Discussion:
Tongue/Slit Drums -- any tips for tuning?
(too old to reply)
Mike
2004-01-07 00:15:00 UTC
Permalink
Hello,

I am endeavouring to make a tongue drum or two (or three or six...)
and I was wondering if anyone here has had any experience with making
them. I have read about the basic construction which is simple
enough, however I have yet to come across anything that deals with
tuning (to any great degree). So I have a few questions:

1. Is the pitch influenced mainly by tongue length, or is width a
factor as well?

2. I understand that shortening a tongue will raise the pitch, and
hollowing out the tongue will lower the pitch -- but are there any
basic guidlines (tongue area calculations) for attaining any specific
pitches? Or at least getting as close as possible before having to
"fine tune" the tongue (which I assume is inevitable)??

3. Any suggestions as far as which wood to use? What are the virtues
of cherry vs maple etc...?

Many, many thanks in advance to anyone who can help, or point me in
the directin to find more help.
b***@iwaynet.net
2004-01-07 03:09:52 UTC
Permalink
Post by Mike
Hello,
1. Is the pitch influenced mainly by tongue length, or is width a
factor as well?
2. I understand that shortening a tongue will raise the pitch, and
hollowing out the tongue will lower the pitch -- but are there any
basic guidlines (tongue area calculations) for attaining any specific
pitches? Or at least getting as close as possible before having to
"fine tune" the tongue (which I assume is inevitable)??
I'm not sure I've ever seen any equations for "tongue drums"
but I can give a hint or two. Basically, you have a mass
(the tongue) which is connected to a spring (the connection to the
box). The two together make a vibrating system.

The mass, however is distributed along the tongue so it's not so
trivial to calculate a frequency. You'd first have to find the
equivalent mass and the distance of that "equivalent" mass from
the spriny support. Then you'd have to figure out the spring
constant of the bending point. Again this is more or less distributed
also so again you'd have to calculate some kind of "equivalent"
spring. I doubt that this is at all easy to do.

But knowing this gives you some hints. A longer tongue is lower in
pitch. If you add more mass on the end (thicker or wider there)
It makes it go lower. If you make it less springy where it joins
the box top (hollow out not only the tongue but BOTH the top and
tongue where it joins to make the flexing point weaker) LOWERS
pitch. Making the end of the tongue narrower only on the end raises
the pitch. But note that just making the WHOLE tongue wider
may not do much as you add mass on the end, but the wider
connection to the box is stiffer. Hence the mass is lowering
the pitch while the spring part is raising it!

My guess is that you are just going to have to get some boards
of the wood you plan to use and cut some tongues and give them
a try. The kind of wood changes the springyness and the tongue
mass so THAT also makes a difference.

Finally you want to tune the box to reinforce the tones of the
tongues (sort of like a guitar). Generally you have a closed
box except for a hole somewhere and that is a Helmholtz resonator.
You CAN find formulas for that.

Good Luck!

Benj
--
Due to SPAM innundation above address is turned off!
O-Lugs
2004-01-07 07:27:08 UTC
Permalink
Post by Mike
Hello,
I am endeavouring to make a tongue drum or two (or three or six...)
and I was wondering if anyone here has had any experience with making
them. I have read about the basic construction which is simple
enough, however I have yet to come across anything that deals with
1. Is the pitch influenced mainly by tongue length, or is width a
factor as well?
2. I understand that shortening a tongue will raise the pitch, and
hollowing out the tongue will lower the pitch -- but are there any
basic guidlines (tongue area calculations) for attaining any specific
pitches? Or at least getting as close as possible before having to
"fine tune" the tongue (which I assume is inevitable)??
3. Any suggestions as far as which wood to use? What are the virtues
of cherry vs maple etc...?
Many, many thanks in advance to anyone who can help, or point me in
the directin to find more help.
Yes, I know just about all there is to know about building tongue
drums, however, it is very difficult to explain the process in words
with no visual examples. I was on a quest to discover the "secret",
too, in 1995. I finally had to buy a very nice, EXPENSIVE example of
one and used dental mirrors to see exactly what was happening on the
inside. The "secret" was easy to see, but, but when I went to build
one, I soon realized that there was a certain order of operations that
had to happen if the drum was to be in tune when all the clamps were
finally taken off. These drums are extremely difficult to do
correctly. The are rather easier to do incorrectly.

Tuning the drums is tedious to say the least! The ends, top and bottom
must be assembled first -glued tight, but the sides are left off until
the tuning is completed. This is essential.

The ends must be twice the thickness as the top. I sandwiched two
pieces of wood for the ends to achieve this.

The top board (the one with the tongues cut into it) must run the full
length of the box so that the end-grain of the top is visible....in
other words, the top "caps" the ends.

