GigaVariRec

vbimport

#1

I started using varirec to record most of my audio cd’s because my CD changer has been erratic lately. I noticed a sharp increase in sound quality, or a decrease in static when burned with varirec +1.

I’ve separately burned audio cd’s with gigarec to stick on a few extra minutes of songs. My CD changer does not like gigareced cd’s though.

So the other day I decided to try burning a 100 minute audio disc with varirec +2. Not only is it working flawlessly, it has remarkably clear sound. It’s nice to have something positive come from my px-716 for a change so i thought i’d share this heartwarming tale with everybody.


#2

Nice. :slight_smile:


#3

Gigarec settings 1 and up shortens the lands and pits so more data can be stored. However this also affects readability as you have noted. Settings below 1 lenghten the lands and pits thus resulting in less space for data but an increase in readability. Yamaha had a similar feature in it’s F1 CD burner model. It was called “Audio Master” and improved the signal quality: http://www.cdfreaks.com/article/88/3

I realize using Varirec has solved your problem but could you try how your changer works with an 0.8x Gigarec disk? Since you have a picky drive at hand it would make a excellent test subject. Thanks.


#4

That’s an excellent idea.


#5

Regarding the sound quality improvement with VariRec, I suggest reading this thread:
http://club.cdfreaks.com/showthread.php?t=134639


#6

I Need to try out other players with vari rec’ed discs. But what I mean by sound quality (and as i state right after it) is that there is far less static or hissing or any other distortion.


#7

OMG… :rolleyes:
I agree with you and JeanLuc. :wink:

Reminds me of an old story where somebody I know stated that he can hear the difference between an original CD audio and a 1:1 copy…


#8

You don’t?

  1. get a good audio equipment
  2. clean your ears
  3. sit down
  4. relax
  5. relax even more
  6. listen to the original
  7. listen to the copy

=> you’ll really hear it!

I know all the arguments about “digital is digital”. The difference arises in the analogue part of the cd-player, upon d/a conversion. Jitter induces disturbing harmonic parts. By nature, a burned copy has less jitter than an original which was produced by a stamp.


#9

loool It happens again. Cool. :smiley:

Sorry man, but you’re wrong.
If one disc contains a pattern of bits, let’s just say 1-0-0-1-0-1-1-0, then the CD player will turn it into the same analog signal every time, regardless if the 1-0-0-1-0-1-1-0 is read from the original or the copy.
Provided that the quality of the disc is good enough so that no read errors occur (at least not ones which can’t be corrected), then the player will always read 1-0-0-1-0-1-1-0, and that will result into the exact same analog signal (apart from added noise, but that is different even if you play the original disc two times in a row). Bad jitter is equal to bad quality, so jitter does not change anything if it doesn’t lead to read errors.


#10

That’s just the theory, “Lord”! Bad jitter means your D/A does not always get the digital stream in the right time, i.e. not exactly in sync with the system clock. This “inaccuraccy” of the temporal pattern leads to phase shifts and/or disharmonic disturbations which influences the subjective perception of the music.
The exact phase relation of the resulting LEFT and RIGHT stereo canal for example is crucial for the ability to locate the position of an instrument in an orchestra. If the signal phase is blurred out due to jitter, the overall impression of the music gets worse. This is by the way the reason why the quality of the quartz in the cd-payer (in addition to the price) dramatically influences the quality of the resulting audio.

However, this effect also strongly depends on the inner architecture of the CD player.

Believe it or not. I also laughed at my friend when he told me that he hears a difference, then I heard it myself with his equipment.

Keep in mind: even in “digital”, there’s always a bit “analog”.

BTW: I read this explanation a couple of years ago in another forum, it is not a product of my own. I do not build CD-Players. But since I know how they work, the explanation sounds reasonable for me.


#11

Kacki is right some CD-Players also have a conector to an external clockgenerator only to keep the clock and sync right. Others like CD transports have the D/A and clockgenerator separated and conected with a special shielded cable (1000s of US$).
Also dont forget that “noise” can have influence on the data before and after the D/A. I read some article where it says that discs which are difficult (dirty land/pits) to read the player needs more power which produces more noise in the player and then corrupting the analog data (I omit that the digital data could get corrupted because we’ll say that the data is read and fed correctly to the D/A). Now the analog data can not be “fixed” with the error correction. The readability of the disc is important as it has influence on noise.
If you look at discs written at different speeds you will see that the edges of the land/pits are different (with the right equipment of course). With high writing speed the edges get “kind of dirty / rougher” compared to a low writing speed, but this does not affect the correctness of the data.


