Do you ABX? What can you ABX? Do you care?

[HiFiRE]

I was just reading a thread over at hydrogen audio about whether or not a burned cd sounds different than a pressed cd. For the most part people are convinced that unless there is old/faulty equipment or poor writable media there isn't an audible difference that can be percieved by man. Most people feel this is the truth because no one has proven otherwise (that they have read about or witnessed).

I've read about many audiophiles saying that they can tell the difference but I've never read about one subjecting himself to an ABX test to prove it. I find this a curious issue because if no one steps up to the plate to prove someone can tell the difference audiophiles loose a lot of credibility where they could otherwise could be taken seriously.

I would like to hear some opinions from the golden eared folks here about whether they would be willing to ABX a burned cd vs. a pressed cd, various DACs, interconnects and so on. If not why? What if a reward was offered? Do you ABX your equipment or do you trust your memory that much?

 

[drarthurwells]

They sound close but not quite equal.

Best to listen often to A only, for a least a few days. Get a good memory base of it. This is needed to have a solid memory basis of comparison.

Then switch to B and listen to inner detail resolution, 3D image separation and focus, etc.

No copy can ever be as good as an original - critical listening will reveal the difference in a top quality system.

However, a lower quality system will mask such differences in reducing quality to the the lowest common denominator (the copy).

 

[egraaf]

What would cause a burned cd to sound differently? It is binary data, as long as it is copied correctly there is no reason for a difference in sound.

 

[drarthurwells]

Quote:

Originally Posted by egraaf What would cause a burned cd to sound differently? It is binary data, as long as it is copied correctly there is no reason for a difference in sound.

Mainly minute timing errors in processing the data stream.

Try making a copy from an original, then a second copy from that first copy, then a third copy from the second copy, and so on for 25 or more times. Then play that final 25th generation copy and compare with the first generation copy. Tell me if they sound the same.

 

[proglife]

I spent about 4 hours yesterday A/Bing a stock Toshiba 3960 with Vibrapods to a Rotel RCD-991AE. I picked 10 or so albums and made copies of them so I could switch back and forth between the sources and hear the same thing.

I can safely say that there is no difference between the two, to these ears. That said, the difference between the once expensive Rotel and the cheap little Toshiba* is SO subtle that I can't imagine anyone paying any more for the Rotel over the Toshiba, other than for the quicker seek times.


*with Vibrapods...they clean things up on the Toshiba but make no noticable difference on the Rotel

 

[Veniogenesis]

No commercial computer CD burner is capable of zero PI errors and PI failures. You can use Nero CDSpeed (Freeware) (http://www.cdspeed2000.com/) to check the quality of your CDs. Usually you'll get thousands of PI errors even with the best burners available (Benq do exceptionally well). Though the best CD burners are capable of zero PI failures.

For help on using CDSPeed, http://club.cdfreaks.com/showthread.php?t=96285

Go to http://club.cdfreaks.com for more info. They're a forum dedicated to CD/DVD burners. You can learn about error scanning and other cool stuff.

 

[bordins]

Jason Victor Serinus just wrote an article about the Debate in Stereophile March 2006.
The Mystery of Music.
The Great Debate...and Then Some May 2005 (starting article)

He did ABX on power cords and wrote an article about the test.
http://www.hometheaterhifi.com/volum...s-12-2004.html

He got bombarded, at many places - why ABX ?. One below:
http://www.avsforum.com/avs-vb/showthread.php?t=563168

Jason reviewed Marigo Labs Signature 3-D Mat from his ability to perceive discernable sonics.
http://www.hometheaterhifi.com/volum...at-7-2005.html

He got bombarded again - why not ABX ?
http://www.hometheaterhifi.com/forum...ead.php?t=3011

ABX or not ? People always react which way they want emotionally. Music is all about personal preferences.

Blind test MP3 v.s. CD Audio, good to read.
The Magazine for Computer Technique June/2000, p. 92: MP3-Comparison By Carsten Meyer

 

[Garbz]

ABX has it's issues. Often it's possible to switch between things and not hear a difference, however listening to them through from start to end and then playing another in an ABX kinda hightens certain difference more. Personally I think it has to do with the distractions of the non-perfect switching of the stream.

