Let's cheat with sound!

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Let's cheat with sound!

Postby Viewmaster » Sat Jul 14, 2007 11:09 pm

Problem with sound and picture on a Edikow machine can be easily solved by cheating. :) ....or bringing the old to interface with the new.

Put the picture on the cylinder as we discussed and put the sound on a CD as per existing NBTV standards...on the right channel.

Get the Edikow machine up to correct speed and have a marker on the left channel of the CD which lowers the playback mechanism onto the cylinder.
OR,easier still, start the picture on the cylinder running and, say, 2 seconds before images begins there is a white flash marker (as on film changover flashes) on the NBTV picture.

This is the signal to hit the start button on the CD, the flash being early by ones own reaction timing.
The rest of the left CD channel can be used for other things if need be...like announcing to the wife to put the kettle on for tea! :lol:
Comments please.....no rudeness allowed.
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Postby Andrew Davie » Sat Jul 14, 2007 11:18 pm

I really don't like this idea, sorry. Nor do I feel that using cylinders is the way to go. Baird was experimenting with Phonovision -- the recording of video and images on 'normal' phonograph records. In fact, we now know that his technology was fundamentally sound (excuse the pun!)... because we have recently seen VinylVideo showing quite extraordinary picture quality.

I think the best thing to do would be proceed with Baird's original concept -- that is, recording NBTV on a flat phonograph record. My goal would be to have a record that could be played on just about any normal record player -- anything with an electronic output, and use that as the input for the NBTV circuits.

All this talk about cylindrical Edison-type recording is interesting, but in my opinion just way off the mark. The cylindrical record was long gone by the time that Baird was experimenting with recording onto records. I don't see why we should resurrect them -- they have way-too-short playback times, which would immediately rule them out in my reckoning.

I do like the idea of extrapolating the technology to create a sort of modern-day alternate technological reality for (say) the 1930s. Edison cylinders aren't in that reality, IMHO. And anything that requires a CD is, also, not something that really should be there, either.
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Audio/video recording.

Postby Stephen » Sat Jul 14, 2007 11:24 pm

Since it seems that even eighty years after Mr. Baird's proposal to utilise a single two-channel groove for audio and video that such recording seems to be beyond the capabilities of 21st century technology, perhaps we should consider the two discrete track approach. An American company, Cook Laboratories, did this in the early 1950s with stereo LPs. See an illustration of this at http://online.sfsu.edu/~hl/s.html . Using microgroove recording, we would have enough playing time to divide up the cylinder or disc into audio and video portions and still have a reasonable length audio/video recording.
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Postby Viewmaster » Sat Jul 14, 2007 11:33 pm

Thanks for all the considered comments..much appreciated.

In 1877 Thomas Edison invented the phonograph using a cylinder of tin foil. But a short 6 years later in 1883 Paul Nipkow invented the scanning disc.

If these two men had ever met they may well have discussed bringing their ideas together to build a Edikow machine.
That is a bit of history that never was, and I am determined to build such a machine even if the picture is crappy.....as I know it will be.

I bet many NBTV owners would like to see what type of pictures would be possible from an Edikow...I certainly would.

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Another recording techique.

Postby Stephen » Sat Jul 14, 2007 11:52 pm

It might be possible to record a hill-and-dale groove in the following manner. Take a high power modulated light source, such as an array of LEDs, and focus the modulated light therefrom into a small spot onto the recording surface. The spot of light would obliterate the recording surface under the spot to a depth that varies in accordance with the intensity of the modulated light. This would create a hill-and-dale modulated groove in the recording surface.

It would be important to choose a recording medium that is not flammable to avoid the inconvenience of keeping a fire extinguisher on hand. I think that lacquer recording discs may therefore not be suitable candidates. However, Fimo and perhaps some waxes may be suitable.

A conventional stylus, or better yet, the Bell-Tainter air jet, may reproduce the hill-and-dale modulated groove.
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Postby M3DVQ » Sun Jul 15, 2007 12:04 am

Andrew Davie wrote:I think the best thing to do would be proceed with Baird's original concept -- that is, recording NBTV on a flat phonograph record. My goal would be to have a record that could be played on just about any normal record player -- anything with an electronic output, and use that as the input for the NBTV circuits.


This has been done! Jeremy Jago demonstrated a record that he had received from a friend overseas, containing NBTV club signals, that he played into a CRT display from a standard portable record player!
http://www.nbtv.wyenet.co.uk/dscn3234.jpg
http://www.nbtv.wyenet.co.uk/dscn3256.mov
both from the 2006 convention page http://www.nbtv.wyenet.co.uk/c06jago.htm
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Re: Another recording techique.

Postby Viewmaster » Sun Jul 15, 2007 12:09 am

Stephen wrote:It might be possible to record a hill-and-dale groove in the following manner. Take a high power modulated light source, such as an array of LEDs, and focus the modulated light therefrom into a small spot onto the recording surface. The spot of light would obliterate the recording surface under the spot to a depth that varies in accordance with the intensity of the modulated light. This would create a hill-and-dale modulated groove in the recording surface..


Now that is a brilliant idea if it works, because it is something that would be relatively easy for us to make. We have ultra bright LEDs to hand, so all we need is a very very powerful focusing lens taking the LED array down to a few thou of an inch.
Stephen wrote:It would be important to choose a recording medium that is not flammable to avoid the inconvenience of keeping a fire extinguisher on hand. ..


