Official Luthiers Forum!

Thought you guys might get a kick out of this. At the 10-string Festival this past weekend, I had the pleasure of meeting Michele Ramo and his wife Heidi Hepler. Michele (pronounced Me-KAY-lay) is an 8-string jazz guitarist, and his wife, Heidi, is a singer (got a nice set of pipes, too). A classically trained violinist and a self-taught jazz guitarist, Michele is originally from Sicily. He and Heidi now make their home in Queens, NY. You might want to click around at their site -- they've got several sound clips available for sampling.

Michele and Heidi have posted a selection of photos from the festival, which can be viewed here. There's even one of him and me

At the concert, Michele played a guitar that he designed and developed, built by NY-based luthier Rich DiCarlos. Check out the 8-string guitar website, and have a look around. Lots of photos of the different models that Rich DiCarlo is building and some sound clips too. Here's a pic I took of Michele Saturday night:



Now there are several remarkable things about this guitar. Probably the most remarkable is the string layout and fingerboard design. The bottom two strings are tuned D (8th) and A (7th). The D is tuned TWO octaves below the open D string, or one whole step below the open E on a bass. The A is tuned one octave below the open 5th string. If you look closely at the above photo, you'll note that fingerboard beneath the bottom two strings is fretless.

Michele is an exceptionally talented player. His arrangements incorporate bass lines that he plays on the bottom two strings, and dang if the sound doesn't sound just like an upright bass. He tunes the two bass strings a 5th apart because it makes it a very simple operation to do a I-V bass line accompaniment to his rhythms and solos.

The guitar uses the RMC piezo pickup system for the strings (same pickups used on the Godin Multi-AC), that are divided into two separate systems, one for the upper six strings and one for the bottom two. This allows him to run the guitar section through an acoustic guitar amp and the bass section through a bass amp. The RMC transducers will support the Roland GR-33 guitar synthesizer, although the necessary interface module hasn't been added to the guitar yet. But Michele has plans to do so.

He owns four of the DiCarlos, each one different from the others.

Oh, almost forgot. Yes, this is a nylong string guitar. The low D is like 0.080" or something. He has to special order it.

Best,

MichaelMichael McBroom38908.6649189815

_________________
Live to Play, Play to Live

Michael, That is very cool. Are the low d and low a strings attached to a tailpiece or is that a second bridge?

_________________
Joe Breault
Merrimack, NH
Perpetual novice

Hi Joe,

I should have explained that as well. The saddles are RMC transducers, located at the bridge with the others. The tailpiece that has been added is done to increase the overall string length. Something that can't be discerned from the photo is the fact that the upper two tuners on the headstock's bass side are used for the two bass strings, with the D getting the tuner closest to the tip of the headstock. Once again, this is done to maximize overall string length.

A lot of folks claim that the distance between the saddle and nut determine string tension. This is not the way I understand it to work, which comes from a rather dimly remembered physics class I had over a quarter century ago, and it isn't Michele's understanding of things either. The way I recall learning it, the longer the overall length of a string of a given cross-sectional diameter, the higher tension it will be at a given frequency. I guess in order to prove this once and for all whether or not this is true independent of nut and saddle distances, I will have to build a test jig and measure the results. Should be easy enough to do.

Best,

Michael

_________________
Live to Play, Play to Live

The string tension idea is a myth, I'm afraid. It doesn't matter what happens beyond the nut or the bridge, the tension of the string will be the same. A wiser man than I told me:

"There is no rationale in physics I know to say that adjusting the nut and saddle height or altering anything to do with the string outside of the area vibrating to produce your note (between saddle and nut or nut) should affect string tension.

The relationship between pitch, tension, length (between saddle and nut/fret) and string gauge/weight is given by:

      1     ;           ; T
f = --- x square-root ---
      2L   &nbs p;           µ

Here, f is the frequency of the note in Hertz, L is the scale length in metres, T is the tension in Newtons (divide by 9.81 to get tension in Kilograms), and µ is the mass per unit length of the string.

There is also a formula for describing how much deflection force is required - e.g. how tight or floppy a string feels. Again there is nothing in this that should be affected by saddle or nut height or string length outside of the part being played:

     4dT
t = ------
       L

t is the deflection force (the force needed to pull out the string), d is the deflection, T is the string tension and L is its scale length.

From the above equation you can see that longer strings need to be under higher tension in order not to feel floppy.

