Hi, I want to find out why wire recorders worked at that high wire speed?
Wikipedia states "Compared to tape recorders, wire recording devices have a high media speed, made necessary because of the use of the solid metal medium. Standard postwar wire recorders use a nominal speed of 24 inches per second (610 mm/s), making a typical one-hour spool of wire 7,200 feet (approx. 2200 m) long."
Why does the solid metal medium require greater speed?
What if I lower down the speed, what will happen?
Wikipedia states "Compared to tape recorders, wire recording devices have a high media speed, made necessary because of the use of the solid metal medium. Standard postwar wire recorders use a nominal speed of 24 inches per second (610 mm/s), making a typical one-hour spool of wire 7,200 feet (approx. 2200 m) long."
Why does the solid metal medium require greater speed?
What if I lower down the speed, what will happen?
I don't exactly know why. But my guess it because the wire is stainless steel. Its a good magnetic material due to high iron content. If its recorded at low speed, the recorder head could affected the magnetic field of post recorded signals. This is analogue so field strength is just as important.
Solid iron shorts-out the magnetic fiels of the higher frequencies. Making high freqs "long" by using a high speed makes this loss tolerable.
"Tape" is usually understood to be iron (oxide) *particles*. Since they don't quite touch each other, high (small) frequency loss is less.
Also wire is cheap and compact. (Mass produced industrial product not much thicker and much narrower than tape.) Using a lot of it was not a big cost. Conceptually the high-freq response of "wire" could be improved by sintering teeny particles of iron(oxide) into (or onto) a "wire". That would be expensive and fragile, or need massive development of ceramic(?) binder to make it robust (but expensive).
Lower speed does the same as in tape: reduced high frequency response and output. Nothing "bad" happens, it just gets too dull to be called "good sound". (And the best wire recorders were not all that great anyway.)
Tape improved so much that for decades all long-time logging work was on tape. As slow as 1ips, but large reels, many tracks, auto-reverse. Could log days of airplane or police radio traffic. This is now vanishing because my $39 cellphone with a $10 card can record 56 hours of speech, and any kind of hard-drive or large flash storage can hold centuries of sound.
"Tape" is usually understood to be iron (oxide) *particles*. Since they don't quite touch each other, high (small) frequency loss is less.
Also wire is cheap and compact. (Mass produced industrial product not much thicker and much narrower than tape.) Using a lot of it was not a big cost. Conceptually the high-freq response of "wire" could be improved by sintering teeny particles of iron(oxide) into (or onto) a "wire". That would be expensive and fragile, or need massive development of ceramic(?) binder to make it robust (but expensive).
Lower speed does the same as in tape: reduced high frequency response and output. Nothing "bad" happens, it just gets too dull to be called "good sound". (And the best wire recorders were not all that great anyway.)
Tape improved so much that for decades all long-time logging work was on tape. As slow as 1ips, but large reels, many tracks, auto-reverse. Could log days of airplane or police radio traffic. This is now vanishing because my $39 cellphone with a $10 card can record 56 hours of speech, and any kind of hard-drive or large flash storage can hold centuries of sound.
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Many years ago, a company called Ditchburn made a voice recorder using an aluminium platter with a steel band around the outside next to stationary heads.
VOX made a copy machine based on multiple playback/record heads with a similar record player style platter. This quickly moved onto tape with ferros material that has a better frequency responce at higher frequencies, allowing for slower speeds for similar response times.
Research is still ongoing with high speed media using polarized electrons and a piece of wire. Seagate have spent a lot of time perfecting the transmit and receive "heads".
The only restriction is the speed of electron flow and of course the Earth's gravity and magnetic interference.
Won't be long though.
VOX made a copy machine based on multiple playback/record heads with a similar record player style platter. This quickly moved onto tape with ferros material that has a better frequency responce at higher frequencies, allowing for slower speeds for similar response times.
