computation). Aside from increasing the quality of the sample rate conversion, increasing the sample rate to 4x the desired final rate also serves as an effective anti-imaging filter. The highest frequency that can be represented in sampled digital audio is half the sample rate (as per Nyquist). Imaging is a "ghost" of the audio signal in the range between the sample rate and half the sample rate. Assisting with anti-imaging is a by-product of the X-Fi SRC.
Facebook
Twitter
RSS
110 Comments
View All Comments
JNo - Thursday, September 1, 2005 - link
In fact, if Anandtech could do a review of the HDA X-Mystique 7.1 it'd be appreciated as I've heard quite a few good things about this card, not least its reasonable price point and dolby digital live output.By the way, on a separate note, for all the people here giving anandtech grief, people should look at more than just one site before making informed purchasing decisions and anandtech did much better than tomshardware which was extremely partisan. Also, I would like to use and trust dedicated sound sites like www.3Dsoundsurge.com but unfortunately they are often too slow in reviewing new hardware...
DerekWilson - Tuesday, August 30, 2005 - link
you can output sound digitally ... dolby sources (DVDs) can be output to a reciever, and audio can be output via SPDIF to a reciver as well ...What you can't do is take a source that's not already dolby (like music, games and the like), encode it to dolby, and then send it to a reciver.
Lwood - Tuesday, August 30, 2005 - link
I found this on the ALSA mailing list (http://www.gossamer-threads.com/lists/linux/kernel...">http://www.gossamer-threads.com/lists/linux/kernel...:"We are not going to get any support from Creative for the X-Fi chip.
We do not get support from Creative for any Creative chip that has a DSP
in it."
It looks like we won't see a Linux driver for the X-Fi anytime soon... :-(
sprockkets - Tuesday, August 30, 2005 - link
Oh well, even nVidia's soundstorm worked in linux, and with the 5.1 encoding out.Reflex - Tuesday, August 30, 2005 - link
I've had these cards in my lab and all I can say is that this is the first time I've ever really doubted Anandtech's credibility. This reads like a spiced up piece of PR from Creative, and subjective listening would not put this as the best consumer audio solution as so prominently stated on the first page of the review.Derek - What the hell is going on here? You don't even include any results from competing products to make such a statement. The war was over before a shot was fired is the impression this review gives. The fact that Creative finally has a card to match the specs that otehr cards have had for three years now makes it a 'revolution'? Sorry, I have been working with these cards for months now and they definatly are nothing special. Just expensive.
flexy - Tuesday, August 30, 2005 - link
100% agree...tried to keep my complaints back, tho.Btw. nice nick :)
DerekWilson - Tuesday, August 30, 2005 - link
Hello,We will be looking at more cards, and including an envy24 based solution is something that we intend to do in the future.
We do include a result from a competing solution -- the Gina 3G is a pro audio card which has excellent audio quality. The Elite Pro is closer to a pro audio product in the component selection and construction.
envy24 based consumer products don't score as well as the Gina 3G from what we have seen. Granted we do have to test this for ourselves, but we would certainly expect the Gina 3G to outperform something from Terratec or M-Audio.
That being said, the X-Fi outperforms the Gina 3G in just about ever test we ran.
It is very difficult to subjectively compare audio between cards. There have been some cases (the audigy line) where there was a very clear problem with the aural experience. With the X-Fi line, we can no longer say that we can hear problems with the audio.
We spent days listening to this card, the Gina, and the Audigy 4. We frankly disagree with the statement that subjective listening does not put this card on par with the best audio solutions out there. We found no reason in our subjective listening tests to conclude otherwise.
On top of that, after simply listening to the card for days, we ran the RMAA tests. These tests showed clearly that not only was the card void of any issues, but that the quality of the output was much closer to the source than any other card we tested. These two points add up to the conclusion you disagree with.
And as we said, if this card performs better than the Gina 3G and the Gina performs better than consumer level envy24 parts, it stands to reason that the X-Fi would outperform just about everything but a LynxTWO ... and even then we would need to run some tests of our own ...
