BLER and Jitter
Maybe you are confusing output jitter from the CD digital output with the potential jitter present in a CD itself or detected from the CD during read? You are correct that CD errors do not translate into digital output jitter.
However, all optical errors can be described as jitter, here's why:
The pits and lands form a series of "T"s of different well-defined lengths. The detected signal is then compared against a clock synthesized from the EFM pulse train. The resulting output EFM pulse train is determined by when the transition in the squaring circuit occurs. If there is a chunk of peanut butter on the disc, it effectively makes a REALLY long "T"(time), and is quantified as jitter of the longest "T", the T11. The T length, whatever the squarer and comparator made it, is put in the EFM buffer as raw data before error correction. As it is analyzed, descrambled and corrected, Ts of incorrect length will translate into errors, so the jitter itself is not propagated, just turned into an error, which may or may not be correctable, that happens later in the circuitry.
Cheers!
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
Maybe you are confusing output jitter from the CD digital output with the potential jitter present in a CD itself or detected from the CD during read? You are correct that CD errors do not translate into digital output jitter.
However, all optical errors can be described as jitter, here's why:
The pits and lands form a series of "T"s of different well-defined lengths. The detected signal is then compared against a clock synthesized from the EFM pulse train. The resulting output EFM pulse train is determined by when the transition in the squaring circuit occurs. If there is a chunk of peanut butter on the disc, it effectively makes a REALLY long "T"(time), and is quantified as jitter of the longest "T", the T11. The T length, whatever the squarer and comparator made it, is put in the EFM buffer as raw data before error correction. As it is analyzed, descrambled and corrected, Ts of incorrect length will translate into errors, so the jitter itself is not propagated, just turned into an error, which may or may not be correctable, that happens later in the circuitry.
Cheers!
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
I took from your comment that I buy one from tier F and one from tier AA, then compare them blind.
I suppose that survey is quite suspect actually.
The single-blind / double-blind evaluation idea was intact at least, even if they didn't fulfill it.
Most reviews rave about metallized capacitors, all I can deduct is to use them plus Cyril Bateman.
This is an other jitter than the one relevant in D/A conversion. The two are not correlated.
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TNT, I don't completely understand your question.
If I direct technicians to build my design, then is it not DIY, or is it DIY? Does one have to solder every lead to make it DIY? How about making custom amps for customers, on a one off basis? I have done a lot of those as well.
If I direct technicians to build my design, then is it not DIY, or is it DIY? Does one have to solder every lead to make it DIY? How about making custom amps for customers, on a one off basis? I have done a lot of those as well.
Again we're locked into the digital domain - conveniently ignoring the fact that there is a mechanical system relying on electricals to do the recovery of the data. I would do some experiments: make multiple copies, bit-identical, of a CD and then create a series of physically unbalanced disks, by adding weight to one side of the edge of the disks, steadily increasing the unbalance; and on another series, shim up the centering hole on one side to cause the play surface to increasingly wobble vertically while spinning. Then we'll see whether we always get "no difference in sound", 🙂 ...
A classic example of this problem occurred at the recent audio show in Sydney: a room which had admirable sound when the digital was sourced from a music player degraded badly when an Oppo unit was used purely as a transport - this is all relative; the Oppo sourced quality was fairly typical of ordinary digital sound: a slightly disturbing, uncomfortable edge in the playback which meant that you rapidly lost interest in wanting to listen ...
To do this seriously, with tight enough controls so that the results had any validity would be a monstrous exercise - most of all, there's no money in it, hence will never be done ... 😉
I was thinking just listen to a cap they claim is horrifying compared to what I normally think acceptable.
Double blind testing would not show significant differences anyway. That it why we don't count on it. Now who can show that all audio designers and reviewers are politically or financially motivated? Especially enough to lie, cheat, or not be honest in their opinions? This is a MYTH. While I have seen and experienced notable exceptions, almost everybody I know in the audio business is just trying to make a good product, in competition with others trying to sell in the same market.
Their relative success in this activity is usually achieved by making an audio product that is as good or even better than the direct competition. Reliance on advertising, rather than audio quality, is usually reserved to companies like Bose. They are the exception that does not show the rule.
Personally, I am tired of being accused of dishonesty, so cut it out!
Their relative success in this activity is usually achieved by making an audio product that is as good or even better than the direct competition. Reliance on advertising, rather than audio quality, is usually reserved to companies like Bose. They are the exception that does not show the rule.
Personally, I am tired of being accused of dishonesty, so cut it out!
I suspect if you shake an external hard drive violently it will still sound the same. If you deformed the disks you could get corrupt files, like half a JPG picture, I've seen that a lot, but a perfect JPG is perfect so I'm not sure where your inquisition of digital media is leading.
Your comments about filling in perceptive gaps earlier was accurate though, we are not passive receptors, we actively and constantly fill our mind with likelihood.
I've been noticing this a lot recently with words and visuals in peripheral vision.
My presence has been requested at a cell phone manu that I can't name and OPPO to consult on audio quality on portable devices, the irony.
E32 redux
And the resulting mistracking will cause a loss of data and E32s, and a potentially degraded sound quality. Uncorrectable errors are not a parameter on a disc, although they could be caused by a disc problem, they are an error flag in the CD Player's error decoder indicating that the error severity exceeded the error correction circuit's ability to correct. It is the incidence of E32s which cause a change in sound, whether due to a mute or interpolation.
Cheers,
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
And the resulting mistracking will cause a loss of data and E32s, and a potentially degraded sound quality. Uncorrectable errors are not a parameter on a disc, although they could be caused by a disc problem, they are an error flag in the CD Player's error decoder indicating that the error severity exceeded the error correction circuit's ability to correct. It is the incidence of E32s which cause a change in sound, whether due to a mute or interpolation.
Cheers,
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
No, the testing would be have to be done carefully to always ensure we never had an E32 - the aim would be to go as close to causing one to happen, without going there; the error correction should be forced to constantly be invoked throughout the playing, but always to be able to recover correct data - the real aim is to put the servo systems under heavy stress, force them to constantly demand current spikes from the power supplies to maintain good tracking.
My belief is that this capability of the mind is what allows convincing sound to be achieved - if a certain threshhold of quality is achieved in playback then the mind can fill in what's necessary, and discard the irrelevant - the listener accepts the illusion as being "real". However, any performance standard below that is not sufficient - the sound is obviously "fake", and the listener loses interest, becomes fatigued, is easily distracted - the goal therefore is to reach that target quality, which most times is quite difficult to do ...
Not E32s
In this case you would be trying to see if a player, when drawing more current from the tracking servo will introduce noise in the analog outputs? Its sad, but many players do this even with good discs, even some moderately priced players. Yet another reason to use outboard D>A conversion.
Cheers,
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
In this case you would be trying to see if a player, when drawing more current from the tracking servo will introduce noise in the analog outputs? Its sad, but many players do this even with good discs, even some moderately priced players. Yet another reason to use outboard D>A conversion.
Cheers,
Howie
Howard Hoyt
CE - WXYC-FM 89.3
UNC Chapel Hill, NC
www.wxyc.org
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