Research is still ongoing with high speed media using polarized electrons and a piece of wire. Seagate have spent a lot of time perfecting the transmit and receive "heads".
The only restriction is the speed of electron flow and of course the Earth's gravity and magnetic interference.
Won't be long though.
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Hello,
Unless it is 430 stainless steel stainless steel will be not magnetic.
Greetings, Eduard
Well if the high frequency response is the reason for the high speed, why couldn't we use an emphasis of the highs during recording so that the audio response curve is equalized, without the need for high speed? Dolby on tapes does a very similar thing, but back on the wire days there was no dolby probably.
So suppose I experiment with a tape head that writes on a wire, this could improve the high frequency response due to the narrower gap, without the need for high speed?
Oh no, I do not own one. I design one!
Here is a preliminary rough design of mine. It does not show the parts details so do not build it until I finish it and present it here. It is my idea and improvements over the original designs of wire recorders. Of course some things from the tape recorders have been borrowed and applied to the wire, like the capstan/spindle pair, to achieve constant speed.
The spools are not compatible with the vintage wire recorders, because my design aims on mechanical simplicity. Keeping the spools large in diameter, but with very little width for the wire to be wound, avoids the use of a complex "fishing reel" winding mechanism. Because of the spindle/capstan there is no speed change caused by the large diameter of spools. I use 0.4mm wire which is a bit thicker than the originals, but it is stronger and less prone to breaking. The large diameter spools would in theory hold quite a good amount of wire.
Fast forward function is provided and stretching of the wire is performed by reverse movement (but low torque) of the reels motors.
So you see how simple my design is?
Any comments are more than welcome!
So In that design I would like to investigate the effects of speed reduction combined with preemphasis of the high frequencies. Basically the previous questions in the previous posts (#8 and #9), just to find out more about the speed issues.
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Look at a different form of writing. Liquid ink.
Ink on a tight-weave non-absorbent paper can write very small marks.
Ink on blotting paper, or paper towel, all marks spread-out, you can't write small.
Solid-metal "conducts" the magnetism, "spreads" it.
Rust media, the particles don't touch, small magnetic writing does not "blot" and spread so much.
You can't apply "infinite" EQ. The recording systems we know and use already have great heaps of many-pole high-boost. Any more gets trouble with record distortion or play hiss. This would be comparable to a smaller pen and sharper magnifying glass on the ink: at some point you just can't make/read any smaller.
Some, even much, "Stainless Steel" is mildly magnetic. The term covers MANY alloys. Some are actually "heat resisting" steel for boilers and turbines. There's SS which will stay bright in salt-air for decades, and SS which won't show much rust in soup-spoon use (short exposure to mild acid and occasional washing).
Yes, recording wire was "stainless". IIRC, it didn't rust like fence-wire, but with long damp storage it got lightly crusty. Here's a contemporary survey:
https://www.americanradiohistory.com/Archive-Audio/50s/Audio-1953-Dec.pdf
15MB PDF, page 19 et seq
Recording wire is said to be 18/8 stainless steel, which apparently is a "cutlery grade" (so, soup-spoons).
Stainless steel - Wikipedia
"Ferritic and martensitic stainless steels are magnetic.
"Annealed austenitic stainless steels are non-magnetic. Work hardening can make cold-formed austenitic stainless steels slightly magnetic."
Ink on a tight-weave non-absorbent paper can write very small marks.
Ink on blotting paper, or paper towel, all marks spread-out, you can't write small.
Solid-metal "conducts" the magnetism, "spreads" it.
Rust media, the particles don't touch, small magnetic writing does not "blot" and spread so much.
You can't apply "infinite" EQ. The recording systems we know and use already have great heaps of many-pole high-boost. Any more gets trouble with record distortion or play hiss. This would be comparable to a smaller pen and sharper magnifying glass on the ink: at some point you just can't make/read any smaller.
