Re: MD: Found a CD that cannot be digitally recorded on MD
Andrew Hobgood wrote: | No, the LSB gets dropped and you still end up with a signal that will not | overflow the register. All that happens is you lose the extra 1 bit | resolution from the LSB end. And this is significantly different from "clipping" in what way? Loss of data is loss of data, no matter how you try to spin it. Well, clipping manifests itself as chopping the MSB (bit or bits, depending on the severity of clipping) because the incoming signal has a range far beyond the sampling range of the A/D converter. I just suddenly remembered something about digital sound data - the MSB is a sign bit. If you imagine a sine wave being fed into a system that chopped the MSB, i would turn into an 'm' shape. and it still wouldn't clip. -- Magic Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] "A book judged by it's cover makes for a very shallow read." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
I just suddenly remembered something about digital sound data - the MSB is a sign bit. If you imagine a sine wave being fed into a system that chopped the MSB, i would turn into an 'm' shape. and it still wouldn't clip. Are you sure? That format of the data depends entirely on the platform on which you're doing the data transfer... most computers (in PC PCM format) use signed word (16 bit) storage... though, some use unsigned word... *pondering* ahck. my head is broken. I can't figure out whether or not that'd make a difference. =P Although... if it is using signed word, and the sign bit gets dropped, if its using two's complement, it'll screw up the two's-complement conversion, and possibly throw off the data stream. /Andrew - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Andrew Hobgood wrote: I just suddenly remembered something about digital sound data - the MSB is a sign bit. If you imagine a sine wave being fed into a system that chopped the MSB, i would turn into an 'm' shape. and it still wouldn't clip. Are you sure? That format of the data depends entirely on the platform on which you're doing the data transfer... most computers (in PC PCM format) use signed word (16 bit) storage... though, some use unsigned word... *pondering* Minidisc uses 16bit signed audio data as input. Well that's what comes out of the S/PDIF anyway so I assume it must be part of the standard. ahck. my head is broken. I can't figure out whether or not that'd make a difference. =P Although... if it is using signed word, and the sign bit gets dropped, if its using two's complement, it'll screw up the two's-complement conversion, and possibly throw off the data stream. Just tried it using assembler the wave you end up with is really wierd looking. The sine wave starts off ok until the point where it goes negative - it then appears as a U shape at the top of the graph. You and up with something a bit like this (cue the poor ASCII art) __ nununununu __ where the underline represents 0 Sounds very strange too almost like a pulsing square wave.. very harsh...- it it was "clipping" this way you would really notice it. If the data was unsigned, you get a really odd wave that looks like this //\\//\\//\\//\\//\\ Sounds like everything is in a wierd echo tube strange might try and make a circuit to do this for the electric guitar, it's phreaky but cool -- Magic Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] "Creativity is more a birthright than an acquisition, and the power of sound is wisdom and understanding applied to the power of vibration." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
James Montgomerie wrote: Remember that 'clipping' is not the same as just losing a bit of data. also polite voice... although somewhat fed up of this thread because of its complete irrelevance to the actual problem There are many types of clipping. Register or data clipping is where bits of data are clipped from either end of a stream. The most common method for this is truncation where LSBs are removed. Waveform clipping occurs not in data transfer but in calculation such as applying digital gain through ,multiplication arrays, or adding data sets together. This type of clipping (the type we more commonly see via the "over" indicator is associated with the data registers going into an "Overflow" situation, where the number to be stored is too large for the register, resulting in a flag being set and the register (dependant on CPU) holding the maximum allowed value. Anyway, all this is academic, as TosLink should transmit the 16-bit data exactly as it receives it from a CD - it's /impossible/ (not just improbable, but impossible) that what is being discussed on this thread is caused by any form of 'clipping' or truncating of the data from the CD. Yes, I know, but Mr Rat seems to insist otherwise. I agree that there must be *something* causing his drop-outs, but it cannot be clipping. The only thing I can think of that would cause drop-outs in consistant places is a problem either with the S/PDIF output on the CD player being triggered by soething *or* errors on the CD which are enough to cause the S/PDIF output to "break", resulting in a drop-out, but which are not large enough for the ear to percieve the brief break in the signal on an analogue system. The drop-out may be smply because the MD needs to re-sync. P.S. the idea floating around about sign bits is probably also a red herring - there are MANY different ways to store a sign in binary, [and none of them is the 'right' one, though some are easier to handle than others]. Anyway, I would imagine (though I don't know - perhaps I need some polite correction too?) that MD uses a straight 16-bit positive binary number to store data, and doesn't dabble into any of this negative nastiness. I would imagine internally that MD uses straight 16 bit data, but the decoder chips I have supply signed 16bit data in 2s compliment form from S/PDIF input, so I presume that this is the standard. -- Magic Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] "Creativity is more a birthright than an acquisition, and the power of sound is wisdom and understanding applied to the power of vibration." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 * Magic [EMAIL PROTECTED] on Thu, 14 Oct 1999 | The peak amplitude is 0dB. "Infinity" -0dB. | There is no possibility of you ever going over 0dB because that would be | a clipped signal already. If "infinity" on unit A is higher than "infinity" on unit B, then signal that is below A's peak will be above B's peak. | There is no way you can represent a value over 0dB, it just can't happen, | the electronics wont allow it. Exactly. If you stuff a 17-bit number into a 24-bit register, there is no problem. But if you then take that 17-bit number and stuff it into a 16-bit register, you will overflow the register. [...] | Whatever is causing the symptoms is not clipping. The symptom is apparantly indistinguishable from clipping. If it walks like a duck -BEGIN PGP SIGNATURE- Version: GnuPG v1.0.0d (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE4BiP8gl+vIlSVSNkRAl6bAJ97u1FDl9S9c5lWjCEkjqdSegVmBgCgqiWh yOLvPhjmh6RO+l9ARGXc+Gs= =iTKu -END PGP SIGNATURE- -- Rat [EMAIL PROTECTED]\ Do not taunt Happy Fun Ball. Minion of Nathan - Nathan says Hi! \ PGP Key: at a key server near you! \ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Stainless Steel Rat wrote: Exactly. If you stuff a 17-bit number into a 24-bit register, there is no problem. But if you then take that 17-bit number and stuff it into a 16-bit register, you will overflow the register. No, the LSB gets dropped and you still end up with a signal that will not overflow the register. All that happens is you lose the extra 1 bit resolution from the LSB end. -- Magic Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] "A book judged by it's cover makes for a very shallow read." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 * Magic [EMAIL PROTECTED] on Thu, 14 Oct 1999 | No, the LSB gets dropped and you still end up with a signal that will not | overflow the register. All that happens is you lose the extra 1 bit | resolution from the LSB end. And this is significantly different from "clipping" in what way? Loss of data is loss of data, no matter how you try to spin it. -BEGIN PGP SIGNATURE- Version: GnuPG v1.0.0d (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE4BmpWgl+vIlSVSNkRAqITAKDahZeKSz+h1iJgQWojVyS3wPzAWQCg/wFc X4Yv7D/UkyYBfpjuvZigo2A= =Yf5R -END PGP SIGNATURE- -- Rat [EMAIL PROTECTED]\ When not in use, Happy Fun Ball should be Minion of Nathan - Nathan says Hi! \ returned to its special container and PGP Key: at a key server near you! \ kept under refrigeration. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
| No, the LSB gets dropped and you still end up with a signal that will not | overflow the register. All that happens is you lose the extra 1 bit | resolution from the LSB end. And this is significantly different from "clipping" in what way? Loss of data is loss of data, no matter how you try to spin it. Well, clipping manifests itself as chopping the MSB (bit or bits, depending on the severity of clipping) because the incoming signal has a range far beyond the sampling range of the A/D converter. Magic's LSB clipping would occur only if you're transferring digital data, and the frame copy routine is specified to maintain the MSB when discarding data. A poorly designed routine would accidentally discard the MSB instead of the LSB, resulting in a behavior that sounds much like clipping, but without the A/D stage that clipping is historically characterized by. This is all IIRC, so if I'm wrong, feel free to correct me politely. =P my $0.02, /Andrew - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Hannes Rohde wrote: That's true. Actually, it seems that quite a few commercially available cds are digitally clipped, at least that's what I read in one of those audiophile magazines... A lot of my cds seem to be that way - if I change the digital record level to even +0.1dB the over light is lit almost all the time. With the rec level at 0dB it doesent light nomatter how clipped the input is. Some even _sound_ clipped. -- Richard - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Graham Baker wrote: David Tamkin wrote: As I've learned here, all digital media are incapable of representing amplitudes over 0 dB, and digital recordings must be scaled accordingly. That's true in theory but in practice Sony seem to have allowed for user-error by somehow incorporating a kind of 'soft clipping' to (analog) record levels that go over 0dB. My JA3 allows quite a lot of 'in the red' levels before you can hear any nasties GB As far as I know they use a compressor which takes anything in the -2dB to +4dB range and compresses it into -2dB to 0dB. -- Magic Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] "A book judged by it's cover makes for a very shallow read." