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Re: 6 string griffrett: next project

Posted: Fri Jan 26, 2018 8:13 am
by kenbloom
The math here is simple. If you keep the length and tension there same, you simply double or halve the diameter to get an octave lower or higher. For instance, if you have a string that is .040" in diameter playing a particular pitch, say A, then you would have to go to a .020" to get string that would sound an octave higher. You balance this with the particular instrument. If you keep the diameter the same, you have to double the length to drop an octave. For yoiu high E, I would say that a .009" would be about the best choice if it will work.
On most guitars, the E that you are going for would be about 12 1/2" to 12 3/4" long. On my guitar I use a .012" for that string. Dropping the diameter to .009" should give you enough tension room to get up to the required note. This is easy enough to try on one of your zithers before you go abroad. Just go to any music store or guitar shop and get a .009", put it on and see if you can get it up to a high E. If you need more info about all of this, just let me know.

Ken Bloom
http://www.boweddulcimer.org

Re: 6 string griffrett: next project

Posted: Fri Jan 26, 2018 8:41 am
by Rudy Mueller
Thanks Ken,

If halving the diameter is an octave, and I only need to go up a fifth, there should be a couple of choices of diameters, maintaining the tension.

A simple rig may be constructed to get a rough estimate of string tension on the griff strings. The 6 stringer in Essenheim may have a shorter griffbrett. More later

Rudi

Re: 6 string griffrett: next project

Posted: Fri Jan 26, 2018 10:28 pm
by kenbloom
Hi Rudi,

The actual pounds of tension isn't really as important as the feel. I prefer a solid phosphor bronze D string and I know the actual tension is lower than the adjacent steel strings. Even tension is nice but may not achieve the best sound or feel. You can get thinner strings than a .009" but in may experience any string thinner than the .009" will have a tendency to break far more often. Again, it's achieving a balance between the scientific ideals and the musical goals yoiu're after. Good luck with the project and do let us all know how it works out.

Ken Bloom
http://www.boweddulcimer.org

Re: 6 string griffrett: next project

Posted: Sat Jan 27, 2018 11:37 am
by Rudy Mueller
A simple bench was made to measure string tension. The available scale was a baggage scale.

The tension on the a string was found to be 12 kg when tuned to a 440 a. Does this sound about right?

Personal responsibility calls. Will finish the remainder of the griff tensions later, probably Monday. I will include photo if I can get it off of the I-phone. Will send it if you send e-address to RMUELLERMKE@GMAIL.COM.

rudi

Re: 6 string griffrett: next project

Posted: Sat Jan 27, 2018 2:05 pm
by Rudy Mueller
Couldn't wait until Monday. The tensions measured here on the grifbrett strings are

a 12.0 Kg

d 10.8 Kg (bronze)

g 12.0 Kg

c 9.2 Kg

These measurements are to the nearest 0.2 Kg; for example, 12.0 Kg means not 11.8 or 12.2, but could be 11.9 or 12.1 Kg. I'm not sure of the pedigree of the strings, but will check. Hopefully I'll be able to fine an e string which will require 10 to 12 Kg to come in tune.

Rudi

Re: 6 string griffrett: next project

Posted: Sat Jan 27, 2018 6:38 pm
by Rudy Mueller
Please, does anyone have, have access or reference to, a table of zither string tensions?

I'd really like to know if I'm even in the ball park.

The Förg will be getting new strings soon.

Would it be of interest for the community to measure the tensions on the top side? Realizing that these are crude measurements, it would be just a little more effort at the time of new string installation. No problems once the bench is set up.

rudi

Re: 6 string griffrett: next project

Posted: Tue Jan 30, 2018 1:49 pm
by Rudy Mueller
String length on 6 string Griffrett

As luck would have it, the string length (zero fret to bridge wire) on the 6 string zither is 39.0 cm, as contrasted to 43.5 on the Förg. That should simplify and expand string choices.

Rudi

Re: 6 string griffrett: next project

Posted: Sat Feb 10, 2018 9:27 am
by Rudy Mueller
Titanium wire, 0.5 mm diameter, 99.9% pure, failed at a load of 7 kg when tested on the Förg as an "a" string. This was "pure" titanium;
other alloys are available. Just prior to failure, the Ti string was about in tune with "f" on the "d" griff string.

Next attempt will be E4 (?) steel guitar strings, in the range 0.25 to 0.36 mm, again testing these on the Förg as an "a" string. Zither Sunday tomorrow (February 11) and arrangements will be made to obtain these guitar strings.

A new set of zither accompaniment and bass strings is on order for the Förg, and will be tested under load during installation.

Rudi