Some, even much, "Stainless Steel" is mildly magnetic. The term covers MANY alloys. Some are actually "heat resisting" steel for boilers and turbines. There's SS which will stay bright in salt-air for decades, and SS which won't show much rust in soup-spoon use (short exposure to mild acid and occasional washing).
Yes, recording wire was "stainless". IIRC, it didn't rust like fence-wire, but with long damp storage it got lightly crusty. Here's a contemporary survey:
https://www.americanradiohistory.com/Archive-Audio/50s/Audio-1953-Dec.pdf
15MB PDF, page 19 et seq
Recording wire is said to be 18/8 stainless steel, which apparently is a "cutlery grade" (so, soup-spoons).
Stainless steel - Wikipedia
"Ferritic and martensitic stainless steels are magnetic.
"Annealed austenitic stainless steels are non-magnetic. Work hardening can make cold-formed austenitic stainless steels slightly magnetic."
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When recorded wavelength becomes comparable to recording "window" width it starts erasing itself.
EQ cannot help you with what´s not there to begin with.
Same way as no amount of EQ will turn a 1" "woofer" into a PA type one.
Historical papers:
AUDIO - Consumer audio and music magazine from 1947 to 2000.
Nov '47, Dec '47, Jan '48
ELECTRONICS: Electronics Engineering magazine beginning in 1930
Jul '45
AUDIO - Consumer audio and music magazine from 1947 to 2000.
Nov '47, Dec '47, Jan '48
ELECTRONICS: Electronics Engineering magazine beginning in 1930
Jul '45
Hi again,
The head used to be a toroid with a gap at one end and onto the toroid the wire was wound. The toroid then becomes an electromagnet with changing magnetic field intensity, depended on the signal fed into it.
A problem with the wire recorders is referenced on wikipedia:
"Poulsen's original telegraphone and other very early recorders placed the two poles of the record/replay head on opposite sides of the wire. The wire is thus magnetised transversely to the direction of travel. This method of magnetization was quickly found to have the limitation that as the wire twisted during playback, there were times when the magnetization of the wire was at right angles to the position of the two poles of the head and the output from the head fell to almost zero. The development was to place the two poles on the same side of the wire so that the wire was magnetised along its length or longitudinally. Additionally, the poles were shaped into a "V" so that the head wrapped around the wire to some extent. This increased the magnetising effect and also increased the sensitivity of the head on replay because it collected more of the magnetic flux from the wire. This system was not entirely immune to twisting but the effects were far less marked. The longitudinal method survives into magnetic tape recording to this day. "
So now I wonder, if I can wrap a solenoid around a plastic former and pass the wire through the coil. The solenoid should magnetize the wire with the longitudinal method, as the wire itself will become the "core" of the electromagnet. And this should eliminate the twisting problem mentioned above, as the wire would be magnetized all the way around.
I have seen this technique applied in a thin rope covered with magnetic particles, Wire Recorders - Museum of Magnetic Sound Recording see this http://museumofmagneticsoundrecording.org/images/R2R/HistoryOberlinSmith2.jpg
Will this work?
> wrap a solenoid around a plastic former and pass the wire through the coil
Sounds like the equivalent of a very long "gap". Mildly wasteful for record. Very-very limiting of highs on playback. Encourages high wire speeds, and I thought you wanted lower speed?
But if you have a working transport, it is a cheap experiment.
Sounds like the equivalent of a very long "gap". Mildly wasteful for record. Very-very limiting of highs on playback. Encourages high wire speeds, and I thought you wanted lower speed?
But if you have a working transport, it is a cheap experiment.
Because the medium is huge, hundreds of microns across, limiting the bandwidth. Magnetic tape active layer can be a few microns, hard disk media much thinner still.
Its pure geometry, different parts of the signal must not overlap in space. hard drive technology has taken the art to extremes, using sophisticated multi-layer materials and vertical magnetic flux focussing using a backing layer. This is how you get 10^12 bits per square inch or whatever the record is now.
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