[Music]
I made a video a while back about
Chladni figures which are a way to
visualize the resonance of two
dimensional objects like this square
plate and ever since then I've been on
the lookout for other ways to visualize
sound through the vibrations that they
make or the vibrations that make them so
I was really happy to come across this
one thanks to Brian Mac and Wells he
showed me this demonstration and he's
allowed me to steal it for my channel so
here's the setup
I've got Bluetooth speaker which I've
put inside this bowl and then I've
stretched a giant balloon over the top
and then I've glued a fragment of mirror
to the surface this fragment of mirror
represents a sample of the kind of
movement that's going on on this rubber
membrane when you play music in the bowl
and we can interrogate that movement
with a laser the laser reflects off the
mirror and hits my wall so any movement
in the mirror will change the direction
of the reflected beam
so when we play music we see this kind
of messy chaotic pattern in the
reflected beam but if you play pure
notes you get some really interesting
effects this pure note generates a
pattern that we can understand quite
easily you might imagine the membrane of
the balloon kind of moving like this as
the note is played which makes sense so
the beam is going to be moving up and
down on the wall but maybe if it's got a
bit of this motion as well then you're
going to see a kind of oval shape what's
interesting is as we decrease the pitch
we see some changes
[Music]
the first thing to notice is as you
sweep the frequency down you get these
spikes in amplitude and I think what's
happening there is we're hitting the
resonating frequencies of the volume of
air inside the bowl as you get lower
still the patterns become a bit more
complicated like you get this figure of
8 and then you get this funny pattern
here what's really cool though is if you
start to layer different frequencies on
top of each other so this frequency
creates this pattern and this frequency
creates this pattern what about if we
combine the two
and then what if we add this third
frequency
so you can have loads of fun with this
create all sorts of mad shapes and
patterns by combining frequencies
together it's just a few of the patterns
I found by playing with two frequencies
on top of each other
[Music]
I wrote some JavaScript to help me sweep
through the frequencies with the kind of
precision that I needed if you're
interested in that code there's a link
in the description you'll be pleased to
know I've used very few comments this
was an interesting project to film
because I came up against some of the
differences between the way human eyes
work and the way cameras work so trying
to recreate the live experience was a
challenge like the way we see things is
continuous but the way a camera sees
things is frame by frame so I'm running
at 25 frames per second so every
twenty-fifth of a second you take a new
frame but you have a choice with each
frame for how long to keep the shutter
open for so you could keep the shutter
open just briefly and then it's closed
for the rest of that twenty fifth of a
second and you're opening it briefly
again and then close it open it briefly
then close it or you can keep it open
for the entire twenty fifth of a second
or something in between and you often
adjust that to fix motion blur or maybe
you want motion blur because that's part
of the human experience and you're
trying to recreate that but anyway if
you set your camera to manual then it's
going to make those calculations for you
to get the right amount of light to hit
the sensor but if you're filming
something like Laser bouncing off
vibrating mirror you better set your
camera to manual otherwise you're going
to have a bad time so for example
filming with a really fast shutter speed
you get this kind of pattern forming and
this is nothing like the true experience
of watching it live to get as close to
the live experience as possible
I set the shutter speed to be the full
twenty-fifth of a second but even then
there are differences and they're quite
enlightening actually take a look at
this
freeze-frame you can see the path that
the laser took whilst the shutter was
open and
you can actually see the start on the
end of the journey as well so this is
where the shutter opened the laser
travels for a bit and then this is where
the shutter closed though actually look
a bit closer and you can see it seems to
be more than one starting point or more
than one finishing point I don't really
know why I don't think it's because the
laser pulses otherwise I would have
noticed it watching it live in person it
may be to do with the way the frames are
stored and then reproduced anyway
interesting if you have some ideas let
me know
so while something like this looks quite
messy on camera because of all those
loose ends it still looks really nice in
person so having said that here are a
few more snippets that look really nice
in person and on camera
[Music]
so a big thank you to Brian Mack and
wells for putting me on to that project
also a big thank you to the sponsor for
this video it's an interesting one this
time because it's one that I use its
Skillshare so Skillshare how do you
describe it gosh it's like it's an
online community I suppose for creative
people where you can work through video
classes so we've got over 16,000
classes that you can learn about things
like so cameras for example if you're
interested in how cameras work and you
want to take that knowledge and you know
use it to make great videos and take
great pictures
there's loads of classes for you I used
the creative cinematography class which
really helped me out but whatever you're
interested in they've got lifestyle
stuff they've got technology stuff if
you're the sort of person who likes to
improve themselves then do yourself a
favor and check it out also use the link
in the description and the promo code
because then they know that I sent you
but also the first 300 people to use
that link will get two months of premium
membership free premium membership gives
you unlimited access to all those videos
there are so many resources so much like
source for inspiration if you want to
try something new and then after two
months it's as little as ten dollars a
month or if you don't like it then you
can quit and it won't cost you anything
so there you go check out Skillshare
that's it really I think I hope you
enjoyed the video if you did don't
forget to hit subscribe and click on the
notification bell as well because my
videos are a bit sporadic at the moment
that's the best way to make sure you
definitely hear about new videos alright
I'll see you next time
you