Re: [luv-talk] Playing LP's with a laser pickup ?
Exact citation thanks toDavid I believe the device described and sold at the URL below is real; I was really just exploring whether 1/ anyone had every had any experience with such and 2/ whether any other varieties existed regards Rohan I don't have any reason to doubt that $15k+ device is/was real. I expect some hackers could make their own LASER pickup for a turntable for less than $500-$1000. (Maybe less than $50, I dunno.) My only doubt is whether an UNMODIFIED LaserDisc player could really play UNMODIFIED LPs. The audio and video on LaserDiscs was analog but span much faster than 33 1/3 RPM. A C.onstant A.ngular V.elocity Disc for PAL would spin at 25 revs per SECOND = 1500 RPM as each track held one video frame. (30RPS = 1800 RPM for an NTSC disc.) So for a start, the sound would have to BE buffered, say by writing to & replaying from a computer file, otherwise the treble section would be ultrasonic & only microscopic creatures could dance to the beat! The Wikipedia LaserDisc article is pretty comprehensive. In referring to LASER Rot however, it doesn't mention that apparently the metal recording surface was exposed at the outside edge, which I read back then made the discs more vulnerable than CDs etc. It also doesn't mention a reason for adopting a smaller form-factor for the Digital A.udio D.is(c or k?) standard which became the Compact Disc. Manufacturers wanted to make a player that would fit in the standard car radio/cartridge/cassette dashboard space. (There was a least one phonograph produced for cars I think.) I would have liked to see the "Soundstream Audio File" system adopted as the DAD standard but there wasn't much chance of a little company beating the winning alliance of Philips & Sony. The article reference 14 in http://en.wikipedia.org/wiki/Soundstream is not available at http://www.eetimes.com/ but basically AudioFile, VideoFile & DataFile used a photographically reproducible optical track read by an orbiting lens which swept past & tracked along the length of the rectangular card. (Or the card could have tracked past the lens but that's not how I remember it. Wouldn't affect compatibility either way.) Because the medium wasn't spinning, all the arc-shaped tracks were the same length, also the medium could be various lengths & potentially transparent so both sides could be played without flipping. (I read about AudioFile in an article by J. Hansen called "The Record that Doesn't Go Round" in January 1983 "Hi-Fi News & Record Review" magazine presumably still at the State library of Victoria. Maybe in the stacks now. I still had a photocopy not long ago, somewhere. Exact citation thanks to http://arpjournal.com/2140/soundstream-the-introduction-of-commercial-digita... )
Please ignore the first "Exact citation thanks to" part at the start of my previous post. (So that's where the cursor jumped to. Actually that bit's Rohan's post. ) Yahoo has really become behaviourally a Yahoo or maybe a Laputan with technical ambitions beyond their competence to do well. (Well I'm not going to blame MY incompetence!) If it wasn't for sunk costs & e-groups I'd treat "Yahoo" like "Facebook". (Is that thing still around? I gather it became quite popular!) On , David E Payne <spyder.king@yahoo.com.au> wrote: Exact citation thanks toDavid I believe the device described and sold at the URL below is real; I was really just exploring whether 1/ anyone had every had any experience with such and 2/ whether any other varieties existed regards Rohan I don't have any reason to doubt that $15k+ device is/was real. I expect some hackers could make their own LASER pickup for a turntable for less than $500-$1000. (Maybe less than $50, I dunno.) My only doubt is whether an UNMODIFIED LaserDisc player could really play UNMODIFIED LPs. The audio and video on LaserDiscs was analog but span much faster than 33 1/3 RPM. A C.onstant A.ngular V.elocity Disc for PAL would spin at 25 revs per SECOND = 1500 RPM as each track held one video frame. (30RPS = 1800 RPM for an NTSC disc.) So for a start, the sound would have to BE buffered, say by writing to & replaying from a computer file, otherwise the treble section would be ultrasonic & only microscopic creatures could dance to the beat! The Wikipedia LaserDisc article is pretty comprehensive. In referring to LASER Rot however, it doesn't mention that apparently the metal recording surface was exposed at the outside edge, which I read back then made the discs more vulnerable than CDs etc. It also doesn't mention a reason for adopting a smaller form-factor for the Digital A.udio D.is(c or k?) standard which became the Compact Disc. Manufacturers wanted to make a player that would fit in the standard car radio/cartridge/cassette dashboard space. (There was a least one phonograph produced for cars I think.) I would have liked to see the "Soundstream Audio File" system adopted as the DAD standard but there wasn't much chance of a little company beating the winning alliance of Philips & Sony. The article reference 14 in http://en.wikipedia.org/wiki/Soundstream is not available at http://www.eetimes.com/ but basically AudioFile, VideoFile & DataFile used a photographically reproducible optical track read by an orbiting lens which swept past & tracked along the length of the rectangular card. (Or the card could have tracked past the lens but that's not how I remember it. Wouldn't affect compatibility either way.) Because the medium wasn't spinning, all the arc-shaped tracks were the same length, also the medium could be various lengths & potentially transparent so both sides could be played without flipping. (I read about AudioFile in an article by J. Hansen called "The Record that Doesn't Go Round" in January 1983 "Hi-Fi News & Record Review" magazine presumably still at the State library of Victoria. Maybe in the stacks now. I still had a photocopy not long ago, somewhere. Exact citation thanks to http://arpjournal.com/2140/soundstream-the-introduction-of-commercial-digita... )
On Sat, 3/5/14, David E Payne <spyder.king@yahoo.com.au> wrote: Subject: Re: [luv-talk] Playing LP's with a laser pickup ? To: "luv-talk" <luv-talk@luv.asn.au> Received: Saturday, 3 May, 2014, 4:34 PM SNIP " The Wikipedia LaserDisc article is pretty comprehensive. In referring to LASER Rot however, it doesn't mention that apparently the metal recording surface was exposed at the outside edge, which I read back then made the discs more vulnerable than CDs etc. It also doesn't mention a reason for adopting a smaller form-factor for the Digital A.udio D.is(c or k?) standard which became the Compact Disc. Manufacturers wanted to make a player that would fit in the standard car radio/cartridge/cassette dashboard space. (There was a least one phonograph produced for cars I think.) I would have liked to see the "Soundstream Audio File" system adopted as the DAD standard but there wasn't much chance of a little company beating the winning alliance of Philips & Sony. The article reference 14 in http://en.wikipedia.org/wiki/Soundstream is not available at http://www.eetimes.com/ but basically AudioFile, VideoFile & DataFile used a photographically reproducible optical track read by an orbiting lens which swept past & tracked along the length of the rectangular card. (Or the card could have tracked past the lens but that's not how I remember it. Wouldn't affect compatibility either way.) Because the medium wasn't spinning, all the arc-shaped tracks were the same length, also the medium could be various lengths & potentially transparent so both sides could be played without flipping. (I read about AudioFile in an article by J. Hansen called "The Record that Doesn't Go Round" in January 1983 "Hi-Fi News & Record Review" magazine presumably still at the State library of Victoria. Maybe in the stacks now. I still had a photocopy not long ago, somewhere. Exact citation thanks to http://arpjournal.com/2140/soundstream-the-introduction-of-commercial-digita... ) " * * * * * * LaserDiscs & players are the subject of an episode of "Regular Show" to be repeated on TV Ch 99 at 12:30 tomorrow 2014 August 30th morning ie about 9 hours from time I'm posting this. (Like the somewhat similar but for me superior "Adventure Time", they show 2 eps in between the ads in a 30min time slot so the eps are probably ~9 mins long.)
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David E Payne