aeh5040

Pendulum wave music machine

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This is absolutely beautiful, reminds me of piano phases experiments by Steve Reich. The previous "visual" version was hypnotic, but this is entirely something else. I would sell my left kidney for an instruction.

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Love it!

What are the gear ratio's? A assume they are the same between each consecutive pair?

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Posted (edited)
1 hour ago, m00se said:

What are the gear ratio's? A assume they are the same between each consecutive pair?

I think the differentials are the key here- you see a lot of them, in red. 

What they do here, is that they take the left input, and then the right input, and take the average of that. 

If you would build a system like this with three hammers, it's simple: the left hammer runs on the left input, which is a bit slow. The right hammer runs on the right input, which is just a bit faster than the left input. The middle hammer runs off the differential, and thus has a speed which is exactly the average of the two inputs. 

Fun thing is; you can stack differentials. So if you want to run the system with five hammers, you already have the speeds of the far left and far right hammers (which are the slow and fast inputs), and you have the middle hammer, which is the average of the two. If you want to figure out the speeds of hammers 2 and 4, you use another differential, which takes the average of the left input and the middle, or the right input and the middle. 

This system has 9 hammers, so, that's the previously described mechanism taken one step further. (Well, it has 8 hammers- for reasons unknown to me the leftmost hammer was removed...)

 

I hope this all made sense, and that I got the explanation right. 

 

aeh5040: It's a great model, and I love the solution you came up with to keep everything running in time. 

Edited by mahjqa

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12 hours ago, mahjqa said:

I hope this all made sense, and that I got the explanation right. 

Makes sense. Thanks for the clear explanation.

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It is amazing. I liked the previous visual version but this acoustic is even more interesting.

It seems to me that the stacked differentials is a hot topic of this season. A couple of weeks ago we had here another fascinating MOC a 64-Speed Lego Technic Gearbox, also based on differentials.

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Thank you for the kind remarks, folks!

18 hours ago, domleg said:

This is absolutely beautiful, reminds me of piano phases experiments by Steve Reich. The previous "visual" version was hypnotic, but this is entirely something else. I would sell my left kidney for an instruction.

OK, I guess I have to produce instructions (no kidneys necessary).  In the meantime, it is very similar to the synchropods, for which I already made instructions https://rebrickable.com/mocs/MOC-8109/aeh5040/synchro-pods/. And maybe I'll post some pictures...

18 hours ago, m00se said:

Love it!

What are the gear ratio's? A assume they are the same between each consecutive pair?

That's right.  The ratios are 72:73:74:75:76:77:78:79:80.

16 hours ago, mahjqa said:

...

This system has 9 hammers, so, that's the previously described mechanism taken one step further. (Well, it has 8 hammers- for reasons unknown to me the leftmost hammer was removed...)

I hope this all made sense, and that I got the explanation right.

Yep, pretty much a perfect explanation.  No particularly strong reason for only using 8 hammers.  I just thought an octave and an 8-beat rhythm might sound better musically.

One very important detail is the use of the white clutch gears, which enable fine adjustment of the timing.  I was concerned that they might slip over time, but there's no evidence of that at the moment.  The hammers don't need much torque. 

I also made lot of use of the little technic rubber thingies - to make the hammers flexible, to dmap their fall, and to isolate the whole thing from the floor to cut down on vibration noise.

45590.png

 

1 hour ago, Jonas said:

It is amazing. I liked the previous visual version but this acoustic is even more interesting.

It seems to me that the stacked differentials is a hot topic of this season. A couple of weeks ago we had here another fascinating MOC a 64-Speed Lego Technic Gearbox, also based on differentials.

Differentials rock!

I was also inspired a lot by the videos on this channel I may try for a 2-octave verison if I can find a way to fit it around the xylophone...

 

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Love your models! This one particularly, I happened to have my bass out watching YouTube vids so I played along:) Some interesting polyrhythms happened!

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