>> Yeah thanks very much Jim.
Thanks everybody for
coming along today
and everybody watching
on the web over there.
I guess I'll let the guitar
do the talking for a start.
[ Playing guitar ]
[ Applause ]
Okay we're going to over
it in a little while.
And there was a reason we played
that and we're going to talk
about the projection and
such of these guitars.
So, that there is one of
the latest and greatest
of the ones I've made.
For those of you who've known me
a while you know this is pretty
much what I do.
It's a great privilege to be
able to talk about guitars
in front of some of my
colleagues that shout me
down quite often because I'm
always talking about them,
living them, breathing them.
Thanks Mark.
So, today's talk is titled,
"Making Guitars with
a Physics Mind."
And it was really interesting
putting this presentation
together, the realisation I
guess that I've come to find
out about myself and the
sort of things that I do
when I'm making guitars.
I've seemed to absorbed a
lot of stuff through my skin
and not able to sort of quantify
or talk about the principles
that I'm discovering
and trying to apply
in the way I make these things.
And a great example of that
is if I ask the audience here,
what is it like to
see the colour red?
And you really can't
put that into words.
But, I guess with a physics
mind oh yeah, of course,
colours have different
wavelengths
and red has a particular
wavelength
that it reflects off objects
and therefore we see red.
It still doesn't answer that
question, what do we feel or see
when we see the colour red?
It's really hard
to describe that.
And so what I've discovered
in putting this presentation
together is the physics has
allowed me a language
now to describe some
of the things that I'm doing.
So, that's a very
important point.
It's not like I pull apart the
guitar and quantify every part
of it, tune everything to
certain resonant frequencies
and thinking this is
a great way of going
and then put it back together.
I actually make the guitars
really based on intuition
and I guess empirical
knowledge that I've gained
from previous manufacturers who
share their knowledge via books
or internets and
things like that.
And once I've absorbed that
and know what I'm doing I can
then quantify what I'm actually
really doing in physics terms.
So, that's a fairly
important distinction
that I'm not just simply
making things by formulas.
That's my cave there.
That's where you can find
me between six o'clock
and eight o'clock every morning
of the week and a lot of times
on evenings and weekends
as well.
I'll talk about string
vibrations
because after all
that's what we used
to put the energy
into a guitar body.
If we just had a string on its
own it won't make much sound
at all in that's directly
related to the amount
of air that it'll move.
The string's a fairly
thin thing.
It can't move much air
so we don't hear much.
A guitar isn't an
amplifier of the sound.
That's a really bad term to use.
It certainly doesn't do that.
In fact, the guitar is a real
waster of the energy budget
that you put into it
with the strings' energy.
It really does waste
that energy.
But, we try as best as
possible as guitar makers
to make the most
efficient use of the energy
that you have got there
and hopefully not too
much of that is wasted.
So, in broad terms this
is just an introduction.
The guitar will resonate at a
whole spectrum of frequencies
and the whole of the
guitar will vibrate.
As a player on a really well
made handmade instrument you'll
feel the neck moving.
You'll feel the back moving.
The whole of that guitar is
actually in motion at the time.
Another thing that happens
as well is it goes in and out
like a bellows and so
it's like an air pump.
And so the sound also emanates
from the sound hole as well.
So, it's radiating from
the surfaces of the guitar
and it's also coming
out of the hole there.
[ Silence ]
Some basic physics here,
how the strings vibrate.
This does lead onto
other aspects.
You're probably very familiar
with things like fundamentals,
first overtones, second
overtones and third overtones.
And this is something I'll
be talking about later.
And we can actually force
those modes on a guitar.
If I was to go halfway
between the guitar here
and pluck the string
right in at centre,
funnily enough those two
dots have been put on there
for the player to know that.
Have a listen to the sound,
having a lot of buzzing.
I can't stop that because I'm
really exciting the string
at its middle here.
It's a very round tone.
If I pluck the string right
at the back now what I'm doing
actually is I'm exciting first,
second, third and higher
overtones to the string sound.
So, that would sound like this,
compared with something up here.
So, you can immediately
see there's a difference
in the way you play the guitar.
And of course, some players
might even strum the guitar
halfway along the neck for
particular sounds and effects
as opposed to further back here.
So, the player themselves
actually influence quite a bit
what the guitar will sound like,
in fact an extraordinary amount.
You don't just get
a fundamental.
You don't just get
a first overtone.
You get a whole mix of those.
And so if we just took for
instance the first overtone
and fourth that would
be a resultant waveform
and algebraic addition
of those two.
And of course, there's a long
series of these harmonics
and depending on the
type of manufacturer
of the string depends
on what kind
of harmonics you might
expect on that string
and also the weight of that.
It's the harmonic
series that's responsible
for the unique sound quality
of different instruments.
And did I bring it along?
I just invite everybody at the
moment to indulge me just to--
it's too late now, because
you've probably seen
at the front what I've got.
If you can just close your
eyes for a minute I just want
to play a note on a
particular instrument and see
if you can tell me what kind of
instrument's making this tone.
[ Silence ]
[ Music ]
By the way, it's not a
strangled cat at all is it?
Okay so without even
seeing that instrument--
hopefully those at the
back never saw that.
You can tell instantly with
that kind of harmonic spectrum
that thing is a violin.
Instantly you know that.
If we look at a guitar
where does all this
transfer of energy happen?
It happens at the
place called the bridge
and also the saddle is
that little white
piece sitting in there.
And high quality instruments
will make that out of bone.
And so, it's the
bridge and the saddle
that essentially are the
energy transferring components
of the guitar where the
first bit of energy comes
from the string and goes
into the guitar body itself.
They tug at that bridge with
their unique harmonic spectra.
That's not to say the
guitar's going to vibrate
at that unique harmonic
spectra at all.
It's just that's what's
available in its energy budget
to then be distributed around
the guitar in whatever way
that particular guitar
will respond.
[ Silence ]
Okay so I'll just-- we'll
go back a few steps now
and I'll work back up to the
slide that we just showed.
Wood is the engineering
material you use.
And wood is always on the move.
It's a very, very humid day
today and I had to retune all
of these instruments
because they move around.
Wood will absorb the
moisture in the atmosphere
and similarly it will dry out.
And so the parts of the
guitar will actually distort
with these different humidities.
When you go to Bunnings have
a look at the top plank there,
plank number one that's
nice and buckled and bowed.
Strangely enough Bunnings have
quite a number of those planks
in jarrah and things
like pine for sale.
What the wood does is
it actually cups away
from the centre of the tree.
So, if you ever see something--
a wood bending like
that on the bottom
of the radius you know that's
the bit that was closest
to the core of the tree
and the reason being
that the wood will
shrink primarily
between its growth rings.
The kind of wood that
you want to make a guitar
out of is the plank indicated
by number two over there.
