Naked Science Forum
Non Life Sciences => Technology => Topic started by: Karen W. on 26/02/2009 08:37:38
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Well I know this is old technology but I am curious as to the procedures in making a vinyle recorded record. ((music)
What exactly goes into the medium that makes the record and also the technology involved in making the vocal print in the record itself..?
It all seems like a bit of magic to me!
Can someone tell me how this is done.... at my level please..... [;D] [:)]
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As to how they transcribe a waveform onto the disk, I'm not entirely sure - but one interesting thing is that the 'rate' of the music changes as you get closer to the centre of the disk - this is because the disk is turned at constant speed, so as you get closer to the centre, it takes less time to do one full rotation. There's a good demonstration of it here: http://www.thenakedscientists.com/HTML/content/interviews/interview/815/
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As far as I know, sound waves picked up by a microphone are translated into vibrations which are etched into the sides of the groove on a master disc.
Take a look at this Karen, it explains how the vinyl disc is pressed.
Part 1
http://www.youtube.com/watch?v=xUGRRUecBik (http://www.youtube.com/watch?v=xUGRRUecBik)
Part 2
http://www.youtube.com/watch?v=IReDh9ec_rk&feature=related (http://www.youtube.com/watch?v=IReDh9ec_rk&feature=related)
There's quite some explanation on the actual recording methods here http://en.wikipedia.org/wiki/Gramophone_record (http://en.wikipedia.org/wiki/Gramophone_record)
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As to how they transcribe a waveform onto the disk, I'm not entirely sure - but one interesting thing is that the 'rate' of the music changes as you get closer to the centre of the disk - this is because the disk is turned at constant speed, so as you get closer to the centre, it takes less time to do one full rotation. There's a good demonstration of it here: http://www.thenakedscientists.com/HTML/content/interviews/interview/815/
Thanks Ben..Lots of good information in there.
You know The part you wrote about the fact that the rings getting smaller as it reaches the center makes it harder to understand..I get the difference in the speed of rotation being quicker because the size changes but I stiil am confused about how they make up for that....I will read it again...maybe I am missing something there.
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As far as I know, sound waves picked up by a microphone are translated into vibrations which are etched into the sides of the groove on a master disc.
Take a look at this Karen, it explains how the vinyl disc is pressed.
Part 1
http://www.youtube.com/watch?v=xUGRRUecBik (http://www.youtube.com/watch?v=xUGRRUecBik)
Part 2
http://www.youtube.com/watch?v=IReDh9ec_rk&feature=related (http://www.youtube.com/watch?v=IReDh9ec_rk&feature=related)
There's quite some explanation on the actual recording methods here http://en.wikipedia.org/wiki/Gramophone_record (http://en.wikipedia.org/wiki/Gramophone_record)
Thanks Don.. very cool..I will watch them.. that sounds facinating.. do you tink there is a way one could make a home made primative version that would work........to demo for kids how the voice is placed on..the record...?
I will watch the utube links tomorow..thank you so much!
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As far as I know, sound waves picked up by a microphone are translated into vibrations which are etched into the sides of the groove on a master disc.
I thought I'd just add that the vibrations aren't etched in to the sides of the groove on the master; the groove, incorporating the signal is cut in to a blank master on a lathe. The cutting head generally has two very powerful solenoids, angled to match the two sides of the groove, so that when the left and right signals are fed to them they cut the signals in to the appropriate side of the groove (in stereo disks).
The pitch of the grooves (although it's really just a single groove,of course), that is, how widely spaced they are, depends upon the maximum amplitude of the signal being cut; a signal with a very high amplitude results in greater movement of the cutting head, which in turn means that the grooves must be further apart to ensure that each groove doesn't interfere with the grooves either side of it.
There's a few pictures of a mastering lathe on this site, including some close-ups of the cutting head showing the angled coils (they seem to have screwed up the picture aspect ratio on some of the pics though)
http://www.soundsolutionmastering.com/index5.htm (http://www.soundsolutionmastering.com/index5.htm)
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Umm, yes, that's what I meant LeeE. My choice of words left something to be desired.
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As to how they transcribe a waveform onto the disk, I'm not entirely sure - but one interesting thing is that the 'rate' of the music changes as you get closer to the centre of the disk - this is because the disk is turned at constant speed, so as you get closer to the centre, it takes less time to do one full rotation. There's a good demonstration of it here: http://www.thenakedscientists.com/HTML/content/interviews/interview/815/
Thanks Ben..Lots of good information in there.
You know The part you wrote about the fact that the rings getting smaller as it reaches the center makes it harder to understand..I get the difference in the speed of rotation being quicker because the size changes but I stiil am confused about how they make up for that....I will read it again...maybe I am missing something there.
You are confused because it doesn't make sense.
