Double Bass Rib Bending

[Damon Rondeau]

Francois Denis is the man who a lot of us think unlocked the key to classical design.

His book is out, called "Traite de Lutherie"

And once again, showing that what is new is old. Pythagarus old.Before standardized measurement, designers thought not in numbers, but in comparative ratios. As in width of upper bout to width of lower bout, 5 to 4. Lots of ratios are used in the design of classical instruments, not just the golden ratio.

Common ratios like 3 to4, 1 to1, 2 to 3, 7 to 12, etc. If you read music, you recognize these. Very elegant.

Here's one of my violas.

A classically beautiful shape on that there viola... Lovely.

Hey, thanks for all this, Darren -- I'm much more pleased to follow someone who knows what they're doing with all this stuff. The instrument world must be rich with it...

Once I looked at half a dozen or so instruments I realized there were a number of ratios going on -- I'm sure a classical art or architecture historian, maybe math, would be able to fill in a lot of the blanks.

The picture of the Ross bass above shows there is adherence to the modular principle in all kinds of little ways: distance from scroll eye to the nut, 2 modules; length of tailpiece, 3 modules; distance between f-hole nicks, 2 modules...

There are deeper factors shaping why these instruments are so compelling to look at...

On another topic, Darren: I hope we can still be TB buddies after the Bombers get through with your Roughriders on Sunday.

 

[Darren Molnar]

Yeah,it's a very cool subject, And I can't reccomend that book enough if you're into that kind of thing. All those things you notice point to the beauty of the old instruments.That is, it was all intentional, towards a goal, following some strict rules. And it worked! Philosophy guides the methodology. Right down to the f-hole nicks.

I'll still be you're buddy,no worries. Man, that crowd is going to be epic! I wonder how many are going to bring their banjo's on the plane.

 

[Damon Rondeau]

The Denis book is in french?

 

[Darren Molnar]

No, there is an english version. Published by ADALFI press, which is the french violin bowmaking society, I think. Amatibooks.com sells it for sure. It's expensive,like all $#@ violin related books, so bet heavily this weekend.

 

[Matthew Tucker]

Its interesting and fun, and geometrical analysis is valuable, and we all do it.

But I share the view that you can do all that, and you can pretty much find a circle or circles to fit just about any curve and find some relationship to the other circles in the model, and call that significant.

You can then draw something from first principles, but whether or not the result is either aesthetically pleasing, or functional, is not a foregone conclusion.

I think its equally likely that in the past, models were copied just as they are today, by tracing outlines onto a piece of paper, then transferring that to a template, making a mould and then conforming the outline to the mould, then finishing the plates to the actual outline - whether or not the actual outline ends up being a faithful copy of the original. In the above process there are already five points at which deviations can occur!

And then there are those intentional adjustments made on the fly by the maker to satisfy a whim or hunch.

But of course, looking at the result, another person can often find another mathematical or geometric relation or ratio and infer that the construct is significant, whereas it probably isn't that much.

Circles and rulers are useful and simple tools for creating symmetrical shapes and the result is often pleasing to the eye, but I don't think one can say this is necessarily because of their use in the drafting process.

I happen to like FFs whose tabs are cut parallel and which point to the tip of the upper corner. But plenty of FFs aren't like this and still look nice. I haven't really found this much use, except that by noticing what i like, i can try to incorporate this into a drawing or a knife cut.

 

[Matthew Tucker]

In one book I read (actually, possibly was "Traite de Luthierie" a couple of years ago - was it out then??) the writer came up with two families of shapes, one in which the upper and lower bouts were composed from two circles (like the bob ross bass drawing) and another was composed from a single circle (like a Tarr or Cole shape I suppose). Interesting, but hard to know what it all means.

 

[Damon Rondeau]

At the end of the day for us modern folk it's just yakking and thinking about aesthetics -- what you like, what you don't like, the why of it. Personally, I'm interested in the historical side of it. For a modern maker it's probably a lot more important to get really good at keeping the tools dead sharp.

 

[Darren Molnar]

I miss the wink, matthew, but you look much more handsome than you used to.

Trace, transfer, trace, transfer, and on and on. It's hard to find proportions on basses because of this. But some DNA seems to remain. An example is the lower bout. draw a line perpendicular to the center line that touches the tops of the lower corner. Draw another at the bottom of the bottom rib. Half way between those lines is where you'll find the maximum width of the lower bouts. Look at Chris's plan. one to one ratio. That's where it is on all violin family instruments. you'll see it in the viola plan of mine as well. It's not supposed to have some kind of mystical meaning, it's just the rules of design and proportion from the olden olden days. When we forget these things and just start drawing curves all willy-nilly, then we end up with shapes like dreadnought guitars. (yuck)

 

[Matthew Tucker]

The wink will return when i shave off the mo' at end of Movember. here's one to go on with:

 

[Ken McKay]

Don, my apologies for attributing your two cents to Ken.

Matthew, the f-holes were not positioned with any great precision on what was never meant to be other than a first sketched outline.There seems to be a scarcity of advice available on the theory of f-hole placement and I have to acknowledge my indebtedness to Chuck Traeger's guidance for the probable way that I will tackle the placement calculations, always with the proviso that it will have to look ok to me from an aesthetic viewpoint.

Darren, the curves were created by establishing the extreme points of width and length as per the design sketch and then freehanding the curves to fit these points. It was important to me that there was a large measure of being guided by what I can only call my own aesthetic judgements

Design is facinating, for sure! I have done my share and am not particularly satisfied with any of my own designs. I would like to collaborate with someone who is interested to design a nice bass. The bass, being so varied, is a good instrument to get some nice curves yet retain some common features like diapason (top of body to ff nicks) and mensure.

