Bridge design for lyra

[phaedon]

Hi all,

 

I'm more or less a beginner in woodworking & making instruments, and am seeking to specialize in making the pear-shaped lyra/kemençe of Istanbul (http://lyrafiddle.com/)

 

As an experienced player, I'm also interested in discovering how to make my existing instruments sound better, and I'm thinking about investing a chunk of time in figuring out the bridge.

 

Since the instrument is not quite as standardized as the violin family, there seem to be many more variables to explore here, including:

- type of wood

- height of bridge

- curvature of top

- tapering from base to top

- thickness/length of arm (the bit that extends over the treble soundhole and sits directly on the soundpost)

- size of foot (the single piece that sits on the soundboard)

- number of holes & shape of holes

etc.

 

Does it makes sense to use any engineering design tools (i.e. modal analysis using FEM) to analyze the geometric variables, and is this even possible given the strong anisotropic properties of wood? Does anyone here have experience or words of advice in case I'm embarking on a futile mission?

 

 

[Marty Kasprzyk]

Interesting instrument.  Where is the typical position of the sound post?

 

I think you identified most of the bridge variables.  The bridge height (h) and curvature is likely dependent upon the width of the body at the point of string bowing in order to get bow clearance during playing. It might be a good idea to just copy existing ones and forget about those two variables at the start.

 

It looks like the outer width (w) at the bridge feet is about the same as the width of the soundboard between the D holes (the "D" originated from Dah like in slang Dah holes which is a better descriptor than the English "The holes").  I think this might be an important variable because the bridge height/width ratio  (h/w) affects the downward force from the rocking bridge as the strings are bowed. 

 

Making the bridge width narrower would probably make the sound louder which is good but if too narrow you might get a wolf note. I would keep this as a variable to play with but I wouldn't bother much with changing the foot length or width other than making sure they fit the top plate well.

 

I think the most important variables will be the tapering from the base to the top which determines how top heavy the bridge will be.  The overall thickness and wood density will determine the bridge weight which I think is important.  You can use thick low density wood  or thin high density wood to get the same weight so the wood choice is important.  I've made viola bridges from balsa, paulownia, spruce, maple, and rosewood and they all seem to behave similarly if they have the same weight.  My light bridges were brighter sounding and louder.  Heavy ones were muted and smoother sounding so your personal taste dictates.

 

I'm not sure about effect of the wood's damping.  It would be interesting to find out what wood was used in old lyras.   I'm guessing that fairly dense wood was used and that the total weight was kept down by all the cut outs and the narrow top wings.

 

I don't know what a "good" lyra sounds like but I suspect that, like a violin, the top plate's thickness determines much of the lyra's sound character and that the bridge has to be chosen for that top:  thick tops might need different bridges than thin tops.

 

Anyway it looks like a lot of fun ahead.

[Will L]

I doubt there is a sound post in this type of instrument.  Is there?

 

Some wonderful examples of the sound on YouTube.  Type in "lyra instrumental music."  

[phaedon]

Thanks, Marty, for the thoughtful response. There is indeed a soundpost, and on modern instruments this tends to have the same diameter as a violin soundpost. However, the difference is that the "arm" of the bridge sits directly on the soundpost, i.e. the soundpost is visible to the player. (See http://lyrafiddle.com/antiques/aziz-mahmut-1904/ for a typical photo). So there is only one foot that sits on the soundboard, and it is quite a bit narrower than the space that separates the D-holes (although it typically lines up with the bass edge of that space).

 

The question about what defines a "good" lyra sound is also interesting as the aesthetics have evolved over the 20th century. We have a great many recordings from 1905-1930 that have a lighter, more nimble and focused sound; in Turkey today the tendency has been towards a heavier, breathier tone. The playing style has changed too.

Here's an example from ~1915:  

and a contemporary one: http://www.youtube.com/watch?v=8J5Z6sVZkyA

 

The carved bodies of old lyras were typically made of either mulberry or walnut, while the (arched) soundboards were either Cedar of Lebanon or Mediterranean cypress. I'm not sure what was used for a typical bridge; I imagine they might have used the same source of hardwood as for the body.

[DMartin]

Ha.

 

Love that nutless playing over the peghead.

 

Great concept.