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 * Magic [EMAIL PROTECTED] on Wed, 13 Oct 1999 | You can't have a digital source that loud because the absolute highest | amplitude you can store is 0dB. My understanding of it is that "0dB" is actually "infinity - 0dB", where "infinity" is the biggest number the recorder can handle (kinda like MAXINT). If oo - 0dB on the CD is greater than oo - 0dB on the recorder, then clipping can happen. It is not supposed to happen, but it does appear to be happening. The ~90 other CDs I have copied with the same hardware sound fine. Analog playback of the CD in question sounds fine. An analog recording of the CD sounds fine. Clipping only happens when I make a digital copy of that particular disc, and it happens with both Sony and Sharp recorders. Go fig. -BEGIN PGP SIGNATURE- Version: GnuPG v1.0.0d (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE4BTNNgl+vIlSVSNkRAksTAJ9YOKNtEjOlvBL+lqQ7P4BuLDTsWwCeN/Ow nkGdadBpd41NoSs5kRPtO/Q= =pUcY -END PGP SIGNATURE- -- Rat [EMAIL PROTECTED]\ Do not use Happy Fun Ball on concrete. Minion of Nathan - Nathan says Hi! \ PGP Key: at a key server near you! \ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
The inoxidizable rodent asked, | What would happen if the record level on the masters from which the CDs | were pressed was set higher than the allowed threshold (ie, 'OVER' on my | 702's display) for CD media? Then the CD would have already been spoiled by clipping in the process of making a digital master for the CD, those passages would sound clipped when you listen to the CD, and a digital copy to MD at unity gain would faithfully preserve the sound as already clipped. As I've learned here, all digital media are incapable of representing amplitudes over 0 dB, and digital recordings must be scaled accordingly. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
SSR asked: | What would happen if the record level on the masters from which the CDs | were pressed was set higher than the allowed threshold (ie, 'OVER' on my | 702's display) for CD media? At 01:05 PM 10/12/99 -0500, DWT wrote: Then the CD would have already been spoiled by clipping in the process of making a digital master for the CD, those passages would sound clipped when you listen to the CD, and a digital copy to MD at unity gain would faithfully preserve the sound as already clipped. As I've learned here, all digital media are incapable of representing amplitudes over 0 dB, and digital recordings must be scaled accordingly. Not necessarily. I have a few CDs which light OVER on digital record and then when played back. I suspect OVER just means the sample was +16383 or -16384. No audible clipping is heard. +16383/-16384 is not an invalid sample in itself. But obviously, unless the recording has been digitally scaled, it is likely that this sample value would mean clipping. -- Archer http://www.geocities.com/SoHo/6413/ End. - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Rat wrote, | This is not a copy protection issue. It appears that the first disc of the | Blue Oyster Cult "Workshop of the Telescopes" collection has the recording | level set just high enough to cause occasional "drop-outs" in the digital | MD copy. This happens on both my MD-MS702mk and MZ-R30. That doesn't compute. The CD player should still be putting out a digital signal, just as it does between tracks or during caesuras. Maybe there's something wrong with the CD player that it can't read those spots on the CD, or wrong with the CD at those places, or wrong with the MD platter at the places where those passages were to be written to it (if Rat was trying to record from the beginning of the CD to the same MD in the 702mk as in the R30). Rat, are you listening to the CD while you copy it? Can you hear the music through the CD player's DAC at those spots? Can you hear it through the MD recorder's DAC while it is recording the places where you get dropuots? It just doesn't sound logical that the CD player can send the data of an audible signal to its own DAC but the data of a silent signal to its digital output jack. Hmm. Maybe it can convert the PCM from the CD to analog audio, but it messes up converting it to S/PDIF? - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 * [EMAIL PROTECTED] (David W. Tamkin) on Mon, 11 Oct 1999 | That doesn't compute. The CD player should still be putting out a digital | signal, just as it does between tracks or during caesuras. I know. That is