There are really only a few critical things in designing a bass and the first and formost has to be string length. I think the standard now has got to be 1050 mm (41.34"). Sergio Scaramelli says that 600 is standard diapason and that ratio of the neck lenght to diapason should be preserved. The standard neck length would then be 430 mm taking into account that the angle of the neck would add 20mm to the length. 1050 = 430:600 plus 20.

So this tells you where to put your ff nicks. Down 600mm from the top of the front. And if you want to make it 650 for example then your string length needs to grow and in proper proportion, the neck lenght.

The other important factor in ff placement is where the bridge feet will sit. Ideally the bar will run under the bass foot and the upper eye needs to be out of its way.

 

[chris clay]

It is really fascinating to try to analyse the various factors that combine to allow us as individuals to recognise that which is harmonious to each of us individually...because I do believe that this response arises from deep within our essential humanity - this is not to say that the classical design proportions and ratios are not relevant, but that I believe they came into existence to record the harmony rather than create it.
I need to trust my own sense of what pleases me with the connections between the various surface planes and edges...impossible to set down as ratios at this stage perhaps but I'm fairly certain that there will be strong and visibly measureable geometric congruencies(?) in the finished instument .
Interestingly though, there are marked proportional similarities between my evolving bass and the very pleasing Bob Ross bass in Damon's post.

 

[chris clay]

Thanks Ken for reminding me that in all the analysing of the aesthetics of these beautiful instruments they have to work as efficient sound producers. My hope is that these aims are inherently compatible

 

[Darren Molnar]

You're right on Chris, efficient sound producers.You're last two posts have brought me back down to earth. Thanks. In the end, they have to play, and look pleasing. I think I sound like a crazy man when I talk design. I should add it to my list of think twice, speak once subjects. Politics, Religion, and instrument design.

Ken, it's interesting to hear you mention diaspason and ratios when you refer to basses, I wasn't sure bass makers were thinking about that. I was under the impression that it was string length, combined with figureing out the d- neck, eb-neck thing.

 

[Damon Rondeau]

I think it's a good thing that bass design hasn't settled into more-or-less fixed concepts such as one sees in violins. There's room for variety and experimentation and I like that. The classic designs say something (to me, anyway) deep and timeless about harmony and proportionality and the human sense of those things. I find a lot of the newer ergonomic designs (not just in basses, in all instruments) beautiful in a similar way -- they express human intelligence (about the body, about health) and love of music in a different way.

 

[arnoldschnitzer]

My personal belief is that the bridge belongs in the middle of the bass body, measured top-to-bottom. At the recent ISB I discovered that the fine French luthier Jean Auray shares the same belief. I am also of the opinion that f-hole area is extremely important, as is placement.

 

[Darren Molnar]

Arnold, i've been admireing you're web site or a long time, You're instrumens are beautiful.

When you design a bass, How do you start. For example, start with string length, decide on d or eb neck, place bridge, then place body around those measures? Are you using a standard diaspason and or neck/bridge ratio?

 

[Matthew Tucker]

Are you using a standard diapason and or neck/bridge ratio?

Diapaison means, literally, scale length.
I might be missing something, but isn't that the same thing? If you settle on a 41.5" string length and a d neck, your bridge/neck length is pretty much determined by that, unless you want an exceptionally long or short neck heel.

Arnold, I have found the "halfway" point for bridge placement can vary depending on where you measure it. If you need to bisect the vibrating plate, then I guess you must measure inside the blocks. If it's an aesthetic concern, then outside the blocks will do. But they're not necessarily the same position, expecially if you have a bass with sloping shoulders.

 

[Darren Molnar]

I might be wrong with the terminology.I am using it the same as Ken is, so there are two of us, at least. I thought diaspason refers to the distance from the bridge placement, to the edge of the plate. So the ratio I was asking about is the distance I just mentioned, compared to the neck length, that is, the distance from the plate edge to the bottom of the nut. in violins it is 3 parts to two parts. In violas, the same ratio, in cellos, 11 to 7. In Basses?,,,,,? It seems like a bit of a hole in bass design. But it may serve the purpose of placing the importance of ratio at the D-Eb area. A way of allowing both.

 

[Matthew Tucker]

but Ken is using "diapason" to mean top of body to ff nicks - that's a different thing to what you are talking about, top of plate to nut? Or am I getting mixed up here?

As far as I know, "Diapaison" is a pretty standard musical term meaning "scale" whether this related to length of organ pipes or the vibrating string. It can be used in a variety of ways I guess, in the end, its the same thing I think!

A 600mm "plate to nicks" measurement will probably give a standard string length of 41.75". Or a string length of 41.75" will mean, probably, a 600mm "plate to nicks" distance. Just another way of saying the same thing.

I like to use the bottom of the NECK mortise, where the overstand is measured, to be close to F on the D string. That's a useful visual reference point. It determines how deep the neck root will be.

 

[arnoldschnitzer]

Arnold, i've been admireing you're web site or a long time, You're instrumens are beautiful.

When you design a bass, How do you start. For example, start with string length, decide on d or eb neck, place bridge, then place body around those measures? Are you using a standard diaspason and or neck/bridge ratio?

Hi Darren; thanks for the nice words. I'm afraid there is absolutely nothing standard about bass design. You have crossed over to the dark side...

I generally start out with the body shape, working in to the design the placement of the f-holes, bridge, etc. There are certain numbers I like which seem to dependably result in good tone and playability. I also work in a D neck, and lay things out so the heel will be large enough to be strong, but not so large as to be bulbous.