Using a modern type of optical disc such as Blu-Ray — given its high storage capacity — it seems to me that an extremely high-bandwidth analog audio encoding scheme could be developed for it (possibly surpassing the bandwidth of the 2-inch tape that is traditionally used for analog master recordings).
The master tracks and master mixes could be recorded on hard drives using the same (or superior, given their even larger capacities) analog audio encoding scheme.
An analog optical disc would have the benefits of digital media (e.g., audio CDs), such as random access, contactless playback, and suitability for playback in portable hardware (e.g., in a vehicle); and none of the drawbacks of vinyl records, such as having to flip them over to hear them in their entirety, wear & tear resulting from normal playback, inevitable "coloration" of the audio to one degree or another by the needle/tonearm, cleaning requirements, and lack of portability.
Since digital audio data has to be converted to analog eventually in order to hear it (i.e., in order to drive speakers), and it is analog when it is created, it seems like the best approach would be to leave it in an analog format for the entire chain; as opposed to analog --> digital --> analog as is the chain of a typical audio CD (or analog --> analog --> digital --> analog for older recordings that get digitally remastered for release on CD).
The master tracks and master mixes could be recorded on hard drives using the same (or superior, given their even larger capacities) analog audio encoding scheme.
An analog optical disc would have the benefits of digital media (e.g., audio CDs), such as random access, contactless playback, and suitability for playback in portable hardware (e.g., in a vehicle); and none of the drawbacks of vinyl records, such as having to flip them over to hear them in their entirety, wear & tear resulting from normal playback, inevitable "coloration" of the audio to one degree or another by the needle/tonearm, cleaning requirements, and lack of portability.
Since digital audio data has to be converted to analog eventually in order to hear it (i.e., in order to drive speakers), and it is analog when it is created, it seems like the best approach would be to leave it in an analog format for the entire chain; as opposed to analog --> digital --> analog as is the chain of a typical audio CD (or analog --> analog --> digital --> analog for older recordings that get digitally remastered for release on CD).
Some of the LaserDiscs that had analog audio had good sound quality (the quality varied though, depending on the quality of the player and/or the mastering), and that was on an old format which only had the data density of a CD, and having to share space with video and several other audio channels (sometimes both analog and digital).
I don't see how dynamic range and linearity cababilities have anything to do with the fact that the audio information is being read by a laser. Shouldn't those be properties of the audio information itself?
Edit: I didn't word that well. Those properties would be determined not only by the audio information itself, but also by the laser's ability to read it accurately, and the quality of the output circuitry.
LaserDiscs had random access, even when used with the analog audio tracks (and originally they only had analog audio tracks). I don't know exactly how it was accomplished.
I'm thinking LaserDisc audio on steriods, due to exponentially greater capacity to work with (this allowing extreme bandwidth).
I don't see how dynamic range and linearity cababilities have anything to do with the fact that the audio information is being read by a laser. Shouldn't those be properties of the audio information itself?
Edit: I didn't word that well. Those properties would be determined not only by the audio information itself, but also by the laser's ability to read it accurately, and the quality of the output circuitry.
LaserDiscs had random access, even when used with the analog audio tracks (and originally they only had analog audio tracks). I don't know exactly how it was accomplished.
I'm thinking LaserDisc audio on steriods, due to exponentially greater capacity to work with (this allowing extreme bandwidth).
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I like the idea of those too, except you still have some of the disadvantages of vinyl records (e.g., having to keep them extremely clean, lack of portability, and I assume you still have to flip them to hear both sides). And of course, they are extremely expensive. They maintain a niche market though, and according to Robert Orban and Greg Ogonowski (from their article Maintaining Audio Quality in the Broadcast Facility):
Additionally, vinyl records are limited with regard to their potential accuracy relative to the source (the "acetate"). The acetate goes through various metal coating processes to get to the "stamper" stage, which results in some degree of loss.
Yes. Originally they only had analog audio, and later they had both analog and digital audio. They had analog video too.
I think that they should define an analog format for blu-ray. It doesn't have to be linear in amplitude, just time. That would allow a FM based analog format. And to take care of timing variations due to rotation, there could also be a digital track which could have time base information, as well as standard types of digital track info, etc.
