Plotting patterns in music with a fantasy record player

http://www.windytan.com/2020/12/plotting-patterns-in-music-with-fantasy.html

by erikschoster • 6 years ago

152 18 6 years ago

windytan.com

jcims2• 6 years ago

Feast - http://www.windytan.com/p/posts.html

She's a beast.

th0ma52• 6 years ago

Picking out GPS coordinates from the recording of a news helicopter was astounding.

tasty_freeze• 6 years ago

I recall reading many years ago (20?) about a classical music afficianado with a unique ability that was really only useful at impressing other people at parties.

He could tell what record he was looking at by sight by inspecting the groove patterns: number of tracks, track length, and even the patterns of the active part of the song itself. As I recall, he was proud that he once identified the 1812 overture from more than 10 feet away because of the placement of the grooves at the loud parts.

BTW, records didn't necessarily have constant spacing -- the cutter knew the amplitude of the part of the spiral plus/minus one rotation away so it could place the track close as possible without causing collisions. I believe that made it easier to identify songs.

noyesno• 6 years ago

Maybe you are remembering Dr. Lintgen? https://www.snopes.com/fact-check/the-record-reader/

"Dr. Arthur Lintgen, a Philadelphia physician, can — within prescribed limits — determine which works of classical music are present on a phonograph record by “reading” the record’s grooves. His ability is not the result of any trickery — he performs the feat by combining a thorough knowledge of classical music with the technique of determining the structure and dynamics of a piece of music by examining the spacing and pattern of the grooves."

Vivtek• 6 years ago

Doug Hofstadter has written about that, I believe. It definitely sounds Hofstadterian, anyway.

the_cat_kittles• 6 years ago

god DAMN this is a fun post. i love it, and i have nothing to add other than thank you

0823498723498722• 6 years ago

I remember working at a place that had sun-diffusing window shades with a grid of small holes in them.

Walking from the elevators to my cubicle (I was only a summer intern, and hence had a cube, not an office) in the morning, I was greeted by an interesting interference pattern: there would be a counter grid of "dark spots", which unlike physical spots appeared large when one was far and got smaller as one approached...

th0ma52• 6 years ago

We have some shades similar to that I have used them to visualize the partial eclipse with coworkers.

pault• 6 years ago

I noticed during the last local eclipse that the light shining through the trees cast thousands of little eclipses on the ground. I thought it was way cooler than the eclipse itself.

jcims2• 6 years ago

Like this?

https://www.inverse.com/article/41595-hermann-grid-illusion-...

(Scroll down)

0823498723498722• 6 years ago

I think more of a Moiré...

skinkestek• 6 years ago

Ah. Finally!

Used to follow Oona on Google+, but forgot the name and haven't had a (working) RSS setup for the last few years so I hadn't read anything from her since then.

She's totally amazing when it comes to decoding signals, noticing effects and naming them (for example: there's a video on her YouTube channel with her filming a brick wall as she goes towards and back from a brick wall and she points out how the sound of a nearby waterfall changes.)

DanBC• 6 years ago

For people who are interested: https://www.youtube.com/watch?v=Amj4UevyRfU

dclowd9901• 6 years ago

Very cool, but the 3D illustration is off. Unless that record play speed is continuously variable, the aligned beats that come later in the animation should have a spiral-like pattern, otherwise the innermost rings would have a far faster rhythm.

Incidentally, a lot of sound engineers at the time would put tracks with less frequency dynamicism into those innermost rings to prevent records from skipping.

radiowave• 6 years ago

I don't follow you. The musical pattern repeats over a fixed length of time, and the turntable completes one rotation within the same length of time. How would that produce a faster rhythm in the innermost rings, absent a spiral?

zuminator• 6 years ago

otherwise the innermost rings would have a far faster rhythm.

Think that over. On a 33 1/3 LP, the outermost groove takes 1.8 seconds to complete a rotation. The innermost groove takes... 1.8 seconds to complete a rotation. Hence, over the entire record, every single groove lines encodes 1.8 seconds of information and lines up exactly with its neighbor in terms of time elapsed. The inner grooves have less space to cover but they compensate by moving more slowly. It's weird but makes sense in a way that's reminiscent of Aristotle's wheel paradox ( https://en.wikipedia.org/wiki/Aristotle%27s_wheel_paradox )

On a perfectly mastered LP, any song whose bpm is a multiple of 33 1/3 would have these lined up rhythmic patterns. E.g. a song that clocks in at 100 bpm would have exactly 3 beats in every rotation. You could make a faster dance song line up by speeding up the motor to a fractional degree.

Incidentally, a lot of sound engineers at the time would put tracks with less frequency dynamicism into those innermost rings to prevent records from skipping.

True, since the innermost grooves have less space to encode information, they have to wobble more in a given distance in order to maintain the same dynamic range. IIRC sometimes they would space those inner grooves further apart to give them more wobble room.

rland• 6 years ago

Neat, this reminds me of

https://www.math.uci.edu/~isik/posts/Eigentechno.html

(hn post https://news.ycombinator.com/item?id=24820824)

acomjean• 6 years ago

it reminds me of the "Woz a day" disc images, though not music related.

https://twitter.com/a2_4am/status/1022258525962219525

Plotting patterns in music with a fantasy record player

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