That plank there is what's
known as quarter sawn wood.
If we were to slice that log
into quarters and then take one
of the-- a board off the face
of the quarter, so we'd slice it
into quarters down this way
then we've taken a board off one
of the quarters.
The only that piece of wood
can move now is in and out.
It can't flex up
or down and bow.
It only can go in and
out with moisture.
So, that's a reasonably
stable bit of wood.
I've brought along a few bits of
wood just to show what I mean.
This is a bit I've
bought from Bunnings.
Isn't that lovely clear timber?
Not really, knots
all over the place.
But, you can't really expect
much else out of this.
This is pine wood.
And what I've-- when I go
purchase wood I do look very
carefully at the
ends of the grains.
And just here and it's very hard
to see, is the core of the tree.
This is the centre here.
And out here are the growth
rings radiating out from that.
So, this particular piece of
wood even though I bought it
as a throwaway piece for some
of the things I was doing,
I made sure it was at
least quarter sawn.
So, I went through the
stacks of wood and got a bit
that okay it has a few knots
on, but at least this is going
to stay relatively flat for me.
I think I'll-- yeah in a minute.
We'll just show you
some other wood.
This is the kind of wood that
you hunt through wood stacks
for as a guitar maker.
You can see that I can't
really see any discernible
ingrain here.
It's very hard to
know what's going on.
And usually if I go to
these wood yards I'll ask
if I can saw a little piece off
the end or bring my plane along
and just plane the ends so
that I can have a look here.
And this particular piece
of wood even though no one
in their right mind would pay
21 dollars for something that's
so rotten is an excellent
piece of guitar wood.
We'll see that shortly.
And for me, this heartens me.
I know this was a fallen tree
that I've now reclaimed
from the forest.
So, we're not just tearing
up tropical hard forests,
hardwoods there for that piece.
[ Silence ]
Why do you get such
poor cuts in wood?
Of course, it's got to
be sawn for economics.
So, you don't want
to go wastefully
sawing wood in quarters.
It's a very wasteful
way to do things.
And they have come up
with various schemes.
I've just illustrated some
here for cutting these woods
and trying to maximise the, I
guess the yield from the wood.
And if you look through all
of those pictures you could
probably see quite a few planks
and all those different
cutting methods
that would yield suitable
wood for guitar making.
So, you do spend a lot of time
hunting through stacks of wood,
annoying these wood
keepers and going
through their stack again
and again and again.
As well as being quarter sawn,
it's an interesting phenomena
of trees that aren't
always straight grained.
What we mean by straight grained
is that the tree has just grown
up with no twists in it.
This is a reasonably
rare phenomena.
I've got two straight trees
out in the front of our house.
They're both weeping
peppermints.
One is ramrod straight,
no problem at all.
And the other has an
extraordinary twist on it.
So, these were two trees
grown at exactly the same--
planted at the same time, grown
in the same location, same soil,
same watering and yet they have
such different characteristics.
Why they do this is they
actually follow the Sun.
So, in the southern hemisphere
here a tree that's looking
at a northern facing
Sun will follow that Sun
and track it through the day.
Oh it disappears.
Oh here it is again.
And it'll follow and track
that and actually grow a twist
in an anti-clockwise fashion.
Guess what happens
in the northern hemisphere,
the opposite.
And why are tropical
hardwoods sometimes
so valuable and stable?
It's because they twist
one way and then another.
And so they'll just twist back
and forward and work their way
up and be very, very
straight grained
for a long distance
up their trunks.
So, as best as possible if you
can, you'll actually cut wood
for guitars out of
split billets.
So, someone's cleaved it with an
ax that's followed the natural
split line and then you resaw
the board to follow those lines
and that will yield
very, very stable wood.
Wood used for guitars ideally
have a very high stiffness
to weight ratio and
that's why I've hung
onto these two bits
of wood here.
So, here's our Bunnings pine.
We're a student.
We want to make a guitar, so
we'll buy some cheaper wood
and see what it might
sound like.
So, if I grab the wood, usually
about a third down its length
and just give it a nice rap
with my fist you can
usually see the sort
of tones it might produce.
That's quite subdued.
I didn't get that
tone this morning.
That's not bad.
And then we'll grab
our piece of rosewood.
I'm trying a similar
thing to that.
And this will rattle around.
There's lots of rot in this one.
The sustain in that's a lot
more even though as I say
that there's a lot of
rattling around there.
So, I go around the wood yards
not only planning their bits
of wood, sawing off the ends
and looking at the end grain,
but I go around there bashing
them with my fists as well.
What I am listening
for is things like,
you hear that rattle.
I'm listening for cracks
also in the billets of wood.
We don't want to have any
hidden cracks in there.
But, the amount of sustain
in that wood would tell me this
will make a great guitar back
and side set.
The wood that's illustrated
over there
in the picture's been
all sawn up by me now,
but this is all wood
I've selected for back
and side sets using
exactly that principle.
So, I've gone to the wood shows
as it turned out in Perth,
purchased those just by
bashing them and seeing
if they were resonant or not.
So, rather than sticking to
traditional timbers I go out
and just look for physical
properties of the timber.
I'm not particularly interested
in reputations of
historic woods.
So, if you want to
find stiffness
to weight ratios this
is how you can start
to quantify some
of these things.
You basically look at
the density of the wood
and its modulus of elasticity.
And I've illustrated these
four woods in particular
because they are the premium
and premier woods used
in the guitar building industry.
Spruce, whether its Sitka spruce
or Engelmann spruce or all sorts
of subspecies, Alpine spruce
from Europe is a very,
very good soundboard material.
And far and away, although
the numbers don't suggest far
and away, it is the
best stiffness
to weight ratio you could
ever get in the wood family.
So, it's just like balsa wood.
It's extremely soft.
Trust me, you have a little
sand grit or grain on your bench
when you're working it and put
it down on top and it'll indent
into that very nicely.
So, it's a very soft wood,
but extraordinarily stiff
and extremely resonant.
So, it's used for the
soundboards for pianos,
for soundboards for violins and
soundboards for a whole host
of musical instruments.
A good second-- a very popular
timber is Western Red Cedar.
We actually have an
example of some here.
This is a cedar soundboard here.
It's been manufactured
at the moment.
This just has a more
subdued colour.
Not as bright white.
And this is imparts quite a
lot of warmth to the guitar.
It's not as stiff as the spruce.
And so the bass notes here are--
it's easy to get a good
bass sound out of something
like Western Red Cedar.
So, that's usually used for
lower tension instruments.
You wouldn't put that in a
high tension instrument at all.
And back and sides woods are
the two bottom ones here.
Mahogany nowadays, Brazilian
mahogany is site certified,
so it's an endangered species.
It's no longer able
to be exported
from Brazil and South America.
Whatever's around is around now.