The shape and width of the tongues, themselves, is not so important
-you mainly just want to make them different lengths. The major potion
of the tuning happens on the underside of the tongues by removing wood
at the fulcrum point.

With the top, ends and bottom glued into place (precision joinery is
essential -no gaps), you will see, on the inside, the fulcrum point.
Each tongue has a separate fulcrum point. Wood is removed a little at
a time from the underside of the tongue, near where it abutts the
ends, so that it can become "springier", if you will. The wood is
removed with a very sharp chisel.

Each time you take some of the wood away from the underside, you must
temporarily clamp the sides in place and check the pitch, take the
sides back off the box and remove the wood until it reaches the
correct, desired note. Keep in mind, you can remove just a shaving too
much and ruin the note. It's very important to go slow and remove a
small amount of wood each time -especially when you start hearing the
note getting close to the right note.

The basic idea is to have the front of the tongue be more massive than
it is at its fulcrum so that the notes can sustain. Low pitches
require a long tongue with a fair amount of wood removed from the
underside of the tongue near the fulcrum. Higher piutches require a
shorter tongue with less wood removed.

Once you have all the notes tuned, then the sides can be glued in
place and final finishing can be done. Keep in mind, though, you will
want to do all the construction as meticulously as possible so that
you avoid having to sand too much of the wood away during the
finishing process -as this will change the pitch. After the box is
glued up, there is no turning back for pitch adjustments.

You can fumble with all the algebraic formulas in the world, but you
are dealing with an organic material and that makes any kind of
predetermined calculation pointless. Use you ears and tune the drum to
an electronic keyboard or some type of pitch generator that can give
you an A=440. It's a process of tedious trial and error.

The best woods to use for tops are:

Paduak, Canarywood and Wenge.

You can use cherry, maple, walnut, etc for the ends and sides. Don't
use anything really soft, though as this will have a muting effect.

Use woods with straight grains for the tops, i.e., no burls, etc. You
will find that, sometimes, when you are cutting the shapes of the
tongues, it may release the wood from some of its internal pressure
and the tongues may spring up or down on their own. Using stable,
straight-grained pieces will alleviate most of this tendency.

Good luck! You will need it. It's easy to make an "okay" tongue
drum...It's VERY difficult to make one that plays in tune with
resonant tonality and notes that have bell-like sustain.
Mike
2004-01-07 16:43:37 UTC
Permalink
Post by O-Lugs
Yes, I know just about all there is to know about building tongue
drums, however, it is very difficult to explain the process in words
with no visual examples.
I deeply appreciate your explanation and the time it took to type out.
Thank you very much, I know I will be reading over this many times
when I am finally ready for the construction (I have to wait to visit
the in-laws' since I live in an appartment and have no workshop...or
tools, hehe).
Post by O-Lugs
The top board (the one with the tongues cut into it) must run the full
length of the box so that the end-grain of the top is visible....in
other words, the top "caps" the ends.
That is very good to know. It is interesting that in all the research
I have been doing on the Net, I have noticed that many examples I have
seen do _not_ do that. I have seen many that are the opposite:
meaning that the sides and ends cover the edges of the top piece!
Post by O-Lugs
The basic idea is to have the front of the tongue be more massive than
it is at its fulcrum so that the notes can sustain. Low pitches
require a long tongue with a fair amount of wood removed from the
underside of the tongue near the fulcrum. Higher piutches require a
shorter tongue with less wood removed.
I take it that I would wnt to go for the more common "tongue shape"
tongues rather than rectangular tongues?

Do you have any suggestions for tuning the box to a concert C? My
idea is to make a tongue drum to act as an organic timpani, with
either 2, 3, or 6 tongues (either the C [root] and G [fifth], same
plus an octave C, or a C pentatonic with octave C). So I am talking
about a C at 65.406 or even 32.703! If I want to get that low, how
big should I aim at starting off with? I wouldn't want to make the
tongues too big that I end off having to shave alot off of the ends,
as I am sure that would open up the top too much (is this something
to be concerned with?). I also don't want to make the tongues too
small that I have to shave alot off, thus weakening the tongue too
much.

Again, thank you for your informative and well written post!

