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ack

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NorthStar

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About 1,500 feet (one groove, one side only) - 18,000 inches (21 mins and few secs)
22 minutes; just over 1,550 feet (1,553.75)

* Let say 23 minutes per side (12" LP). I was giving it 20 minutes on average, from my sixties and seventies spinning. ...Total: some 38 others 42.
23 minutes equal 766.666666667 revolutions.
 
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PeterA

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NorthStar

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How do you go from 766.7 revolutions to 1500 feet?

1. If you click on the first line (wiki) of my above post it'll give you all the stats...1,500 feet.
2. 1 minute = 33 1/3 revolutions | Times 23 = 767 revolutions.

Are the two related?
_____

" The average LP has about 1,500 feet (460 m; 0.28 mi) of groove on each side. The average tangential needle speed relative to the disc surface is approximately 1 mile per hour (1.6 km/h; 0.45 m/s)."
 
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NorthStar

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1,500 feet is for one LP side of approximately 21 minutes and few seconds...one groove only.
21 minutes @ 33 1/3 rpm is 700 revolutions.
_____

L = Pi * N * (D + d)/2

D = outside diameter of the grooves (288 mm.)

d = inside diameter of the grooves (123 mm.) (D and d measured on a genuine K-Tel record.)

N = number of rotations: play-time times record speed of 33.33 rpm.
Assumed play time of 24 minutes times 33.33 rpm = 800 revs (rounded)


Putting the numbers in the formula and solving tells me the record presented a 516,478 mm. groove to the needle. 516,478 mm. is the same as:

516.5 meters, a little more than half a kilometer

1,695 feet, or 0.32 mile

And that's only for one side. If the other side is the same length the needle could then travel 1.033 km or 0.64 miles in 48 minutes. If all albums were this long (0.8 hours) you would be able to play 625 albums before you had 500 hours on your stylus. The needle would have traveled the equivalent of 400 miles through a vinyl canyon before you should be concerned with it's replacement. That is, if all LPs had 24 minute sides, AND, if the formula was right."
____

So:

- 20 minutes is less than 1,500 feet (1,412.5 feet / 666.666 revolutions)
* 21 minutes is roughly 1,500 feet (1,483.125 feet / 700 revolutions)
- 22 minutes is 1,553.75 feet (733.333 revolutions)
- 23 minutes is 1,624.375 feet (766.666 revolutions)
- 24 minutes is 1,695 feet (800 revolutions)

70.625 feet is the distance travelled by the stylus in one minute (33 1/3 revolutions).
 
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microstrip

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About 1,500 feet (one groove, one side only) - 18,000 inches.

* Let say 23 minutes per side (12" LP). I was giving it 20 minutes on average, from my sixties and seventies spinning. ...Total: some 38 others 42.
23 minutes equal 766.666666667 revolutions.

Just got 420 m using .6m x 35 x 20 - too lazy to get a calculator. :) Perfectly in agreement with your estimation ~ 17,000 inches.
 

NorthStar

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microstrip

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How many pits on average on one CD side?

Easy. 70 x 60x 40000 x 2 x 15 x 2 ~ 1E10 pits (my estimation, perhaps not the correct value! I will be very happy if it is more than half or less than the double or the real).
 

NorthStar

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Easy. 70 x 60x 40000 x 2 x 15 x 2 ~ 1E10 pits (my estimation, perhaps not the correct value! I will be very happy if it is more than half or less than the double or the real).

I mentioned one side but I meant one layer, unlike a Hybrid SACD.
Is the number 60 above for minutes?
 

microstrip

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I mentioned one side but I meant one layer, unlike a Hybrid SACD.
Is the number 60 above for minutes?

70 minutes 60 seconds 2 channels 15 bits 2 as pit ber bit ...
 

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