I was very fortunate
recently to purchase some.
I didn't-- it wasn't very large,
but I've made some necks
recently out of this timber.
Very nice timber to work and you
can see why it was so revered,
but unfortunately
so heavily forested,
logged and it's pretty
much all gone now.
But, that's a very,
very good timber to use.
And there's a number of mahogany
variants that are very good,
African mahogany and some of
the Asian species are very good.
But, this is the old
Brazilian version here
and you can see it's stiffness
to weight ratio is quite high.
The premium wood by far for back
and side material is rosewood
and in particular would
be Brazilian rosewood.
That was site certified in 1972.
So it's pretty rare to
find a guitar nowadays
or to find that wood.
If you do they're
actually cutting it
out of old tree stumps.
And so the sort of grain,
the nice straight grain
that follow the split
line sort of rules,
they're out the window.
What they're relying on there is
that people will buy something
that you can't get anymore.
And there's a lot of mystique
associated with that wood.
But, personally I would never
make a guitar out of it.
It would be way too risky.
As an example, here's
a very similar timber.
I've had this for
years and I wanted
to make a guitar out of it.
And this was a set
of sides I made.
And this is the sort of
thing you might expect
out of Brazilian rosewood.
It's-- it looks reasonably
straight and clear grained,
but it's certainly not.
And this thing is that cranking.
You couldn't bend this
thing with any sort of luck.
And I've just put this aside
as a bit of a bad loss.
So, it was-- that was a shame.
I had a big board of it all cut
up and I've still got it all cut
up and it's going
to remain cut up,
so not made into guitars at all.
Okay guitar anatomy;
what's inside a guitar?
Someone recently was very
surprised when I told them
that what you see on the outside
of the guitar really isn't much
to do with what makes
them produce the sound.
And when they poke their head
inside the guitar they were
astounded to see the
amount of wood work
that goes on inside there.
And to be honest, what's
under the hood is the most
important part of the guitar.
Here's one-- here's a guitar
I haven't prepared earlier
because it's still in pieces.
Bob Coleman down in the back's
about to become very intimately
acquainted with this guitar.
This is his guitar.
So, here's the internal
structure here
that I've been working
on for him.
These are the struts or
the braces and we'll go
over their function in a minute.
And there's a few little
hacks and chisel marks.
It hasn't quite been
finished yet.
But, this is a guitar top
that I'm slowing
carving away the braces
to get a nice tap tone on it.
Doesn't sound very
much to you guys,
but last weekend this
was extremely stiff
because the braces
weren't carved
and it's slowly opening up.
I've got to now decide
how much wood to take away
from this before it's
opened up enough.
And you'll see shortly if
I open it too much it'll
actually break.
Here's the back of the guitar.
These braces haven't
been shaped.
They're still in their
rectangular form.
And even so, don't know what
that truck's doing out there.
You can still get a reasonable
tap tone from something
like that that still
hasn't been carved.
Okay apparently we're okay.
Oh there we are,
very good Glenn.
Thank you very much
for your assistance.
So, we're going in.
So, there's the struts
you see along the back.
Have a look how I've
tucked those
in under those linings there.
So, those back braces are
actually coupled to the sides
of the guitar and
held quite firmly.
There's the backblock.
The big piece you
put the strapping to.
There's another one
tucked in over there.
Here's another one.
Oh nice woodwork.
Don, very good.
The biggest thing with
all of the little cuts,
the bit I'm coming really close
to now is called curthed lining.
We'll see a slide of that later.
And that's actually quite a
critical part of the guitar.
Every one of those cuts
believe it or not is almost cut
through that piece of
wood, but not quite.
And it's all done by hand.
So, it's been a very enjoyable
experience making curthe lining.
And I think Bob Ross here
has had a turn at that
and would have to agree that
that's just fantastic fun.
If we just back up
a bit it's going--
I might have to do
a bit of bending.
He's up. We can just
see the tops of some
of those soundboard braces.
Oh there's another
scheme for making sure
that they're anchored
quite nicely
and this is the way
we do it on the tops.
We actually stick one of those
little curthe lining blocks
on top of the brace to hold
it in there quite firmly.
It's an important point
of the guitar as well,
how thick that little
bit of brace is that goes
into those linings in there.
And I think if we back, back--
no we're not going to see that.
No. I thought we might be able
to see the strings coming in.
Okay, so there's a little
bit of a different way
to look in the guitar.
Oh if this works I'll be amazed.
[ Tapping sounds ]
[ Silence ]
Fantastic, smooth as.
Okay, here's one I
did prepare earlier.
What I do when I make guitars
like these things,
this is a cutaway.
But, in particular it's a
Venetian cutaway rather than--
I don't know why they call
it a Venetian cutaway.
A Florentine cutaway has
a smooth flowing curve
that you bend into it.
These supposedly
are harder to make
and I guess I have to concur.
They are fairly difficult
to get right
and make everything
look nice and crisp.
And what I've done when--
I usually make the guitar
as a solid guitar first
and actually hack into the
side and cut that part out.
And here that allowed me-- you
can just see the bottom edge
down there of where
I've cut it out.
That allowed me to poke a camera
in there and get quite artistic.
So, you can see the internal
structures of that one there.
This is about to be
strung up and working.
So, those braces there are
at the correct thickness
and weights and resonance
and everything
that I wanted about them.
The finish has also
been put on as well.
So, I'll refinish after I've
put the cutaway in there.
So, I can judge-- I could have
stuck my hand in after this,
after cutting it and
actually adjust it
or taken some wood away from
those braces if I had chosen to.
So, it does allow a little
bit of luxury that way.
Here's another look at them
when the backs are not on.
So, this is the soundboard
bracing.
This is specifically for
steel string guitars now.
It's about 700 Newton's
of tension.
So, about the standard
physics person,
that's 70 kilograms standing on
a rope, hanging off that bridge
for the life of the guitar.
So, it just gives
you an appreciation
of how much force is on the
guitar, on the guitar top.
And it turns out you don't
even need those braces.
You can make a guitar
without the braces whatsoever.
So, that's quite a surprise
I'm sure for a lot of people.
What would it sound like?
Horrible. What would
it last like?
Probably a month or two before
it would collapse in on itself.
So, it wouldn't hold
up to long-term tension
and it wouldn't sound
very good at all.
Why is that?
Well, most importantly on
the right of the image there,
braces increase the
stability of the top.
That's very important.
But, most importantly
they control the modes
of vibration of the top.
And this is something that
certainly I've learned
since my previous talk here
in the physics department
that that's really the
main purpose of braces
and brace schemes is
to control the modes
or the way the top will vibrate.
Yeah sure, it also has
the secondary function
of keeping them held up
over a long-term tension.
But, it's really the modes
of vibration that's
very, very important.
What am I talking about modes?