An LP record turns at 33 revolutions per minute and, whether the needle is near the edger or near the center, each turn takes the same time (1/33 min ie about 2 seconds).
What changes is the speed of the needle with respect to the record (which falls as the record plays).
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As to how they transcribe a waveform onto the disk, I'm not entirely sure - but one interesting thing is that the 'rate' of the music changes as you get closer to the centre of the disk - this is because the disk is turned at constant speed, so as you get closer to the centre, it takes less time to do one full rotation. There's a good demonstration of it here: http://www.thenakedscientists.com/HTML/content/interviews/interview/815/
Thanks Ben..Lots of good information in there.
You know The part you wrote about the fact that the rings getting smaller as it reaches the center makes it harder to understand..I get the difference in the speed of rotation being quicker because the size changes but I stiil am confused about how they make up for that....I will read it again...maybe I am missing something there.
You are confused because it doesn't make sense.
An LP record turns at 33 revolutions per minute and, whether the needle is near the edger or near the center, each turn takes the same time (1/33 min ie about 2 seconds).
What changes is the speed of the needle with respect to the record (which falls as the record plays).
Yes, sorry, I didn't really explain myself very well there.
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The metal (aluminium, I think) master disc is /was cut with a Lathe - a pair of strong electromagnets, mounted at 45degrees to the vertical, which move the cutting tool according to the left and right channels. This leaves a wavy groove which also varies in depth. The side to side movement carries the mono information and the vertical movement carries the stereo signal.
The disc goes round at a steady 33 1/3 rpm. This means that the system wastes some capacity. The inner turn of the groove needs to be cut at a suitable speed for reproduction and the outer turn is probably going about twice as fast as necessary.
Some early (78 rpm) disc systems had a variable speed (rpm) so that the cutting speed of the groove (m/s) was constant. This gave a bit more capacity. It was too fiddly, however, and required a more complex gramophone mechanism.
Interestingly, the 'early' 3 1/2 inch floppy disc drives (PC) used a constant speed but the Macintosh system varied the disc rotation speed and obtained a bit more capacity.
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See CAV vs CLV
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As far as I know, sound waves picked up by a microphone are translated into vibrations which are etched into the sides of the groove on a master disc.
Take a look at this Karen, it explains how the vinyl disc is pressed.
Part 1
http://www.youtube.com/watch?v=xUGRRUecBik (http://www.youtube.com/watch?v=xUGRRUecBik)
Part 2
http://www.youtube.com/watch?v=IReDh9ec_rk&feature=related (http://www.youtube.com/watch?v=IReDh9ec_rk&feature=related)
There's quite some explanation on the actual recording methods here http://en.wikipedia.org/wiki/Gramophone_record (http://en.wikipedia.org/wiki/Gramophone_record)
Don I just finished watching both of the Utube links ! So Cool! I* had no idea what went into making those records.. amazing.. I want to hang on to those Utube links.. great demonstration very cool! Thank you so much!
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As to how they transcribe a waveform onto the disk, I'm not entirely sure - but one interesting thing is that the 'rate' of the music changes as you get closer to the centre of the disk - this is because the disk is turned at constant speed, so as you get closer to the centre, it takes less time to do one full rotation. There's a good demonstration of it here: http://www.thenakedscientists.com/HTML/content/interviews/interview/815/
Thanks Ben..Lots of good information in there.
You know The part you wrote about the fact that the rings getting smaller as it reaches the center makes it harder to understand..I get the difference in the speed of rotation being quicker because the size changes but I stiil am confused about how they make up for that....I will read it again...maybe I am missing something there.
You are confused because it doesn't make sense.
An LP record turns at 33 revolutions per minute and, whether the needle is near the edger or near the center, each turn takes the same time (1/33 min ie about 2 seconds).
What changes is the speed of the needle with respect to the record (which falls as the record plays).
Ok..I think I get that better...
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As to how they transcribe a waveform onto the disk, I'm not entirely sure - but one interesting thing is that the 'rate' of the music changes as you get closer to the centre of the disk - this is because the disk is turned at constant speed, so as you get closer to the centre, it takes less time to do one full rotation. There's a good demonstration of it here: http://www.thenakedscientists.com/HTML/content/interviews/interview/815/
Thanks Ben..Lots of good information in there.
You know The part you wrote about the fact that the rings getting smaller as it reaches the center makes it harder to understand..I get the difference in the speed of rotation being quicker because the size changes but I stiil am confused about how they make up for that....I will read it again...maybe I am missing something there.
You are confused because it doesn't make sense.
An LP record turns at 33 revolutions per minute and, whether the needle is near the edger or near the center, each turn takes the same time (1/33 min ie about 2 seconds).
What changes is the speed of the needle with respect to the record (which falls as the record plays).
Yes, sorry, I didn't really explain myself very well there.
That's ok.. It takes me a bit and rereading sometimes many times before I get something... Thanks Ben!