Chladni testing...first steps

[kiwigeo]

Okay my Bradley tone generator arrived the other day and yesterday a 50watt speaker arrived so its time to have a play around with chladni patterns.

Did a test run on a classical last night but wasn't happy with the Earl Grey tea leaves I was using so decided to try poppy seeds. I bought a few packets of poppy seeds (10 actually) and as I was going through the supermarket check out I got some strange looks from the staff......most of them thinking what the hell a guy my age was doing smoking poppy seeds.

Will be playing around with the set up over the next week or two and will post up some pics once Ive got some worthwhile results. I also have to have a talk to the neighbour and let them know that the weird noises from my workshop are not captive aliens...they're German Shepard goes off when I hit 100Hz with the tone generator.....it's obviously the mutt's resonant frequency.

[Bruce McC]

".....I got some strange looks from the staff......"

Perhaps it was the mo :

[kiwigeo]

Yeah might have been the mou'....

[woodrat]

.....it's obviously the mutt's resonant frequency.

[Cookie man]

What about sand? or coffee sediment? would they work well for chladni patterns?

haha, smoking poppy seeds

[graham mcdonald]

Martin,

Glitter works well (little flecks of coloured aluminium foil) or even sawdust from the bandsaw. Expect to blow up your speaker quite regularly. I ran some soundboards through Chladni pattern testing in an anechoic chamber at the university a few years back when working on the first book, with Neville Fletcher showing me what to do. The speaker blew up within half an hour, and he said that was normal because of the SPL you need to excite the soundboard.

cheers

graham

[charangohabsburg]

What about a German Shepard as electricity free guitar amplifier? Sounds bad.
Be happy that you neighbour does not own a tiger, puma or a huge snake...

Glad your "setup" works though.

What about sand?

Too heavy.

or coffee sediment?

Too greasy, I guess (and maybe too heavy too).

[kiwigeo]

What about sand? or coffee sediment? would they work well for chladni patterns?

haha, smoking poppy seeds

Sand very dense and abrasive of you accidentally rub it on a finish. Coffee sediment...might work when dry but it tends top absorb moisture and get claggy. My wife puts it into pantihose bags and hangs them in her wardrobe to absorb odours....during the winter the stuff gets damp.

The tea leaves work but the poppy seed is better for showing up more subtle antinodes/nodes.

Glitter.....I believe it works a treat but Trevor Gore mentions it being a pain to get out of the instrument.

At some stage Im going to give the lute a chladni session....just have to work out how to stop the poppy seeds getting through the rose. Should be an interesting exercise.

[TKAY]

How would it be to put cling wrap over the timber first?

[kiwigeo]

How would it be to put cling wrap over the timber first?

Cling wrap not good on some finishes.

Forget sand....poppy seed is the go. If you get sick of playing with CHladni patterns then you can fill a pipe with the seeds and create a few Chladni patterns inside your head.

[peter.coombe]

I use Jarrah sawdust. It works and is easy to see against Spruce. Tried glitter, it works very well but is horrible stuff to remove, sticks to everything.

[pat foster]

Hi, folks. Haven't posted in a while, but I thought I might contribute something here.

The problem with getting rid of glitter is that most of what's available is chopped up mylar or something similar, and it holds a static charge. If you can find the old metallic stuff, aluminum I think, it's a lot more manageable. Harder to find though.


Pat