what has me baffled. It makes no sense, but there is definitely something wrong, here. I suppose "dropout" is not entirely accurate. It feels (rather than sounds) as if the record level on the CD signal might be so high that MD recording circuit cannot deal with it, so it throws it out, leaving a "glitch" in the MD playback. It is difficult to describe something that is not there. The other thought I have is that because the CD in question is very "bass heavy" it is overloading the lower-end ATRAC time-frequency units. MP3 is susceptible to this (try listening to Prince's "Raspbery Beret" encoded with MP3), but I do not believe that ATRAC has this problem. | Maybe there's something wrong with the CD player that it can't read those | spots on the CD, I have had no problem with the CD player (Pioneer PD-F606, TOSlink directly into to the recorder) with the ~90 other MDs I have recorded this way. | or wrong with the CD at those places, This is what I believe might be the case, except that it sounds okay when I play it back through my amplifier. | or wrong with the MD platter at the places where those passages were to | be written to it (if Rat was trying to record from the beginning of the | CD to the same MD in the 702mk as in the R30). Same original CD and player, different recorders, different MDs, same problem. Though to be honest, it is worse on the 702mk. I originally thought it might be a problem with Sharp's ATRAC, but I had similar results on the Sony unit. Quite strange, indeed. -BEGIN PGP SIGNATURE- Version: GnuPG v1.0.0d (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE4AjGegl+vIlSVSNkRAv2dAJ4wdUJVNwR4F1gR1It/o5Y71leh4ACg5Osj uc1vji/peNwpiGtPs2UG3XI= =1Cfq -END PGP SIGNATURE- -- Rat [EMAIL PROTECTED]\ Happy Fun Ball may stick to certain types Minion of Nathan - Nathan says Hi! \ of skin. PGP Key: at a key server near you! \ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Stainless Steel Rat wrote: Same original CD and player, different recorders, different MDs, same problem. Though to be honest, it is worse on the 702mk. I originally thought it might be a problem with Sharp's ATRAC, but I had similar results on the Sony unit. The Sharp 70x series have a known problem with some bass sounds, resulting in strange distorted sounds or clicks at critical passages. Sony units should not be affected by this, though... Maybe you have discovered a bug in Sony's Atrac algorithm? Bye, Hannes - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Stainless Steel Rat wrote: This is not a copy protection issue. It appears that the first disc of the Blue Öyster Cult "Workshop of the Telescopes" collection has the recording level set just high enough to cause occasional "drop-outs" in the digital MD copy. This happens on both my MD-MS702mk and MZ-R30. Has anyone else ever experienced anything like this? If this is the same release of the album I have (Columbia label - 480949-2) it's not a volume issue. I've just copied it digitally from a Marantz CD-48 CD player to my Sony R55, and there are no drop-outs, distortions or clipping. -- Magic Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] "A book judged by it's cover makes for a very shallow read." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
Stainless Steel Rat wrote: * Magic [EMAIL PROTECTED] on Mon, 11 Oct 1999 | If this is the same release of the album I have (Columbia label - | 480949-2) it's not a volume issue. Nope. It is a 2-disc set, Columbia/Legacy C2K-64163. So I'm still not absolutely certain it is not a volume issue. 2CD set. CD 1 - 15 tracks, CD 2 - 17 tracks. Anubis (dog-like statue of ehyptian origin) perched on an alter with the BOC logo on it. CD 1 is yellow with a bloue middle, CD 2 is blue with a yellow middle. Even if the cover varies slightly I would expect the CD content to be the same. Volume issues would not cause drop outs anyway - the only thing that would cause drop-outs is an interruption in the S/PDIF output, or corrupted SCMS information causeing small fragments of the disc to be "unrecordable". -- Magic Location : Portsmouth, England, UK Homepage : http://www.mattnet.freeserve.co.uk EMail : mailto:[EMAIL PROTECTED] "A book judged by it's cover makes for a very shallow read." - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
Re: MD: Found a CD that cannot be digitally recorded on MD
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 * Magic [EMAIL PROTECTED] on Mon, 11 Oct 1999 | If this is the same release of the album I have (Columbia label - | 480949-2) it's not a volume issue. Nope. It is a 2-disc set, Columbia/Legacy C2K-64163. So I'm still not absolutely certain it is not a volume issue. -BEGIN PGP SIGNATURE- Version: GnuPG v1.0.0d (GNU/Linux) Comment: For info see http://www.gnupg.org iD8DBQE4Am4Bgl+vIlSVSNkRAnZqAJ4w6KL2sp7NVu2HIVWhTDigH8CyMACgxA6F 6RKgYluHdXIXdPPVYyIvP7E= =vdA3 -END PGP SIGNATURE- -- Rat [EMAIL PROTECTED]\ Happy Fun Ball may stick to certain types Minion of Nathan - Nathan says Hi! \ of skin. PGP Key: at a key server near you! \ - To stop getting this list send a message containing just the word "unsubscribe" to [EMAIL PROTECTED]
