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My neighbor was telling me about these Tibetan Bells that he had seen
at someone's house. Basically it was an old gas cylinder that was cut in half
and hung so that it could be struck with a mallet and rung.
Step 1: Acquire an old gas cylinder
This sounded very cool and fun, and since I seem to have a bit of spare time these
days, I thought I would give it a try. I called around and found a welding supplier
that had plenty of condemed gas cylinders (bottles). We're talking about the big
oxygen type tanks that welders use. Anyway, the condemned bottles are basically
scrap metal and I was able to get some for free.
Step 2: Cut the bottom off of it
The guy at the welding supply place suggested an oxy-acetaline torch. They cut
off the tops of the bottles to ensure that they can't be used. I picked up a few of these
while I was there. It turns out that the torch does not offer a very straight cut.
On my way home, I stopped by my local neighborhood welding shop and tried to offer them a six pack
of beer to cut the the bottoms with a torch. After the young guy looked at me like I had six
heads and was a side dish he didn't order, he went in the back to get the old guy -- the dude who
has been welding for a hundred years.
This guy says, "So your gonna make bells, huh?" Cool.
He then says that "You never really know what was in these things, so it's not a good idea to use
a torch if you like keeping your body in it's natural uncharred state". He then mentions that he
has this really big bandsaw that would make short work out of my bells. This is cool I think.
He then mentions that unfortunately they are really busy and they can't get to it before
Wednesday (This was on a Friday). I mention the beer and told him that I would try it on my own
over the weekend and bring them back if I didn't get anywhere.
He never really bit on the beer references so I guess I'll have to drink 'em on my own.
Note: Oxygen tanks are made from steel and are pretty hard
Having gotten somewhat smarter from my recent woodworking projects, I decide to start on the
small one to see how it goes. I dig out the trusty sawzall (thanks dad) put on a metal blade,
and spray a little WD-40 on for lube, and dig in. Well actually, I drilled a hole in it first
but the blade was bigger than the hole, so I had to cut on the outside of the cylinder for a while
with the sawzall until I got to the point that I could get the blade inside. Once I got the blade
in it went fairly quickly and I was able to cut the bottom off in about 20 minutes.
Note: Don't try to cut a straight line around a cylinder by eye. Make a line to follow instead
Between my drill hole and my wild cutting, I had a pretty ragged edge. It turns out that the smoother the
edge, the better. Needless to say it didn't sound bad but not great either.
Note: The science of the acoustics of bells is pretty serious stuff
It turns out that a search for "bells homemade acoustics" returns quite
a few hits in the major search engines.
After some searching over a couple of days, I finally found some decent links:
I also found this cool program
at the Church Bell site that will do a sound analysis of a bell and point out all the frequencies.
To make a very long and very complicated
explaination of a-bunch-of-stuff-I-don't-quite-understand-yet short and to the point,
bells do not have one frequency (tone). They have a strike tone, a hum tone, and a
bunch of other tones in between as well as overtones of the aforementioned tones.
This makes it very difficult to measure the musical
note of a bell since it has such a complex sound. Suffice it to say, I have analyzed
my bells with the program but I don't know what to make of the results ;->.
Note: Being a geek who likes to collect electronic sound related stuff can come in handy
It turns out that I can plug my digital multimeter that can read frequency into my
SPL meter (tells you how loud something is) and I can see the frequency that my
bells are ringing at. I also can hook up my tone generator, and play tones until
I get one that sounds like my bell. Then I can look at the tone generator and see
what frequency the bell is although this is pretty subjective.
Note: Bells are very complex and do not have one tone
Since bells don't really have one tone, having this homebrew measuring
equipment doesn't really get me very far. Did I mention that the idea
is to make a large bell xylophone with 4 or 5 bells to hang at the end
of the driveway for the neighborhood kids to play with? Gotta love
interactive "art". So I need to figure out what length bell will give
me what tone.
Note: Even Einstein had to start somewhere
Since the bell theory that I have been able to find focuses on conventional
bells and mine aren't (not that I really understand it anyway ;->),
and since I have yet to find anybody who has done
this before, I'm on my own. Unfortunately, it takes about 45 minutes to
cut a section off of a large cylinder, so exprimentation takes time and
effort (and plenty of saw blades).
I've decided to record the tones from each bell as well as the
general dimensions and post them here so that hopefully, other
folks can take advantage of some my sweat and callouses.
Note: On the internet everyone can hear you scream
During my lovely traversal through the search engines, I ended up sending
email to 3 or 4 folks involved with various websites that I came across
asking for help, guidance, wisdom, or a point in the right direction.
The only person who was kind enough to take pity on me was the wonderful
Bart Hopkin at Experimental Musical Instruments.
Besides emailing me with a good primer and some good direction he also
pointed me to oddmusic.com which also has an
associated yahoo group.
By the way, make sure to check out the photo
gallery at oddmusic. There is some cool stuff in there!
The very nice folks on the oddmusic yahoo group pointed me to another
good yahoo group: tuning -
the Alternate Tunings Mailing List. These folks are way smart and
really know about musical theory. They too took pity on me and have started
to offer me some really helpful info as well.
Note: As easy as these are to make, very few folks seem to make them
Everybody that I mention this idea too seems to think it cool, and
everybody who hears the bells ring is pretty impressed that something
so mundane and ugly can sound... well, nice. Since cutting the
bottoms off of these tanks until you get a sound that you like is not
at all difficult, I'm really surprized that you don't see more (if any)
of these things.
|Page last updated 28-July-2001
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