The big problem is that at these incredibly low noise levels, high dynamic range, low distortion, good separation, etc... it is very difficult to hear differences in the audio. To the average person, the audigy 4 Pro, Gina 3G, and X-Fi will sound exactly the same. To a hardcore audiophile, we wouldn't doubt it if the X-Fi won their hearts. The X-Fi (in spite of its features) can provide a very true-to-the-source signal with less coloration than all but the best pro audio cards out there.
For musicians, the high quality provides a better platform for work than the rest of the pack -- unless, of course, balance audio is desired.
Show me a consumer audio card that matches the specs of the X-Fi ... From the tests other people have performed on the LynxTwo B at 16-bit/44.1kHz (the unofficial standard in PC audio quality), the X-Fi posts http://audio.rightmark.org/test/lynx-two-b-1644.ht...">better numbers in every category but frequency response (and it's darn close in that area)...
The high end components used do not make the X-Fi Elite Pro "nothing special" ... They make it nothing most people will need. And certainly, between this and other products that use good quality components, most people won't notice much (if any) difference.
We very much agree that the card is too expensive. And please rest assured that we will be comparing this card to an evny24 based solution -- and hopefully a lynxtwo -- in the future.
Thanks for the feedback,
Derek Wilson
yacoub - Wednesday, August 31, 2005 - link
Look into the BlueGears X-Mystique. It's pretty much the best PC soundcard available at a reasonable price right now - and it's not Creative so there's no assorted bloatware to install.Reflex - Tuesday, August 30, 2005 - link
Derek -I am not trying to bash you here, however you have to understand that when you start an article by proclaiming something the best in its class, but then your test does not include the other solutions in the class at all, that things seem fishy.
I work with audio devices for a living. I've worked with the X-Fi since it was a prototype(as have a couple dozen other people in my lab). Certainly it is an improvement over previous Creative efforts, and at first we were a bit wowed by the paper specs and proposal. However after working closely with it for months, I honestly can say that no one here feels its anything special. Perhaps some of that is the novelty wearing off, but in any ad-hoc test with someone who hadn't heard it before, they could rarely tell the difference between it and an Audigy, and the M-Audio Revolution generally was said to produce clearer sound. Not that our tests were scientific or anything, we weren't trying to write articles for publication.
I'd really suggest some blind tests with a variety of content. I think you may be suprised to find that while for MP3's the X-Fi sounds good, for CD's and especially SACD's the mid-range is poorly reproduced. Make certain you use a wide range of music, and prefferably classical numbers that you know very well.
Something else is you could list what type of speakers/headphones and recievers you are using, if you are testing with something like Klipsch then your credibility would go down considerably for anything but games and action movies, after all the card cannot make up for poor speakers(when measured by reproduction accuracy, not volume).
I would suggest establishing a baseline and going from there. Based on my experience, in the 'consumer' segment the M-Audio Revolution 7.1 is a good baseline, however any baseline that you could compare against would be beneficial to strengthening the credibility of the review. Granted anything audio is subjective, but when you say something is 'better' you need to at least be able to point to some specific reasons as to why.
And finally, the section that read like Creative marketing PR was your explanation of their audio architecture. There is nothing inherantly 'better' about the approach Creative is taking, it is simply different, there are both advantages and drawbacks. Furthermore, while they make the product seem like the 'next generation of audio' no one has managed to get a commitment from them to support the upcoming Windows Audio Architecture that will be a part of Vista, without that support they will be behind several others. Their lack of support for Linux is also a drawback for many.
Thank you for the effort, I hope that this feedback will help you improve your audio reviews in the future. I have read AT since the beginning and rarely doubted what is posted here, there just seemed to be some rather glaring flaws in how this review was handled. At least in my humble opinion.
DerekWilson - Wednesday, August 31, 2005 - link
Thank you very much for the helpful feedback. Some of your suggestions will absolutly make it into future audio reviews.I would tend to disagree with your assesment of Creative's architectural direction. If the intent is to very heavily process many audio streams, then the flexibility and power are helpful. This could be a boon to game designers or electronic musicisans looking for some hefty sample rate or dsp power.
For straight up listening to a single source or recording the architecture is unnecessary.
I agree that windows driver and linux support are drawbacks as well.
We absolutely appreciate and need our readers feedback. Thanks for taking the time.
Derek Wilson