This is a bit of a go at
trying to have a graphic
to show what modes are.
And so if you can imagine red
being out perhaps and blue being
in this is the type
of oscillation
that the monopole
mode is on the guitar.
So, that's in and out type of
bellows movement and this is
where we get the sound
coming out of the sound hole,
sort of helm hole;
it's resonator style.
The monopole mode in
steel string guitars
because they're made of jangly
steel is a very important one
to get right.
What we're trying to do in steel
string construction is increase
the bass response.
And if you make the monopole
large, a big monopole
where the whole thing can
move in and out as a complete
and total unit, then you can
increase the bass response
and get a nice rich bass
response on the guitar.
So, the monopole is
certainly something
that I'm constantly
striving towards increasing.
There's two other main types.
This is the cross dipole mode
where you've actually
got the bridge teetering
on itself going backwards
and forwards.
And this is extremely
important in nylon
and classical string guitars.
This is the mode that they
primarily are interested in.
Nylon strung guitars
have great bass response.
The thing they struggle
for is treble response.
And so this mode here
gives great treble response
and also actually as it
turns out aids in projection.
If I play a guitar a
long way from somebody
and they can hear it
very clear, then you know
that we've got the cross
dipole mode very active
on that particular guitar.
These aren't exclusive
of each other just
as the harmonic spectra of
frequencies weren't exclusive.
We don't just get
the fundamental mode.
We get a whole mixture of these
modes on any one guitar top.
And then the final one
is the long dipole mode.
This one's a bit
difficult to get going
because of the way you've
orientated the wood.
You've put a lot of
stiffness in that area.
And so the long dipole mode
where the bridge teeters back
and forward on itself is a
hard one to try and enhance.
If you're trying to
enhance that one you tend
to weaken the structure
a little bit
and over a long-term the
guitar will fall apart.
So, that's not going
to be a very good one.
But, that one is
prevalent and is used.
So remember, there's
a mix of all of those,
but just like we
had the fundamental
in the first overtone we've
also got similarly fundamentals
and first overtones of these--
of the dipole modes,
not of the monopole.
So, we can also get the top
breaking up into two area--
with two nodes or three
nodes or four nodes,
etc. And so actually
the movement of the top
on a guitar is actually
quite chaotic.
It's a very chaotic
thing indeed.
And remembering that
this is the sort
of bracing scheme we've got.
So, it's not a homogenous plate.
We've got braces placed in
very specific places here
to enhance very specific modes.
So, we'll just have a quick look
at nylon string soundboard
bracing.
And if you remember, what
they want is the cross dipole.
They want the bridge
to rock backward
and forward on each other.
Look at all the bracing schemes.
They all brace in
that long fashion.
They all want the bridge; they
want to enhance that bridge
to move backwards and forwards.
Interestingly you might not
intuitively know that down
in the bottom right hand side
is a guy who lives in Esperance,
and he has this lattice
brace arrangement.
He has probably some of
the more innovative ideas
on classical guitars.
But, his bracing system as well
very much enhances that dipole
and he's very aware
of that as well.
So, it's not as intuitive
on his style of bracing,
but that's what he's doing.
So, that's the realm of
classical guitar building
on nylon strung guitars.
That's not my realm.
My realm is steel
string construction
and very specific kinds
of steel strings as well.
This is the bracing pattern--
it's not the only bracing
pattern you can use.
But, this is the bracing pattern
that I base everything
that I do on.
It's known as the X
brace pattern mostly
because of two main braces
along there, the two main X's.
The good thing about
this bracing system
in steel string guitars
is it really does tie the
whole structure.
So, to get that monopole mode
going it's very easy to do.
The thing you see on the
top of the guitars here,
the brown thing, is the most
important brace on the guitar.
It's the only one that's
on the outside too.
But, this bridge here
actually ties those legs
of that X brace together
by its exact placement.
So, you can see that
on the diagram.
There's a bridge plate and
there's a little tiny outline
of the bridge itself there.
And if you were making a gate or
some sort of a structure at home
and you had two cross pieces of
wood wouldn't it be advantageous
to stick something across to
tie those things together.
So, it's able to tie
that together and get
that monopole mode
going really nicely.
But, the good thing about the X
brace is we can open and close
up the X, not by much,
by very minute amounts
and we can actually increase
the amount of long dipole
or cross dipole modes
that occur on there.
And we have auxiliary braces.
They're just called
finger braces,
although these are
called soundboard braces.
I just call them finger
braces that come off here.
And they're also
important as well
as the lower transverse braces
in just helping control some
of the spectra that we see.
If we have a look
at this guitar,
this is actually a
small body guitar.
So, we'll just go back
to that soundboard.
And it's a very lightweight
cedar top
that can't handle
much string tension.
And what I've done here is
modify it a little bit what we
might see over on
the slide over there.
So, I've eliminated a second
finger brace from here.
I don't want to stiffen
this top up at all.
And I've only got one
transverse brace and look
at the orientation I've put
rather than having it hang right
down the base of the
guitar down here.
So, what I'm trying to
do as much as possible
with this guitar, it's a
small body and I'm going
to fighting getting
a good bass tone.
So, I'm trying to open
up the top a little
bit more artificially
by removing any weight down here
so that the thing can get a bit
of a long dipole, but hopefully
a really good monopole movement.
So, hopefully I've tied the
structure together really nicely
with the arrangement
of braces there.
So, the rest of voicing
this top, as it's known,
is just removing just removing
a little bit extra wood.
I'm almost there now, until
I can get a really pleasing
tap tone.
And although this is not fixed
at the sides like it would be
in a guitar this gives
you a quantifiable way
of knowing have you
reached your target tone.
Interestingly with
braces the buzzword
in braces is let's get a guitar
that has scalloped braces.
And so many guitar companies
offer scalloped braces.
What happened there was
in a factory setting the guys
would put the guitar together
slightly overbuilt, a little bit
heavier than it needed to be.
They would string it up and
go this guitar's a bit dead.
They'd reach in the sound
hole with their planes
and they would plane a
little bit of the braces
and they would just weaken those
braces up and string it up again
and try it again until
they got it right.
And so by slavishly
copying what people said--
saw when they opened
up the guitars
and saw these braces
were scalloped.
It's false.
You don't need to
scallop braces at all.
What you should be doing
is getting very skilled
at getting a very
nice slim taper
on the braces in
the first place.
So, I've yet to have any
of the guitars I've made
where I've thought gee, I really
need to get my hand in there
and start to carve away
some of these braces.
So, that was in a
factory setting
where basically they assume
all components are the same.
So, some guitars clearly
won't be the same as others.
[ Silence ]
Going back delving into the
physics why do I make the braces
or I just know that you
need to make them taller
than they are instead of
really squat fat ones.
Basic physics can tell you.