If this blu-ray audio standard was specified so that it could be practically implemented in both record and playback with vacuum tube circuitry up to the laser record/playback diode, then that would be close to being a 'best of all worlds' format. And after a few years or a decade, when everybody is streaming their digital video from online or storing it in solid state memory instead of using a moving media format, blu-ray as a format would be still in business because of analog.
Well, I can always hope, can't I?
If this blu-ray audio standard was specified so that it could be practically implemented in both record and playback with vacuum tube circuitry up to the laser record/playback diode, then that would be close to being a 'best of all worlds' format. And after a few years or a decade, when everybody is streaming their digital video from online or storing it in solid state memory instead of using a moving media format, blu-ray as a format would be still in business because of analog.
Well, I can always hope, can't I?
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I think that DSD is the closest thing to "analog modulation" (with a spread spectrum carrier but descretized amplitude & zero crossing times) that can be encoded given the tweaking of the media&players for digital storage/retrieval
a big question is why anyone would want to go with mechanical timing for audio today:
"Every analog magnetic recording starts with a motor dragging a rusty strip of plastic over various rollers and guides, and across scraping metal parts. Unfortunately, every inconsistency in the speed of the tape as it traverses this obstacle course serves to distort the music being recorded. The transport's various imperfections create an ever-changing matrix of speed variations, slow or fast, subtle or severe. At worst, this results in the familiar warps and warbles known as "wow" and "flutter." It can even (as in the famous case of Miles Davis' "Kind of Blue") cause a perceptible tuning change over time.
Even the very best analog recordings are affected by varying and shifting patterns of constantly overlapping high frequency flutters, causing random beat frequencies to be introduced... all of which seriously interferes with the natural harmonic structure of the musical material.
"
Plangent Processes
spinning disks still have this problem - the optical head has a radial tracking servo and IMD at the DVD rotation frequency will be bigger in a "pure analog" encoding than it is in buffered PCM where even today some rotation speed IMD is sometimes still visible, even with digital fifo/reclocking (although this might be ps/motor/servo current coupling to the crystal)
a big question is why anyone would want to go with mechanical timing for audio today:
"Every analog magnetic recording starts with a motor dragging a rusty strip of plastic over various rollers and guides, and across scraping metal parts. Unfortunately, every inconsistency in the speed of the tape as it traverses this obstacle course serves to distort the music being recorded. The transport's various imperfections create an ever-changing matrix of speed variations, slow or fast, subtle or severe. At worst, this results in the familiar warps and warbles known as "wow" and "flutter." It can even (as in the famous case of Miles Davis' "Kind of Blue") cause a perceptible tuning change over time.
Even the very best analog recordings are affected by varying and shifting patterns of constantly overlapping high frequency flutters, causing random beat frequencies to be introduced... all of which seriously interferes with the natural harmonic structure of the musical material.
"
Plangent Processes
spinning disks still have this problem - the optical head has a radial tracking servo and IMD at the DVD rotation frequency will be bigger in a "pure analog" encoding than it is in buffered PCM where even today some rotation speed IMD is sometimes still visible, even with digital fifo/reclocking (although this might be ps/motor/servo current coupling to the crystal)
I think the primary reason is that the discrete process of A/D/A conversion ( the so-far intractable bugaboo of digital where real world precisions exceeding 18 bits quantization monotonic without missing codes are extremely rare) is completely sidestepped by keeping the process analog. As could be the typical RF contamination problem endemic with almost all digital equipment. Also, SQ restrictions due to standardized word length and quantization rate limitations are no longer relevant.
Then, it should go without saying that the amplitude of speed and vibration variations during the record and playback process can be continually reduced as the mechanisms are refined. Who knows, maybe somebody will come up with a method of recording and playing blu-ray media where the disc does not move at all and all motion of the record/playback beam is handled with optical precision which has already been refined to precisions of far better than parts per million.
Then, it should go without saying that the amplitude of speed and vibration variations during the record and playback process can be continually reduced as the mechanisms are refined. Who knows, maybe somebody will come up with a method of recording and playing blu-ray media where the disc does not move at all and all motion of the record/playback beam is handled with optical precision which has already been refined to precisions of far better than parts per million.
It's still made up of pits and lands of 1's and 0's, how analog can that be.
