DO YOU TWEAK YOUR CD'S?

[fjf]

The one thing I never understood is how different data CDs are from music CDs. We can extract data from CDs without problems (the standard was designed to include redundant data to avoid corrupted info) and therefore we can copy any software from CD to CD indefinitely and it will still work, meaning that the information in it has not been degraded. However, when what it is being read is music, the the terrible jitter appears and (instead of a cheap computer CD reader costing $30) we need a $5000 CD reader unit to fight it. I do not get it.

 

[JaZZ]

Quote:

Originally Posted by fjf /img/forum/go_quote.gif The one thing I never understood is how different data CDs are from music CDs. We can extract data from CDs without problems (the standard was designed to include redundant data to avoid corrupted info) and therefore we can copy any software from CD to CD indefinitely and it will still work, meaning that the information in it has not been degraded. However, when what it is being read is music, the the terrible jitter appears and (instead of a cheap computer CD reader costing $30) we need a $5000 CD reader unit to fight it. I do not get it.

Data don't need correct timing to still be intact, in contrast to music, where inaccurate timing changes the signal form.
.

 

[MatsudaMan]

Yes. Before I put them in, I wipe them on my jeans.

 

[Mikael]

Quote:

Originally Posted by Todd R /img/forum/go_quote.gif **silent except for the crikets chirping** The record still stands, no takers

Well, I'm not going to send a CD across the world for this discussion.

I should also add that the reason that I haven't really continued this discussion is that I'm trying to cut down on my forum addiction (not just this board). Technical discussions have been taking up way too much of my time and they usually lead nowhere.

With that said, I just had to write the answer below... Damnit!

Quote:

Originally Posted by JaZZ /img/forum/go_quote.gif Data don't need correct timing to still be intact, in contrast to music, where inaccurate timing changes the signal form. .

Don't D/A converters sample the incoming data stream? In other words, the incoming signal is sampled at discrete intervals at the current sample rate. This would mean that a digital in signal would be read only at the middle of each pulse (ideally). This means that it is immune to slight displacements of the pulses, as long as the they don't add up to displacing the signal into the next sample point.

I'm trying to illustrate my point again, with another picture. I threw it together real fast, which you can probably see... Anyway, it shows the sampling of two digital signals. Sampling is done at each dashed line. As you can see, despite the different timing of the signals, a D/A would get the same insignal ("1010101").

 

[JaZZ]

Quote:

Originally Posted by Mikael /img/forum/go_quote.gif Don't D/A converters sample the incoming data stream? In other words, the incoming signal is sampled at discrete intervals at the current sample rate. This would mean that a digital in signal would be read only at the middle of each pulse (ideally). This means that it is immune to slight displacements of the pulses, as long as the they don't add up to displacing the signal into the next sample point.

As I see it, to reproduce the real-world situation (without buffering and reclocking, well understood) the dashed lines have to be shifted towards the middle of the pulses. Moreover, the pits on the CD aren't rectangular, but in fact have rounded starts and stops. So the signal shape would rather look like sine waves in reality.

In any event: Jitter is exactly that: inaccurate timing. It's not about 0s becoming 1s and vice versa.
.

 

[SoundEdit]

Quote:

Originally Posted by JaZZ /img/forum/go_quote.gif Data don't need correct timing to still be intact, in contrast to music, where inaccurate timing changes the signal form. .

Well, this topic is interesting. Your CD player is all about the data. If the signal were not buffered then you would have stronger case, however the timing of the conversion from data on the CD is insulated from the actual reading of the data stream from the disc and the timing of the playback is based on the data and not the read speed of the data off of the CD except in the case of grossly unreadable data. If it is not then your CD Player is improperly designed.

Clearly arguments about differences at the threshold of detection are going to be contentious. It seems like one should be able to answer the question of most near threshold audio claims twofold:

First off, one needs to establish that the observed differences are real and repeatable.

{ABX mention removed}

Once you have established that the phenomena is real then you can go on to theorize why the tweak works.

I would think given the cost of high quality audio gear that people would have a great interest in separating what works from what merely seems to work so they can allocate their budget on items that will really make a difference--especially given how ripe for known frauds the high end audio market is ($400 wooden volume knobs, cd "de-magnitizers," $500 AC power cords...)

If people want to spend their money on questionable goods, I wish them well. But if they are going to advocate them I would hope that they would welcome the kind of review that is systematic and allows people to show that it really is possible to hear the difference.

Please don't mistake my thoroughness for dogmatism. If these tweaks work I'd like to know about them. However, it only makes sense to want to know for certain which work if any. And proof of any positive claim is the responsibility of the claimant. Subjective impressions are evidence, but they are not convincing evidence until they are part of a methodical test that accounts for human factors.

Edit:

My apologies for mentioning ABX. I did not realize what the initialization "DBT" referred to in the Forum Title.