If you look at the brace
on the left hand side
if we make it twice as wide
we get twice the stiffness.
But, there's a squared rule
if we make it twice as high.
Sorry it's a cube rule.
Pick me up on that
would you hey?
It's a cube rule.
So, we get eight
times the stiffness.
So, when I'm mucking around
now removing a little bit
of wood here I can do a
lot of damage very quickly.
And one thing in guitar making
I've realised over the years
in making many guitars is
you can't put the wood back
on again.
And so when you're at this
almost target thickness here
it's very much a slow
process of removing a bit
of wood and testing it again.
You don't really want to try
and put that wood back on.
It's a really hard thing.
I've had one guitar in
the history of making
where I've basically run this
hole through my thickness sander
and taken all the braces
off again and started again.
So, I went a little bit too far
on that particular one so, yeah.
So, we like high braces and
the reason is we get a lot
of stiffness.
And the same happens with the
thicknesses at the tops as well.
So, if we make the top twice
as thick it will have
quite a lot more stiffness
than if we make it only a
little bit stiff, a bit thicker.
Domes, tops and backs
are a little bit
of a current trend
in instruments.
I've actually got a
mysterious instrument
that I had under here.
This is a violin
kit I put together.
I wouldn't say I made.
I just glued the components
together that I bought.
And it's well-known
in the violin world
that they carve a dome into
their instruments for strength.
So, these guys don't
have to worry too much
about the internal
bracing and structures.
They don't have complicated
bracing schemes here.
What they have is just a single
tone bar run down the middle
and not just controls
some of the modes
of vibration on a violin.
The back is un-strutted.
So, it's just carved
out of maple
and the top is carved
out of spruce.
So, this is a well-known of
getting larger instruments
like violas and double basses
to contain the stress here
that's put on by the bridge.
So, it's a very strong way
of building instruments.
The way you can do in a steel
string sense is in part a bit
of a dome to your instruments.
And this is the one
I played first off
and is a good example of that.
And it might be a
bit difficult to see,
but built into this
guitar has been a radius.
And I'm sorry to use the units,
but it's a 40 foot radius.
And in the back of the
guitar has been built
in a radius 28 feet.
So, you do the math if you
like the metric system.
And this has been
done specifically
to increase the stiffnesses
of the woods.
If I can increase the
stiffness of the top
of guitars I can remove a lot
of the wood that I'm using
in the bracing structure
purely as a structural element.
I can then concentrate
on using the braces
as more controlling
in the mode element.
So, they're just simple
lightweight things
that are almost fixing the top
in certain positions
in that case.
So, earlier constructions I've
made and still do a little bit,
things like this guy here.
That's a true flat
string-- a flat top guitar.
So, that has a completely
flat top on it.
But, as it turns out you tend
to dome the backs as part
of the manufacturing process.
So, it's possible to make
guitars with flat tops as well.
They sound just as good.
It's just that I have to
be mindful now that it has
to be a bit more structural
in my bracing system rather
than looking at the
sound that I'm getting
out of the instrument.
[ Silence ]
Okay oh I just wanted
to-- how do I do it?
How do I put a dome
into instruments?
Here's Bob Coleman's back
there and this has a dome put
in it already like this.
I have a 40-- sorry, for this
particular one its 28 foot
radius dish that it's coated
completely in sandpaper.
And each of these braces
I've put it on the dish
where it will sit on the guitar
and sand the dome into that.
And then when these are glued
I actually press this bottom,
the bottom of the
guitar onto the dome dish
and have some sticks-- it's
known as a Go-Bar deck,
sticks that sit down
and press the brace
onto there while it's glued.
And then when I finally
get to stage--
you saw an open guitar
before without the back,
I'll actually turn the back
upside down on my sandpaper
and sand in the dome
into that as well.
So, when this is glued onto
it it's pulled completely
into a dome in all dimensions.
So, that's how we do that.
And the tops are done
in exactly the same way.
It's just that the dome in
those is a lot more subtle.
But, those at the front can
certainly see this thing's
teetering on quite a radius.
So, I'm able to now lighten
up those braces probably more
than I normally would
have been able to.
Seeing the unseen, these
images are being pinched
from the University of
New South Wales website.
Thank you very much for those.
And this is using
Chladni patterns.
So, we throw a bit of sand
on top of the guitar top
and where it collects is a node
point where there's no movement.
And you can start to investigate
what is the frequency response
of your guitar top?
This is done by a lot
of manufacturers as part
of their manufacturing process.
I'm personally not
interested in that at all,
but it's a very interesting
exercise if you do look
at the response of a guitar top.
Note also, this is a free top.
It's not being fixed to
the sides of a guitar yet.
So, obviously that would
be a completely different
response altogether.
Seventy seven hertz, this is
around the base E
frequency of a guitar.
And this one is quite
low and got a little bit
of that monopole activity
and as well as some
of that crossbow pole
activity, which is a good thing.
As the frequency gets increased
you can start to see more
and more complex patterns.
The first few seem to
stay about the same
and obviously the
soundboard breaking
up in all sorts of weird ways.
Remember the bracing system's
not symmetrical underneath
and that's controlling a lot
of what you're seeing here.
About there I think, I
think it's a bit lower is
that frequency, the high
E string on a guitar.
So, that's what the top's doing
and vibrating similar
to that I guess.
And as you keep sweeping through
these frequencies you can see
the tops breaking up into more
and more areas where
there's modes.
It's a pretty crazy
one isn't it?
Look at that.
Okay so that's what
the guitar top I guess
in some ways is doing.
It's like the string
breaking up into higher
and higher modes
of those dipoles.
As the frequency gets higher,
the frequency that's
driving them.
So, we talked a little bit
before about curthe lining.
We had a little bit
of a look at them
on the probescope
inside the guitar.
Here's the guitar with the back
off and those linings exposed.
I was told this by
a guy in America.
I went to Santa Cruz
Guitar Company
and the president was very,
very kind and gave Glenn Lawson
and myself a personal
tour of his factory.
He sat down at the end of that
and I guess had a quick brain
dump of some of his philosophy
to me and this is the
one that resonates
and has absolutely
stuck with me ever
since as being a true thing.
He used basswood for his
linings of the guitar.
And I asked him why?
And he said, "Well, basswood has
no preferred grain direction."
You can't really cleave
or split basswood.
It's a very interesting
wood that way.
And he said, "If
you use the basswood
for the linings you'll actually
isolate the top and the back
from the sides of
the instrument."
So, you should get minimum
vibration of the sides,
but the back and the front
will act more like a drum.
And he suggested I try and
concentrate on tuning those back
and top plates to each other
so that they'll actually
enhance what each other does.
And I've certainly found
and by playing his guitars
that is a very, very true thing.
The majority of manufacturers
still use mahogany linings.
They couple the sides and so
the energy budget you've put
in with the strings is a
bit lossy around the sides.