#12

Funny is that I once used the same arguments as Lord does, because this was and is my intuitive thinking. However, I am now convinced that there is a difference and it is mainly - as reported so often elsewhere - in the “airness” of the music, i.e. the capability to differentiate one instrument from the other. The whole 3d impression improves with the “quality” of a copy. But you really need a high end audio equipment to benefit from that.

There are opinions that a laser-burnt cd is more compatible with respect to rising/falling edges of the pit-/land-borders to a cd-player than a pressed cd, and this seems reasonable to mee, too. So concerning the jitter, a burnt cd should achieve better results than an original. I actually verified this with Plextools on several audio cds and their copies.


#13

I still don’t believe it, and I’m searching for sources to prove my opinion. :wink:
But if we agree in one thing, namely that a PC with a decent CDROM drive can rip an exact image of a CD audio (you can copy a CD audio and compare the copy bit-wise with the original, you’ll see that they are identical), then a PC is the perfect CD audio playback device if you activate the “activate digital cd playback for the cd player” (or however it’s called in English) option, because with that option activated, you’re doing a real-time rip (bit-wise identical) and sending the data to the soundcard afterwards (still real-time). There won’t be any jitter left when the digital signal is finally sent to the soundcard, which of course has to be of high quality for passing the analog signal to a decent amp. No jitter, problem solved.

And then I don’t see why a normal CD player shouldn’t be able to do the same thing. Why shouldn’t it be able to correct the effects of jitter, when the PC is able to do it? Because bit-wise identical copies are possible (try it), and therefore you definitely are able to get a “perfect” digital copy of the original disc into your PC, otherwise you couldn’t burn an identical copy of it, what you actually can. And when you’ve once saved it to your hard disc, it is still identical, and when you start to play it back, the clock signal for playback is generated from the sound card, and every sample is played back in the perfectly right moment -> no jitter -> perfect sound from the soundcard.

But I can’t prove it yet, admitted. I found a very detailed article from a scientist on how to measure jitter, but unfortunately he did not mention at all if jitter has any impact on the sound… :rolleyes:

I am aware that the Hifi industry spreads lots of seemingly reasonable arguments why this or that is better, and many of them are just b*sh if you take a closer look at them with the necessary background knowledge. Unfortunately, the jitter question is very complex, so I can’t disprove it. Yet. :wink:


#14

Lord Voldemort> The noise inside of your PC case produced by the powersupply and any other components is so big that a normal portable CD-Player has less noise. The data is digitally correct. Its the same 100010001111001 or what ever is on the CD when it gets to the D/A (omiting scratched discs or any other errors which could occure). The problem is the noise affecting the analog data. Some even say that the noise can have an influence in burning quality and in readback quality corrupting the digital data. So in my oppinion the only point where the sound changes is after the D/A conversion.
Yes the Hifi industry spreads a lot of BS. Like speaker cables costing around 50$/m or more which are nothing less than shielded 99.999% High Class Oxygen-Free Copper (Hi-OFC) lines. Now elctrical lines in your wall or phone lines (yes the one with which you connect the phone to the walloutlet) in some countries are also 99.999% Hi-OFC but cost much less…And if you know how to shield (earth) a cable you can save a lot of money. The only problem is that the phone lines could burn through when too much power is sent to the speakers (although never happened to me).


#15

@Lord: Yes, I fully agree with you. If you copy the cd to your hard disk and then send it to the soundcard, the original jitter has no more relevance. I even think that most cd players would have a sort of buffer where the bit stream is queued so there should be no effect of jitter, at least not resulting from reading the cd. (Of course there are “new” sources for jitter, e.g. the bus clock). Maybe most home cd players don’t have a buffer or some do and others don’t, that might be the reason why with some cd player, you can clearly hear a difference… who knows?
However, somewhere in the whole chain you have a transition from the time pattern of the cd stream and the time pattern of the clock generator, and exactly at this transition, jitter is an issue.
I remember someone saying that - no matter where the jitter arises - it propagates along the whole chain and causes “noise” in the analog part.
I think it still depends on the inner architecture of the cd player, how good this noise is decoupled from the analoge signal.


#16

Meanwhile I understand your sorrows concerning jitter. :wink:
I don’t have much time at the moment, but sooner or later I’ll try to look up how a typical CD player is constructed, in order to find out if and to which degree jitter is really a problem. - No offense meant, I just want to really understand what happens in a CD player. It is a device that has always fascinated me. :wink:

Well, no, I don’t believe that. As you said, that depends on how the player is constructed.