Mike
O-Lugs
2004-01-08 00:02:22 UTC
Permalink
Post by Mike
Post by O-Lugs
Yes, I know just about all there is to know about building tongue
drums, however, it is very difficult to explain the process in words
with no visual examples.
I deeply appreciate your explanation and the time it took to type out.
Thank you very much, I know I will be reading over this many times
when I am finally ready for the construction (I have to wait to visit
the in-laws' since I live in an appartment and have no workshop...or
tools, hehe).
Post by O-Lugs
The top board (the one with the tongues cut into it) must run the full
length of the box so that the end-grain of the top is visible....in
other words, the top "caps" the ends.
That is very good to know. It is interesting that in all the research
I have been doing on the Net, I have noticed that many examples I have
meaning that the sides and ends cover the edges of the top piece!
Post by O-Lugs
The basic idea is to have the front of the tongue be more massive than
it is at its fulcrum so that the notes can sustain. Low pitches
require a long tongue with a fair amount of wood removed from the
underside of the tongue near the fulcrum. Higher piutches require a
shorter tongue with less wood removed.
I take it that I would wnt to go for the more common "tongue shape"
tongues rather than rectangular tongues?
Do you have any suggestions for tuning the box to a concert C? My
idea is to make a tongue drum to act as an organic timpani, with
either 2, 3, or 6 tongues (either the C [root] and G [fifth], same
plus an octave C, or a C pentatonic with octave C). So I am talking
about a C at 65.406 or even 32.703! If I want to get that low, how
big should I aim at starting off with? I wouldn't want to make the
tongues too big that I end off having to shave alot off of the ends,
as I am sure that would open up the top too much (is this something
to be concerned with?). I also don't want to make the tongues too
small that I have to shave alot off, thus weakening the tongue too
much.
Again, thank you for your informative and well written post!
Mike
Wow! You're talking about some LOW pitches! I have never built one
that would be big enough to produce tones that low....I have kicked
around a few ideas for a HUGE drum, but the construction would have to
be slightly altered. This may be quite an expensive undertaking
because tropical hardwoods are quite expensive. I highly recomend that
you build a smaller version first so that you can get a feel for all
that is involved.

The drums I built were relatively small -the largest one being a
10-note, double-ended drum that was approx. 15" long. The longest
tongue was about 8-9". These sound similar to a marimba -but with more
sustain and clearer bell-tones. The WIDTH of each tongue is approx.
3/4"-1". BUT! If you plan on making a huge drum with super-low
pitches, you may have to adjust thewidth so as to give you some kind
of strength at the fulcrum. The more wood you have to remove from the
underside of the tongue at the fulcrum will also weaken that area
significantly unless some extra width is given.

To make a big tongue drum, yo will probably have to construct the top
from individual pieces of wood and glue them together with spacers
separating the tongues. Plus, I suspect that the depth of the
resonating chamber (the box, itself) will have to be made deeper so as
to allow the longer waves to develop inside that chamber. A shallow
box will "clip" the waves and diminish resonance.

If you would like to continue this discussion, please go to
http://www.Drumsmith.com. That is the site I regularly post on, but
they are having some problems with their web server and have been
offline for quite awhile. They WILL be back, though.

Good luck.
Phil Price
2004-01-10 12:28:32 UTC
Permalink
I have no tips for tuning slit drums, but I have some other tips that might
be handy.
I paid my way through Uni by driving a taxi, and building slit drums, 450 in
total.
Make me some sort of expert I guess.

Essential that you use quarter sawn timber for the top.

The grain of the ends of the box needs to be vertical so that it moves with
the top of the box.

A 3/8" inch hole drilled on the top where the slits will end makes cutting
the slits much easier, plus it makes for a better tone.

Make the 4 slits 13" long. Cut the six tongues (from the right) at 8, 4 ,
and 7 inches.
this makes tongue length (from the left) 5, 4 and 6 inches. This
measurement ignores the Comma of Didymus if one is fussy about the tuning.
It sound okay, trust me!

It needs to have feet for best sound. I drilled into the corners about 3/4"
with a 3/8" bit, inserted 1 1/2" dowell and fitted chair tips on the stub of
the dowell. This makes a BIG difference to the sound quality.

BTW. I called my slit drums "Aztec Drums." but sales were so-so. My sales
skyrocketed when I renamed them ..................?
Mike
2004-01-12 18:34:22 UTC
Permalink
Post by Phil Price
The grain of the ends of the box needs to be vertical so that it moves with
the top of the box.
A 3/8" inch hole drilled on the top where the slits will end makes cutting
the slits much easier, plus it makes for a better tone.
Hi Phil, thanks for the info. Should the holes be at the ends of each tongue?
Post by Phil Price
Make the 4 slits 13" long. Cut the six tongues (from the right) at 8, 4 ,
and 7 inches.
this makes tongue length (from the left) 5, 4 and 6 inches. This
measurement ignores the Comma of Didymus if one is fussy about the tuning.
It sound okay, trust me!
What is the "Comma of Didymus"?
Post by Phil Price
It needs to have feet for best sound. I drilled into the corners about 3/4"
with a 3/8" bit, inserted 1 1/2" dowell and fitted chair tips on the stub of
the dowell. This makes a BIG difference to the sound quality.
Oh, that _is_ good to know. Did you use plywood for the bottom piece?
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