Guitar players appreciate that
a lot because they can get some
of the sound that they're
producing radiating
to them instead of going
out and being wasted
on their audience, alright.
What would you want
to do that for?
And this concept's been
taking a lot further nowadays
that people are cutting sound
ports into the top sides
of the guitar so the player
themselves can hear that music.
To me that's a little bit
odd and I certainly don't go
for those types of things.
It's very much defacing a
lovely looking instrument
and I would never put a sound
port in my guitars at all.
So, the basswoods lining
here, their function is
to isolate the vibrations
at the top.
So, the vibrations can
only get to the back now
through the interaction of
the airspace in between rather
than through the
sides primarily.
So, the role of the back
very, very important.
The back is a little bit like--
imagine an athlete
on trampoline.
They can start boinging away
and what they do with their legs
to get the maximum jump
is very much in harmony
with the resonance
of the trampoline.
But, if you've seen these
Olympic people once they've done
their time or their amount
of tricks they can stop
themselves instantly
by putting their legs at a
different resonant frequency
and just stop instantly.
This is exactly the function
of a back on a guitar.
So, the top will be
driving, being driven
by the strings vibrating
away happily, nicely isolated
by the basswood linings.
And if the back is in sync
with that motion it will keep
that motion going and enhance
the sustain of the instrument.
And this is something
for those--
possibly there's a
few guitar players
around here today
that own a guitar.
You can test this for yourself.
So, here's a back,
Queensland maple.
It's nice to promote
our local species.
You can tap those-- these things
and get a sense of
its resonance.
That's one way to test the back.
But, a really good way is
to play the guitar with it
against your ample
girth if you want
and then play it a little
bit further away and see
if there's any difference
in the sound.
And probably a nicer
way to do that--
let me just hook
my leg up somehow,
is if I just tap the
top rather than play it.
So, I'll tap it without--
against my body and with.
This guitar maker
knows what he's doing.
He's made that back
really a part of the sound
and that's an important point.
If someone wants a guitar
that they want to strum
in say a rock setting, a rock
band, they'll put a strap
on this thing and
they'll be standing up
and be playing it like that.
So, they're missing out
on all those frequencies.
So, if I'm designing
a guitar for a player
like that I won't bother
too much about the back.
The back might be
aesthetically pleasing,
but it's certainly not going
to help and enhance the sound.
So, the difference in playing
with it against me and away
so we just get a lot rounder
tone and much more muted.
And you can test a number
of guitars with that.
So, here's a mahogany back.
Mahog-- this is African mahogany
so it's a bit of a substitute
for the normal mahogany.
Once again a great report.
Fantastic and you can try a
similar thing with this guitar.
So, I'll just do the tap.
[ Tapping sounds ]
And take note of that name.
This guy really does know
what he's doing doesn't he.
Alright and the last wood here,
this one's probably
the most striking.
This is-- in sound as
well as looks I guess.
This is Tasmanian
Blackwood, which also occurs
on the Australian mainland.
This is actually fiddle
back so that's quite fancy.
But, that has a very,
very good tap tone,
extraordinarily good
stiffness to weight
so it makes a great
back material.
And similarly if we just
tap that one virtually dead
without it, this
particular guitar.
And this one has very much been
designed with that in mind.
So, this is what we'd call
a finger style guitar.
This is one that's
meant to be played
on the knee away from the body.
For something and I don't really
have a good example of that,
but I guess the best example I
have would probably be this one
here with Queensland
maple back and sides.
This is what I call
the rib tickler.
So, the guy would be standing up
and having it against their body
as they play the guitar.
[ Playing guitar ]
[ Silence ]
Okay bracing patterns in
backs, a little boring.
What we're trying to do is
enhance the long dipole.
And so primarily, these are the
bracing schemes that prevail.
I used to slavishly copy
what we see on old guitars
and put four braces across
here, but this is one
of the small body models and
I realised you didn't need
as much stiffness in these.
And so I've now gone to
a three brace system.
And these will be carved away
just like I do to the top braces
to try and get the most
resonance I can out of the back
so it's part of the
guitar sound.
So, apart from looks on a guitar
back it's very much a part
of the sound as the top is.
Scale length, there's
not much variation
in scale lengths of guitars.
Historic guitars-- why
did I bring this along?
Historic guitars were
these kind of things.
It isn't a lute.
It's actually an oud from the
Middle East, but it's very,
very similar to a lute and
it's the only thing I've got
to illustrate this.
This was what was used in the
olden days, the old times.
That was strung with gut strings
and they have a particular
kind of bridge here.
The bridge is actually
technically very boring.
It was not much thought
put into that.
There was a rule of
thumb that you put it--
I think it was one
ninth the distance
of the whole top along here.
This particular one
certainly isn't that,
but that's not a great place
to put the bridge at all
if you want maximum monopole
activity on a guitar body
or any musical instrument.
So, these things are
a quiet instrument.
They were meant to be played
in small rooms, ensembles,
in very, very quiet settings.
So, this is a really
inefficient machine, very,
very inefficient,
strung with gut.
And the scale lengths in
these were quite short.
So, they're a very quiet
instrument for a reason.
And as modern times went on
and we got to raucous bars
and things and people wanted to
be heard the scale length sort
of standardised and I have gone
metric, although I can't think
of that in my brain,
61 and 66 centimetres.
It's-- the most common scale is
the 25.4 inch as standardised
by the Martin Guitar
Company in America.
The steel string
guitar is primarily an
American instrument.
It was born over there.
And the shorter scale guitar
24.9 inches is commonly used
and Gibson Guitar Company quite
often uses those shorter guitar
skills as well.
What would the difference be?
A musician would know instantly.
If strung with exactly the same
strings a long guitar is going
to have more string tension.
Because it's got more
string tension the middle
of the string's going to
vibrate and buzz on the frets.
And so that's going to have to
have a little bit more clearance
between the fret board so
the action or the height
of the strings is going to have
to be a little bit higher
above the soundboard.
There's going to be a lot less
energy to move the soundboard.
Just lightly strum that
thing and you'll get a lot
of energy put into
the soundboard
from the longer string.
Definitely has a more
resonant sound and by
that I guess I'm talking
about more fundamental
in the string itself.
It's going to be stronger
and therefore it's going
to have a better bass response
than a short scale guitar.
I did bring a short
scale guitar along.
My daughters are very lucky.
When they were five
they got a guitar each
and this is my first
daughter's guitar.
This is an extremely short scale
guitar because she's a very,
very short scale person
she was five, alright.
I mean she's grown up and
this is a bit of small thing.
But short scale guitars
lack a lot of bass response.
Not much bass response.
But, what they do have
is a really sweet treble.
And back to the basses,
which are very weak again.
There's another reason
and you'll see shortly why this
has a fairly weak bass response.