  • You’re right: if a CD player has a buffer that temporarily stores the data, the jitter should be gone. And the clock generator for the buffer and the D/A converter shouldn’t produce new jitter, because the buffer sends the data perfectly in sync with the clock signal to the D/A converter, simply because the buffer will be triggered by the clock signal.
    So if the data is read correctly into the buffer, everything will be fine.

  • Concerning CD audio output via CDROM drive and soundcard: take the digital output. There can’t be significant jitter in the signal, and noise isn’t an issue anymore either.

Hm, this is actually quite interesting, this whole topic. :slight_smile:
You must know: I’m studying electrical engineering, and therefore I have a natural interest in such stuff. :wink: The problem is that one usually don’t learn too much about real world implementations like CD players during one’s studies. :frowning:


#17

Many highend CD Transporters (20000 US$) (players where the D/A (11000 US$), power supply (included with transporter) and clock generator are external) and Players are specially designed to minimize the affection of noise generated by the power supply.
About the Clockgenerator: Super highend systems use a external Word-Clock (using Rubidium) which is then attached to the Transporter (CD reader without D/A) and to the D/A itself to keep the clock right. Such a clock generator only can cost around 1.2million Yen (about 11000 US$). So all in all 42000US$. Well some audiophiles will pay this price tag and may add a Amplifier for another 7000 US$ and pinpoint foots (insulators for the equipment to place under the player) for 300US$/3 pack and 2000US$ for the power cable to conect Transport with power supply and some other 1000s for Audio plugs, I-Link cables to conect transport with D/A, speaker cables and cables to conect Clock generator with D/A and transport and many 1000s more for Speakers etc etc lol…
Btw it is said that a copy burned with a PMCD (A burner for Pre-Mastering like SONY CDU948 or CDW900 or Plextor PLEXMASTER) enabled writer which later gets pressed will nearly sound the same like the original (you cant hear difference in comparrison to the original). Well if this is true then CD-Rs cause some anomalies in the player itself (like more laser power / focusing problems to read leading to more noise or other things).
I myself did a blind test with some friends and we came to following conclusions:

  1. CD-Rs sound different than the original
  2. CD-Rs burned with 4 different burners (Sony, Yamaha, Plextor and Lite-On) using same batch of TY (8X Media to allow best possible compatibility with all Drives) and same source sound different (Copy done on the fly to multiple external SCSI recorders at 2x writing speed since 2x was the speed all burners could handle)
  3. Different Players sound different (well I think thats clear).
    Players used where 1 middle end CD-player (Marantz), 1 DVD Player (Pioneer) and 1 SACD Player (Sony) all from different makers connected to 1 Amplifier.

#18

The fact that this stuff is built and sold does not mean that it makes any sense from a technial point of view. :wink:
The industry makes up reasons why this or that is better that sound reasonable to most potential customers, but which are just nonsense.

I myself did a blind test with some friends and we came to following conclusions:

  1. CD-Rs sound different than the original

Could you please describe more detailed how you did that blind test? E.g.:

  1. When did you play which discs?
  2. Did anybody know that he’s listening to a CD-R or an original?
  3. Which statements did you make about what you’re listening at? Did you say “This is a copy” or “This is an original”, or what?

The problem with this test is that you haven’t checked if the CDs were burnt properly (at least I assume so?). A C1/C2 error scan would have been necessary, because a badly burnt CD-R will indeed sound different than the original.


#19

Ok, but just to draw a short conclusion to the original question; that means that it is indeed possible that VARIREC influences the sound. To be more precise, it does not influence the sound “OF THE CD”, but the sound “OF THE CD-PLAYER” which plays that cd… Maybe with a specific setting you can improve the acceptance of a copy for player A but you may lose it completely for player B at the same time…

There are too many factors that play a role in this matter. I even think it is too complicated to draw direct conclusions. But I swear I did hear differences when playing one commercial cd and its copy on one and the same player.


#20

Lord Voldemort>
Yes I agree with you on that Hifi audio makers will sell you many different BS without real evidence that this will get you high quality sound. There is a placebo effect with listening to music and makers will use that when selling players/cables/speakers etc.
If you have a blind folded person sitting infront of a pair of 1000 US$ speakers and a pair of 200US$ speakers and playback a cd on the 200US$ speakers and tell him that he is now hearing the sound of the 1000$ speakers and after that you play back the same track on the 1000$ speakers and tell him that now he is listening to the 200$ speakers he most likely will tell you that the speakers which he thinks are the 1000$ ones but in reality are the 200$ ones sound better…
About the blind test:
I have posted about this blind test at CDfreaks in the past and will search for that specific post and will post it here in this thread as soon i have found it.