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>> 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.
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