But, that's what a short
scale guitar is like.
It's very tiny.
There's no doubt about that, but
you won't get treble sounding
like that on a normal size
guitar with a normal scale.
Okay we'll get something
with a longer scale now.
There's rhyme and reason why I
brought everything along today
I think.
So, this is a tambura
from northern India.
Quite a long scale length
you'd have to admit.
And the good thing
about this is rather
than getting a bass guitar,
which is obviously strung
with big thick rope strings
played by Neanderthal types.
This one's a little more
subtle with very thin strings.
And this is used a backing for
the vocalist in Indian music.
And with very little energy the
strings just keep going forever,
quite nice to annoy
your spouse with.
This has been a-- look
forward to her trips to Sydney
so I can play this thing.
And so, tiny amounts
of energy in here
in actually a very
inefficient sound box.
The thing is a pumpkin, right.
I've got a pumpkin and I've
stuck a big heavy piece
of rosewood on with a big
heavy stiff arch on it
and I've just pressed the bridge
against it in violin style here.
So, it's an extremely
inefficient generator of sound.
But still, with a long
string you're still able
to get these lovely sustaining
notes out of the thing.
Feel free to sing
along if you want to.
Okay getting to the
last few points now.
Intonation is a critical
aspect of making guitars.
If you don't get this
right your musician's going
to throw the guitar
back at you and say,
"What did you make this
piece of rubbish for?"
This is another classic for
slavishly copying designs,
which you might get from perhaps
nowadays Chinese factories.
But, historically perhaps
Korean and then before
that Japanese factories just
simply grabbing a guitar
from the west, copying every
part of its design and trying
to sell that out to the public.
They didn't know why the
intonation was an issue.
They didn't know why we have
on this bridge here a
little slant on the saddle.
I'm not sure if that's
perceptual in that picture.
But, thicker strings
are far stiffer
than the thinner strings.
And on a guitar the thinner
string is at the bottom
and they progressively
get thicker as you go
up to the bass strings.
And so they all flex
a different amount.
The nice slinky thin strings
they can pretty much vibrate
along their ends
as they're fixed.
But, if you get a heavy bass
string and try and fix it
at the two ends it doesn't
actually vibrate along its
whole length.
It can't because of
the stiffness inherent
in the material the very,
very ends of the string
are actually held quite
stiffly there.
And progressively
that relaxes as you go
into the centre of the string.
So, there's dead
points in the string
that are actually what you would
think be actively vibrating,
they're not vibrating at all.
And as you progressively go
to thicker strings this
becomes more of a problem.
And so rather than slavishly
copying the designs that you see
on historic guitars you should
be measuring these things.
And so we start to slant the
saddle on the bridge here
by a very precise amount and
go even further than that
that you would carve the shape
of this piece of bone on there
to accommodate different
gages or styles of strings
so that they would
intonate correctly.
And that's quite important
that we get that right
that the guitar would intonate.
The way it's done it's
not rocket science.
You get a tuner out.
You play a note and you
play the octave of the note
and see if they're the same.
And the octave should
be the same
as the original fundamental note
and an easy way for you guys
to hear that, I guess, is
playing open chord down here
and then play the same
open chord up here.
It's very much in sync and in
harmony with those open strings.
We can hear that.
Once again, what can I say?
This guy has got the
right idea there.
So, he's got the intonation
right on that particular guitar.
And that's not done by ear.
I'm no-- I'm not trained
to hear tones by ear.
I do that with a strobe tuner.
And that's a big part of I
guess the dollars I've made
over the years is in
setting up peoples' guitars
from cheap copies and
turning them into something
that actually works musically.
So, that's a very
common thing to do.
Most importantly the bridge--
we're getting now to the final
aspects of all of these things.
This is just-- the importance
of this can't be understated.
It really is the thing
that connects the strings
to the whole guitar body
and so its height, weight,
type of wood, amount of flex
are very, very important
to the overall tone
of the guitar and how
that then interacts with
the rest of the guitar.
It is the most important brace
and luckily for us
we can see it.
It's on the outside.
The best place to put
the bridge is right
in the centre of the guitar.
If you put it in the
centre you're going
to get good monopole action.
You're going to get the
thing going in and out.
And we can illustrate that with
a little windup toy box here.
Does anyone have a
birthday today at all
or had one this week at all?
Alright I've just got
a little song for you.
This goes out to you.
[ Music ]
Okay so that's the
mechanism itself.
It doesn't make any--
much sound at all.
I put it inside this box.
It makes a little
bit more sound.
But, what about if we stuck
it on the bridge of a guitar
that has its back
supported up and we stuck it
where the bridge location was?
Wow, fantastic.
[ Music ]
Hip, hip. We could
also try sticking this
on the edge of the guitar.
Why don't I stick
the bridge over here?
Wow this guy's got a
nice resonant guitar.
It's supposed to be
quite tinny and trebly.
Nowhere probably as resonant
as we'd find in the--
right in the centre
here in the bridge,
so it's an obvious
place to put the bridge.
And its placement is
quite critical to getting
that monopole mode
going on a guitar.
Here's a few guitars I've made
and one we just played
earlier the short scale guitar,
look where I've put the bridge.
And I told you there
would be something
about why the bass frequency
of this particular
guitar is not great.
This instrument was
constrained by its player
who had tiny little hands.
And they have to be able to
put their hands around here
and actually physically
be able to hold it.
And I can't stretch the
neck right out there,
which would then pull the
bridge into the correct position
because then the neck would
fall forward on the thing.
So, the whole design
of this guitar I knew
from the outset wasn't going to
be the most efficient design,
but it was something
that they could
at least play and
get started on.
If only she would.
The next one along-- I'm
not sure if we brought that.
Yeah we did.
The next one along was the
next daughter's guitar.
The first one of course,
complains that hers was smaller.
This one's bigger and
better apparently.
And the bridge placement
here is wrong again.
It's completely wrong to get
the best bass sound out of that.
It's not bad, but it's
not very resonant compared
to the larger body guitars
with the bridge in the centre.
This again was constrained
by the player.
If I stretch that neck
out by another two frets then
the guitar would fall forward
and she's not strong enough
to play a guitar like that.
But, I do have-- every guitar
for me is a point on the graph.
And we can see the one on
the right hand side was made
for a friend last
year for his daughter.
I very quickly realised it
wasn't for his daughter at all
because he had asked
for a full width neck,
which she wouldn't
be able to play.
It was for him.
So, it was a great excuse to get
another guitar under the radar
of his wife and built pretty
much to what he wanted.
So, this then allowed me to
do another point on the graph.
What about if I stretch
this by another two frets
and had the body join here,
exactly the same body shape.
And exactly the same body shape
is our friend Bob Coleman's
guitar is made as.
And this is how Bob's
guitar is going to be made.