I've abxed a lot of things I own, using ABX software and the help of someone when i don't want to use the computer. But always doing full listens to the songs. e.g. The difference between my dac and my computer's output i can't descern in an ABX test where they are switched back and forth every 10 seconds or so. It's too distracting. Listen to a certain song for about a minute or so and without fail I could tell which is playing it without even hearing the other.

It's strange. That said blind comparisons should be a strict must for all equipment IMHO, however it leaves out the placebo effect. If people believe that they can hear a certain difference in power cords then let them. They spent the money and they think they got a benefit from it. Don't disapoint them by proving them wrong it'll only ruin it for them and thoes who sold them the equipment. If on the other hand you want to be a true objectivist (and as an engineer I try to be as i hope all engineers should) then a blind comparison like abx is the only way to do it when measurment fails.

 

[Chri5peed]

Quote:

Originally Posted by drarthurwells Try making a copy from an original, then a second copy from that first copy, then a third copy from the second copy, and so on for 25 or more times. Then play that final 25th generation copy and compare with the first generation copy. Tell me if they sound the same.

Sorry but thats untrue. We're living in the land of digital now, every file is basically a bunch of 0s and 1s in a certain order.

There is a name computers use, but it ensures nothing is ever lost in copies. So a millionth-gen copy would be the same as the first.

Copies gradually getting worse is what you get using analog, like VHS/Cassette tapes.

 

[ezkcdude]

Quote:

Originally Posted by Chri5peed Sorry but thats untrue. We're living in the land of digital now, every file is basically a bunch of 0s and 1s in a certain order. There is a name computers use, but it ensures nothing is ever lost in copies. So a millionth-gen copy would be the same as the first. Copies gradually getting worse is what you get using analog, like VHS/Cassette tapes.

It's more complicated than that, due to jitter issues. I disagree with the previous poster who said that the copy is always WORSE. In fact, some people believe the copies can be BETTER, because the PC can eliminate some of the original CD's transfer jitter. Here's a very long thread about the issue over at diyaudio:

http://www.diyaudio.com/forums/showt...&threadid=6545

 

[Publius]

I think there are a lot of people replying to this topic with impaired reading comprehension skills.

To reply to the original poster: I've done some solid ABX testing in the past, but it's hard to get me or other head-fiers motivated (just ask halcyon!) People are best ready to contribute to testing when the results are both a) not predetermined and b) important to them. And most people already prejudge what the result of an ABX test like this will be.

In particular, there is no particularly good technical explanation I've seen that explains that bass thing (no actual mechanism has been described for how jitter could do that). The ABX tests I've been most interested in have been things that still have a good possibility of being controversial - lossy encoders and absolute polarity, in my case.

 

[Chri5peed]

Quote:

Originally Posted by ezkcdude It's more complicated than that, due to jitter issues. I disagree with the previous poster who said that the copy is always WORSE. In fact, some people believe the copies can be BETTER, because the PC can eliminate some of the original CD's transfer jitter. Here's a very long thread about the issue over at diyaudio:

Lol, I actually deleted a line covering that.

Its probably more accurate to say the copying process of computers will be completely perfect if there are no external errors.
With XP you'd get an error-box pop-up during a copy and I've never ever had this, so I believe they're always spot-on.

 

[fewtch]

I've tried ABX testing, and I hate it. I find it stressful and unpleasant trying to perceive differences this way, particularly if others are involved and it's some kind of competitive thing to see who can ABX differences the most. Music to me is for relaxation and pleasure, not hard work.

 

[Chri5peed]

Quote:

Originally Posted by fewtch I've tried ABX testing, and I hate it. I find it stressful and unpleasant trying to perceive differences this way, particularly if others are involved and it's some kind of competitive thing to see who can ABX differences the most. Music to me is for relaxation and pleasure, not hard work.

The last bit is true but a restrictive view, ABX testing will have a purpose as long as lossy files exist. Like I said in another thread ABX testing is a space saving device, its to determine which is the smallest bitrate & which lossy codec is most suited to you.
ABX testing various lossless codecs is mindless, they should all sound the same.

People spend ages getting Foobar just right, you wouldn't say thats time wasted. I am quite certain my Foobar as it is provides more listening pleasure to me than a fresh Foobar would.

 

[ilovesocks]

I think what Mr. Wells is saying is that a perfect copy of the data might be sent to the drive every time, but what the burner does with it might not be perfect. A copied disc will probably have errors on it that make it different from the original. If copy a disc and then copy the copy and so on, after a while the errors could mount up, degrading quality.