 

[edstrelow]

Quote:

Originally Posted by SoundEdit /img/forum/go_quote.gif I would think given the cost of high quality audio gear that people would have a great interest in separating what works from what merely seems to work so they can allocate their budget on items that will really make a difference--especially given how ripe for known frauds the high end audio market is ($400 wooden volume knobs, cd "de-magnitizers," $500 AC power cords...) If people want to spend their money on questionable goods, I wish them well. But if they are going to advocate them I would hope that they would welcome the kind of review that is systematic and allows people to show that it really is possible to hear the difference.

My point about many disc tweaks is that they are not expensive. E.g. Try sanding the inner and outer edges of discs and paint them black (or green).
How much are you out, 50 cents for a marker? Try it and listen.

 

[Vul Kuolun]

Quote:

Originally Posted by Todd R /img/forum/go_quote.gif **silent except for the crikets chirping** The record still stands, no takers

How about swapping?
You send me one of your discs, and i'll send you a set of healing stones. Or a pyramid made of filament to put on ones head, preventing the wearer from harmful cosmic radiation? Or wait a minute... how about this "Watchtower"-Booklet, signed by the author (a certain Jehovah guy or something) himself?

What do you think?

 

[Todd R]

Quote:

Originally Posted by Vul Kuolun /img/forum/go_quote.gif How about swapping? You send me one of your discs, and i'll send you a set of healing stones. Or a pyramid made of filament to put on ones head, preventing the wearer from harmful cosmic radiation? Or wait a minute... how about this "Watchtower"-Booklet, signed by the author (a certain Jehovah guy or something) himself? What do you think?

How about you go play in the highway?

 

[Vul Kuolun]

Quote:

Originally Posted by Todd R /img/forum/go_quote.gif How about you go play in the highway?

Ah, i see. No real interest, just prejudices about things you havent tried.

 

[Todd R]

Quote:

Originally Posted by Vul Kuolun /img/forum/go_quote.gif Ah, i see. No real interest, just prejudices about things you havent tried.

No, that would be you.

See everybody!
They would rather sit back & mock rather than give something an honest try. Might be afraid to find out they were wrong about something.
Happens everytime.

BTW, you need to step back from insulting a religion that someone here might follow. Comments like that might get you banned.

 

[fjf]

Quote:

Originally Posted by JaZZ /img/forum/go_quote.gif Data don't need correct timing to still be intact, in contrast to music, where inaccurate timing changes the signal form. .

I still don't get it. I must be a bit silly

. Bytes are bytes, and if you can read them correctly with the proper correction algorithms and buffer them and you have a quartz clock precise to the billionth-part-of-a-second, then...Maybe the engineers are not that smart

 

[Todd R]

Quote:

Originally Posted by fjf /img/forum/go_quote.gif I still don't get it. I must be a bit silly . Bytes are bytes, and if you can read them correctly with the proper correction algorithms and buffer them and you have a quartz clock precise to the billionth-part-of-a-second, then...Maybe the engineers are not that smart

Maybe this article will help you.

 

[DarkAngel]

I have almost 3500 Cds and for last couple years I just use Shineola CD cleaner once when CD arrives, especially used Cds which are often pretty dirty.

I have the newest small diameter Herbies Grungebuster matt but usually don't use it, does seem to slightly improve poor sounding Cds by removing some "grunge"

I was using the old blue gel Auric Illuminater few years ago, but stopped when new clear formula came out........I find it very hard now to completely remove haze from CD, I also only used black marker on outside CD edge.

I have Bedini quadri beam demag unit, but stopped using it couple years ago, just got tired of the process.

I keep a photographers rubber bulb dust dust blower by CDP to blow any dust off CD surface before inserting into CDP.

 

[SoundEdit]

Quote:

Originally Posted by edstrelow /img/forum/go_quote.gif My point about many disc tweaks is that they are not expensive. E.g. Try sanding the inner and outer edges of discs and paint them black (or green). How much are you out, 50 cents for a marker? Try it and listen.

It is fun to experiment sometimes. I wouldn't want to take that away from you. But, if you don't structure your experiments you can come to false conclusions which you will then swear by for years to come.

As to the cost, well not all tweaks are cheap (The Furutech RD-2 CD demagnetizer at $500 comes to mind) and just because some ineffective product is <$100 doesn't mean it isn't a waste of money--especially when you add them all up. Plus, there is the waste of my time. I'd like to think my time is worth something. I don't mind using do play and do experiments but I'd rather play with stuff that actually works than stuff that doesn't and I don't have time or money to play with every supposed CD Tweak--nobody does.

Why people would object to trying to separate what is from what seems like it is is dumfounding. People shouldn't market stuff unless it actually works, and I highly doubt the "cd demagnetizer" will "reduce the noise floor".