So, his bridge is going
to be put in the centre
by pulling this whole
scale up a little bit
and stretching the neck
out of the body and then
that will place the bridge where
it should be for great sound.
Ah I think it's that one.
The bridge and saddle
is how the loading
of the strings gets dumped
on down to the soundboard.
So, I can't really
quantify what you do here.
It's a feel that I've got.
And it's a feel that I've
got overt making a number
of instruments, which
really is the way you start
to get a handle on how these
parameters affect the tone
of the guitar.
And you can tell if you
had a really high saddle.
Some people do this.
They put a really
high saddle on.
It dumps a lot of force on the
guitar and makes it very loud
for usually a short
period of time.
And over the months the strain
on that will eventually bow
and buckle the soundboard down.
Another trick and a
trick that the people
who slavishly copy guitars
onto where of and don't put
on their guitars is there
is a little relief slot cut
so that the string here can
come down without having
that saddle up too high.
And you should cut these little
relief slots in very accurately
and specifically to what
you've known works before.
And that's another way of
dumping a little bit more forced
down onto the guitar top without
having the bridge and saddle
to high down or to
high up, sorry.
Finally, the finish is
just about the finish.
When you put all these
together you then spray it
to protect the wood
against knocks,
beer or whatever you might be
getting onto the instrument.
But, also you're protecting it
against rapid moisture changes.
That's the worst thing
you could ever do wood.
How stressful was I bringing
this collection over here today?
It couldn't stay in my car
at all so it had to go back
into the office and back
out into the car again.
Modern lacquers have got to be
applied as thin as possible.
Factory guitars like durable
instruments then spray a great
big thick coating right over
the top of their instruments
and kill all of that
wonderful tone off.
They're quite happy to do that.
The old traditional shellacs
and French polish has an
extraordinarily thin finish
and that is the best one
you could ever possibly use.
I don't use it because
it basically is very,
very-- it's easy to wear.
It-- alcohol will dissolve it.
Not that you ever do spill
alcohol on these things.
But, alcohol will
dissolve and even heat
on that thing will
affect the shellac
so really it's not a
great modern finish.
And so my lacquers I
use are as thin as I can
to still get a nice
polish onto the guitar.
Okay thank you very much.
I hope you enjoyed that.
Sorry about the gratuitous
advertising.
But, I do have cards up here
and you're welcome later to come
and look at the instruments.
Could I ask please if you could
just ask me first before you
play any of these things?
A lot of these aren't--
haven't been sold yet
and some are belonging
to people.
So, if you could respect
that that would be great.
[ Applause ]
>> You do have time to answer--
>> Well, do you have time?
Absolutely I do.
>> About five minutes.
>> Make it snappy.
Yes?
>> What adhesive do you use?
>> What adhesive?
I use aliphatic resin and also
some of the joints actually,
on the guitar for future and I
look ahead, need to be repaired.
And so, I'll use
animal hide glue,
the old traditional animal hide.
And that's a very,
very strong glue.
>> [inaudible]
>> Yeah that's right, yeah.
And both those glues are
stronger than the wood itself.
Yep?
>> I was just interested in the
effect of age on instruments.
I know there's been
a great debate
about whether it's true or not.
I just wanted your take on that.
>> Ah well, it's-- it is true.
There's a product came out
this year in fact that sits
over your strings and has an
oscillating electromagnetic
field in it.
So, when you're not playing
your guitar it sits there
and sort of plays it for you.
And it's well known that that
will break in a new guitar.
So, that's a product
specifically aimed at luthiers
to get a guitar to break in
and so old guitars
absolutely have a go.
It's really hard
to get these things
to be 80 years old right now.
So, the best thing is to
sell them and play the hell
out of the things be
the best way to do that.
Yep?
>> [inaudible] of
resonating guitars.
>> That's right.
>> So, how-- what is that--
what's that promotion,
the monopole?
>> No. I thought an idea to
promote something with it.
This was actually my
very first guitar I made.
And I guess the reason I
made that was all I had
to do was get the
bridge location
in the right spot
for the scale length.
There's no-- the
frets are in there,
but they're not actually played
because this is played
with a slide.
And so I guess I was
thinking this might illustrate
that you can use other
things other than wood
as a vibrating device as well.
So, this uses a very thin
aluminium diaphragm underneath
this heavy chrome cover here.
Yep? Sorry I didn't
play that one earlier.
Yeah?
>> Have you really tried
making necks with frets,
different spacing like
for different frequencies?
>> Ah--
>> Experimented, no?
>> Ah that's-- yeah I did.
That's what I did with this guy.
So, you can pretty much choose
any frequency you want to out
of this guy because
we're using a slide.
So, we can use halftones,
quarter tones
and all that style of thing.
With fretting no we don't.
Usually we fret an
instrument so that it's
in the diatonic Western
scale so not as yet.
>> I have a naive question.
>> Naive question.
I like them.
>> I suppose wood is
central to the guitar itself.
What about electric guitars?
Do you need wood?
>> Yeah indeed, an
electric guitar,
typically three pieces of wood.
Some people might correct me.
There might be four
if they're capped
with a particular
exotic species.
They have the body wood, the
neck wood and then the wood
that would clamp on top of the
neck would be the fret board.
So, they have very minimum wood.
But yeah, the type of wood
in the body does definitely
change the character
of the guitar.
>> I've seen electric
guitars made from plastics.
>> You can as well, but
they have a particular tone
and quite a nasally
tone to them.
Whereas the nice woods are
older or even the basswood
that I talked about earlier
make really good guitar bodies
as well.
And mahogany's a nice one too.
So, it's the same
basic principles apply.
We're talking about
the dark side here
of electric guitar making.
So, I have forayed
into the dark side,
but only as personal
instruments for myself.
>> Anymore, yeah?
>> Ming.
>> This is the last question.
>> What's the use
in the cutaway?
Is that just an aesthetic
thing or is that--
>> No. The thing about playing
in the modern styles
is people want
to have access to
the frets up here.
Why would you bother
fretting up there
if you can't get your
little mitts up into there?
And so the idea being
you put a cutaway there
and obviously you can see
that would facilitate your hand
going right up to the top there.
>> Does that compromise
the acoustics by?
>> This part of the guitar
top if we have a bit of a tap
around then we go
down to the bridge.
You can see this is
quite an inactive spot.
But, what it does do is
it reduces the air volume
and the air volume usually
around this area
here is responsible
for that helm hold resonation.
So, it doesn't really
affect it that much,
but I notice it does
have a slight effect.
But, certainly not
enough to say I don't want
to have a cutaway
because of that.
It's really more
aesthetic I guess and access
to these frets up here.
Yep.
>> Okay thank you
all for turning out.
>> [Inaudible]
>> Yep.
[ Applause ]
[ Music ]
[ Silence ]