I like that. All dressed up in fireproof suits with safety googles on and a bucket of water to hand....much better that slumped in an armchair watching modern HDTV.
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Optical cutter.

Postby Stephen » Sun Jul 15, 2007 12:11 am

One other point that I failed to mention about an "optical cutter" is because the light spot is massless, the frequency response would inherently be uniform up to the resolution limit of the light spot! Likewise, using a Bell-Tainter air jet for reproduction could similarly provide a uniform response due to low mass.
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Postby ac7zl » Sun Jul 15, 2007 12:11 pm

I've tossed around the idea of building up a cylinder recorder/player... independent of my NBTV interests, just for the fun of it.

Aside from the mechanical issues, there is the question of blank media. Where can you get it?

My thought was to use black, ABS drainpipe. Cut it to length, chuck it in a lathe, turn the surface and edges true.

ABS is soft enough that a cold, chisel-shaped cutting needle could work it just fine. If not, it would be a simple matter to pass a current through the needle to heat it, to assist in cutting the plastic. ABS is tough enough that you could probably get many multiple plays with a blunt playback needle. I would modulate from side-to-side.

Nostalgia suggests selecting pipe sizes similar in diameter and length to the old Edison cylinders, but I'm thinking that 4" or even 6" diameter cylinders, perhaps even of extended length, would give you all the playing time you'd need.

Just an idea....

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Viewmaster wrote:Thanks for all the considered comments..much appreciated.

In 1877 Thomas Edison invented the phonograph using a cylinder of tin foil. But a short 6 years later in 1883 Paul Nipkow invented the scanning disc.

If these two men had ever met they may well have discussed bringing their ideas together to build a Edikow machine.
That is a bit of history that never was, and I am determined to build such a machine even if the picture is crappy.....as I know it will be.

I bet many NBTV owners would like to see what type of pictures would be possible from an Edikow...I certainly would.

Albert.
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Postby Steve Anderson » Sun Jul 15, 2007 4:36 pm

ac7zl wrote:I've tossed around the idea of building up a cylinder recorder/player... independent of my NBTV interests, just for the fun of it.
Nostalgia suggests selecting pipe sizes similar in diameter and length to the old Edison cylinders, but I'm thinking that 4" or even 6" diameter cylinders, perhaps even of extended length, would give you all the playing time you'd need.


I must admit that I've been eyeing up local drainpipes recently! But aside from that, it is as ever the recording process that's the hardest, playback is easy.

So does one use a brute-force method to carve a groove or something more subtle? It's almost a case of something soft and gooey when recording, then baked in a microwave for a while to achieve the required hardness and durability for many playbacks. I think my wifes' Yorkshire puddings would be suitable! (only for hand-to-hand combat).

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Postby Viewmaster » Sun Jul 15, 2007 6:31 pm

ac7zl wrote:I've tossed around the idea of building up a cylinder recorder/player... independent of my NBTV interests, just for the fun of it.

Aside from the mechanical issues, there is the question of blank media. Where can you get it?


You can get blank 2 minute discs for £7 each here in the UK.........
http://www.paulmorrismusic.ndo.co.uk/

Also in the USA for about the same price.........
http://www.78rpm.com/

.....you see, I have been doing my Edikow homework! :)

Yes drainpipe too but it may be too soft and not exactly round which the raindrops don't care about but NBTV would !!
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Best recording medium.

Postby Stephen » Mon Jul 16, 2007 12:13 am

Upon doing a bit of research on the internet, it seems that the solid material that most easily vaporises with applied heat is wax. In fact, a candle flame does not propagate from the melted wax or wick, but from the wax vapour itself.

Therefore, one ideal material for recording by means of an optical cutter that comprises a modulated LED array of some wavelength between infrared and ultraviolet focussed to a small spot might be the commercially available Edison wax cylinder recording blanks.

The recorder might include a means for blowing vapour away from the beam to minimise possible ignition. On the other hand, such means might just fan the flames.
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Postby Klaas Robers » Mon Jul 16, 2007 12:57 am

It is not so easy to focus the light of several LED's into ONE intensive light spot. Much easier is it to use a semiconductor laser as used in CD-R and/or DVD+RW recorders. Then you have already ONE spot, which is already very small and has an output power of about 150 mW of light.

Is that a usefull idea, or is it too unmechanical?
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Postby Stephen » Mon Jul 16, 2007 1:31 am

Klaas Robers wrote:It is not so easy to focus the light of several LED's into ONE intensive light spot. Much easier is it to use a semiconductor laser as used in CD-R and/or DVD+RW recorders. Then you have already ONE spot, which is already very small and has an output power of about 150 mW of light.

Is that a usefull idea, or is it too unmechanical?
That is an excellent idea, Klaas. The only issue would be the best way to modulate such a source in an analogue fashion. Is it possible to modulate the drive current for such a semiconductor laser to generate an analogue output?
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Postby Klaas Robers » Mon Jul 16, 2007 9:13 pm

Oh yes, in principle it behaves like an LED, so you can vary the current. But a better method is to drive it in duty cycle modulation. The speed is enormeous, so if you do that on 100 kHz it is much faster than the movement of the wax that you going to melt.

It look s more and mor to me that modern components are very usefull for old technologies. It is still a surprise that they could do with the old components.
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