Laserdiscs are an interesting format. The information is analog, PWM. An FM signal is created from the analog original. The signal is chopped so it resembles a square wave of varying widths and sizes. This is made into the pits on the disc.
A web search could probably turn up a better explanation. I don't see why any optical disc couldnt hold data this way. Thing is you'd need your own way of encoding and decoding the disc.
A web search could probably turn up a better explanation. I don't see why any optical disc couldnt hold data this way. Thing is you'd need your own way of encoding and decoding the disc.
This all assumes that you'll be able to record and read the information with better resolution than an 18-22 bit digital sampled signal, which isn't really technically feasable. You're also giving up error correction, time and pitch synchronization, and a bunch of other things you can do more easily with a digital signal.
In short, I don't think it would be hard to do, but there appears to be almost no demand for it considering it's not easier to implement, it's not more compact than digital for the same information stored, and there's so little interest in hi-fi sound in general.
John
In short, I don't think it would be hard to do, but there appears to be almost no demand for it considering it's not easier to implement, it's not more compact than digital for the same information stored, and there's so little interest in hi-fi sound in general.
John
I think the real standard is not the storage resolution by itself but the limitations of both the A/D and D/A processes in real world equipment and sadly, one or both are markedly inferior SQ speaking (seldom if ever over 16 bit at best in the aggregate, usually significantly less), to good analog 99+% of the time. There's little point in merely focusing on wide word lengths and high sampling rates (which we really don't even have any more with the demise of SACD and DVDA) and completely ignoring the fact that SQ is virtually always significantly compromised in real world equipment during the A/D/A conversion processes. That's a major factor that contributed to a generation of what I consider ruined recordings starting with the 'perfect sound forever' CD hoopla.
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Something I have wondered, and would like to try:
COULD it be possible to make a CD-R writer create (on a normal CDR) a disc that a Laservision player will play?
You'd have to convert an AVI file into some digital variant that 'looks' like analogue video, and is still compatible with what you can dump to a CDR drive.
COULD it be possible to make a CD-R writer create (on a normal CDR) a disc that a Laservision player will play?
You'd have to convert an AVI file into some digital variant that 'looks' like analogue video, and is still compatible with what you can dump to a CDR drive.
The pits and lands don't represent 1s and 0s on a LaserDisc's analog audio track. There is a brief explanation here.
Are we going down the analog/digital rat-hole again.... 
As much as I love my vinyl, I think we are at that point with modern 24/192 systems where analog recording no longer makes any sense. Delta-sigma A/D systems have extremely high dynamic range and beyond 18 bits.
Yes SACD and DVDA is dead as has been pointed out, but it has been replaced by high resolution systems on BLUE-RAY which will have better penetration.
Alvaius
As much as I love my vinyl, I think we are at that point with modern 24/192 systems where analog recording no longer makes any sense. Delta-sigma A/D systems have extremely high dynamic range and beyond 18 bits.
Yes SACD and DVDA is dead as has been pointed out, but it has been replaced by high resolution systems on BLUE-RAY which will have better penetration.
Alvaius
24/192, I'm guessing if nobody can tell a difference between that and say 20/96, there is no push for further development. Video, on the other hand, there's never enough pixel or bitrate. But we're still stuck with 24/32-bit color.
Sometimes I wonder a good DAC vs LP, which will give better value.
But I guess an apple-to-apple comparison isn't possible with everything being mastered digitally nowadays. I'm guilty of listening to synthesized music.
Sometimes I wonder a good DAC vs LP, which will give better value.
But I guess an apple-to-apple comparison isn't possible with everything being mastered digitally nowadays. I'm guilty of listening to synthesized music.
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While I agree, the industry has chosen digital and its here to stay, also I don't think we'll be seeing any new formats anytime soon.
The thought exercise has given me an idea. If we were starting from scratch why couldnt we make an analog format using high bandwith PWM? The "bitrate" could be compatible with a class D type amp, set up at a similar rate. The PWM data could be read directly off the disc and fed real time to the amp, right to the speakers. Shortest signal ever possible?
The thought exercise has given me an idea. If we were starting from scratch why couldnt we make an analog format using high bandwith PWM? The "bitrate" could be compatible with a class D type amp, set up at a similar rate. The PWM data could be read directly off the disc and fed real time to the amp, right to the speakers. Shortest signal ever possible?
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