Differences between fractional viola and 4/4 violin strings

[Theghostis]

Are there any key differences between the A,D,G strings intended for a 14" viola and 4/4 violin strings? I have read some older threads about viola strings and finding the right combination for particular instruments, and have seen some potentially good suggestions for short scale viola strings.

I am asking because my 14" viola is strung with violin A,D, G strings and a regular viola C. The A is a violin Jargar. the A,D,G are violin Warchal Amber. The C is a viola Warchal Amber (the shorter of the two Warchal viola sizes). I feel like my viola sounds a bit harsh which may be just a factor of its small size, its make and my playing ability.

Would short scale viola strings have any benefits over violin strings? The vibrating string length of my viola is 33.9cm with the way that the bridge is currently positioned. I only rarely get out the viola to attempt playing through some movements of Bach Cello Suites and that probably won't change any time soon since I'm currently trying to improve enough on the violin to play in amateur groups once the pandemic subsides.

 

[Marty Kasprzyk]

This is an interesting problem--skip to the bottom of this mess for a quick answer.  I hope others "tune in".

The string's  frequency f is proportional to the square root of the string's tension T divided by its mass per unit length u and inversely proportional to 2 times the string length L:

f = (1/2L)(T/u)^0.5

which can be rearranged to give:

T = 4uf^2L^2

If we keep use the same string u and keep the same tuning frequency f then it can be shown that a longer string length Ll needs to have a higher string tension  Tl compared to the original short string length Ls and its tension Ts.

The ratio of their tensions is proportion to the ratio of their lengths squared:

Tl/Ts = (Ll/Ls)^2

This can be rearranged again to show the tension Tl for the longer string length Ls:

Tl= Ts(Ll/Ls)^2

For example your  Warchal Amber A violin string has a tension of 54.25 newtons at a designed short violin playing length of 326mm.  Your viola has a longer string length of 339mm so your viola's A string tension Tl is:

Tl= 54.25 (339/326)^2 =  54.25(1.04)^2 = 54.25(1.08) = 58.7newtons

This tension is really high and is much higher than even high tension violin strings use which may contribute to why your small 14 inch viola sounds and played the way it does. 

 

 

So if you want to use A, D, G violin strings I suggest you use the lightest tension violin strings you can find (not "medium" or "heavy".) for example D'Addario Zyex  4/4L light tension violin strings.

On the other hand for your viola's C string then the opposite problem occurs. The string tension for your really small viola might be too low.  Then you might want to use a fractional or small size viola C string with as high a tension as you can find.

 

 

 

[nathan slobodkin]

Just bringing this up to the top again. Definitely an interesting question and I would like to hear from some of the other engineers if Marty's conclusions are correct. Also from any of the violin makers who have an understanding of the science ( which I don't) as to whether one could diagnose tone issues of instruments by trying different string tensions.

[Marty Kasprzyk]

On 3/29/2021 at 6:16 PM, Theghostis said:

Are there any key differences between the A,D,G strings intended for a 14" viola and 4/4 violin strings? I have read some older threads about viola strings and finding the right combination for particular instruments, and have seen some potentially good suggestions for short scale viola strings.

I am asking because my 14" viola is strung with violin A,D, G strings and a regular viola C. The A is a violin Jargar. the A,D,G are violin Warchal Amber. The C is a viola Warchal Amber (the shorter of the two Warchal viola sizes). I feel like my viola sounds a bit harsh which may be just a factor of its small size, its make and my playing ability.

Would short scale viola strings have any benefits over violin strings? The vibrating string length of my viola is 33.9cm with the way that the bridge is currently positioned. I only rarely get out the viola to attempt playing through some movements of Bach Cello Suites and that probably won't change any time soon since I'm currently trying to improve enough on the violin to play in amateur groups once the pandemic subsides.

 

It also might help to experiment by putting a small weights on the top part of your bridge to filter out some of the high frequencies which should  reduce your viola's harshness.  If you go to Joseph Curtin's web site you can see how he screws on small weights to his ultra-light viola bridges to mellow out their sound.

I just stick on tiny globs of Orvis heavy metal sink putty which is tungsten metal powder mixed with something sticky.  Fishermen use it to weigh down their lures so they sink further down in the water.  The same thing happens with violas.

 

[Theghostis]

Thank you to those of you who responded to my post. I was locked out of the site for a full day because of a password mix up so wasn’t able to reply when I intended. I was hoping to hear a little bit about string tension and why violin strings may or may not be ideal for my tiny viola. It’s interesting to hear more about the specific string tension.

I wonder if the higher tension has anything to do with why the core is exposed between the winding on the D string near the bridge. It sounds like it would be worth trying some real fractional viola strings sometime to see if the work better than the current mix.
 

[Hierony]

As an amateur cellist, a physicist, and wannabe luthier I'd say Marty's analysis is a good first approximation. Caveat to his tension calculation: only works for an identical string (ie, doesn't work if the linear densities of the long & short strings are different); great for seeing how the tension might change.

But there's more to strings then just tension. A quick survey of Warchal's and Thomastik-Infeld websites shows some suspicious trends. Tension doesn't change with different winding materials (density of Cr is 7.14 g/cm3, Al is 2.7 g/cm3). The difference in tension between string products is negligible (often <1%) compared to different gauges within a product (up to 20%). So my guess is that a different property is at play, only somewhat related to tension--elasticity, perhaps? Either that or some of the data is not accurate...

There's a lot that'd go into making a more complete recommendation. For instance, is it actually a 14" viola or a restrung violin? How old/used are the strings? What's the quality of the instrument? What's the setup like--bridge position/quality/cut, soundpost position/tension/fit, fine tuner weight/number, tailpiece size/weight/tailcord hole setup, tailcord material/length, etc? These details are much easier to see in person at a glance than describe via text.

For a cellist strings are more expensive so simple/easy setup changes can be more cost effective. For violins/violas the opposite seems more true. Ie, throw a little money at a new set of strings and see what happens? If that doesn't do anything go to a good luthier.

[Theghostis]

Now I’m wishing I had started a thread about my violin and not my viola, as these questions about setup as well as information on string tension are quite interesting. I think some people on this forum would have some great thoughts as to what ails my violin.

 

@Hierony now I’m going to be tempted to make changes to the setup of my viola, however that could lead to more problems due to amateur setup attempt failures. I probably couldn’t really describe a lot of elements of the setup in writing but I notice some interesting things when I look at it. 
 

The viola is a Carlo Lamberti Tertis model. It looks like the bridge used to be about 3mm closer to the tailpiece based on an imprint in the varnish. It has four screw in type fine tuners, three of which appear to be titanium. The string after length is only about 4.4cm. The bridge is about 3.8cm tall however I was having difficulty figuring out exactly how to measure it, so that’s only an estimate. 
 

I made an error regarding the A string in my original post. It’s a Jargar, not a Warchal Amber. I also notice that the bridge protector may be a little too far over the bridge.