Cheers - hope that helps. But you'll still find many guitarists who like to believe other factors matter (e.g. I've heard it said that the longer nut to tuner distance on Fender bass strings affects the string tension which appears to have no basis in physics (and you can imagine - you can adjust the string on a strat and then use a locking nut which clamps the string at the nut, and then cut off the string behind the nut - would that change how the string feels? No!)."
LouisianaGrey38908.7328125

_________________
Pete
http://www.petewoodmanguitars.com

Sorry about the double posting, it won't seem to let me edit or delete the previous post and it's messed up the formula.
The string tension idea is a myth, I'm afraid. It doesn't matter what happens beyond the nut or the bridge, the tension of the string will be the same. A wiser man than I told me:

"There is no rationale in physics I know to say that adjusting the nut and saddle height or altering anything to do with the string outside of the area vibrating to produce your note (between saddle and nut or nut) should affect string tension.

The relationship between pitch, tension, length (between saddle and nut/fret) and string gauge/weight is given by:

     1    
f = ---
     2L
                      T
x square-root ---
                      µ

Here, f is the frequency of the note in Hertz, L is the scale length in metres, T is the tension in Newtons (divide by 9.81 to get tension in Kilograms), and µ is the mass per unit length of the string.

There is also a formula for describing how much deflection force is required - e.g. how tight or floppy a string feels. Again there is nothing in this that should be affected by saddle or nut height or string length outside of the part being played:

     4dT
t = ------
       L

t is the deflection force (the force needed to pull out the string), d is the deflection, T is the string tension and L is its scale length.

From the above equation you can see that longer strings need to be under higher tension in order not to feel floppy.

Cheers - hope that helps. But you'll still find many guitarists who like to believe other factors matter (e.g. I've heard it said that the longer nut to tuner distance on Fender bass strings affects the string tension which appears to have no basis in physics (and you can imagine - you can adjust the string on a strat and then use a locking nut which clamps the string at the nut, and then cut off the string behind the nut - would that change how the string feels? No!)."
LouisianaGrey38908.7424537037

_________________
Pete
http://www.petewoodmanguitars.com

Welp, you're right, LG. But being at times rather hard-headed, I had to prove it to myself.

The test rig consisted of a piece of plywood to which I attached a couple of tuners, and a tailpiece for anchoring the strings. I built a couple of nuts and a saddle out of mahogany, all the same height, with rounded over tops.

I attached one tuner close to the end of the plank and attached the other about 6" in from the end. The nuts were positioned together, about 3" in front of the tuner 6" in. Actually I didn't need separate nuts for the two strings, but I wanted to be able to make some comparisons later between this setup and having two strings of different scales tuned to the same pitch.

So I scrounged around and found a couple of unused Dean Markley 0.011" strings, and installed them on the rig.

To measure tension, I dug out a Zebco "De-Liar" from my fishing tackle box. It probably isn't all that accurate, but its precision in measurements between the two strings is most likely adequate.

I tried various ways of pulling on the strings, using the De-Liar, getting various results, mostly I suspect because the strings were still slipping on the tuners. Finally, I got the strings to where they would hold tune when being deflected 3/4".

I chose 3/4" out of convenience. The nuts and saddle are 3/4" high. I found my results were most repeatable when I pulled down on the strings until they just contacted the edge of the "fingerboard."

Speaking of results, yup. It's confirmed. Both strings measured exactly the same pull. In this case, it was about 3-3/4 lb.

Oh well. It seemed so plausible. I don't think I'll be breaking the news to Michele anytime soon, though. I don't need no Sicilian's PO'd at me right now.

Best,

Michael Michael McBroom38908.856712963

_________________
Live to Play, Play to Live

Don't beat yourself up too much, Michael. Before I got the answer from that kindly physicist I asked the folks at D'Addario and they said they didn't know.

_________________
Pete
http://www.petewoodmanguitars.com

Hey LG,

You know, there's more to the story, though. I didn't want to clog up the previous post with this stuff. So I'll post it separately.

I discovered that the string with the short length reached its elastic limit before the long string did, and that this occurred sooner, the shorter the scale was between nut and saddle. And what's more, once this elastic limit was being approached, the amount of tension required to deflect the short string became much higher than the amount of tensions needed to deflect the long string by the same amount.

This all has to do with a string's Young's modulus, I believe it's called, aka "stretch modulus," which is an indicator of how much stretch a material has before becoming permanently deformed, if I'm remembering this correctly.

Now, one thing I didn't take into account in the above measurements was the elevation in pitch that would be occuring at the higher tensions -- I really couldn't since I was pulling down at the midpoint of the scale with the De-Liar. But I'm sure that, even though the shorter scale started requiring more force for the same amount of displacement, the pitch by which the string was raised was probably a very large amount.

Still and all, I wonder about the practical effects of this. Take for example a Fender Strat with its 25-something inch scale and long headstock extension for the high E, and a Gibson LP with its 24.75" scale, and very short distance between the nut and tuner for its high E.

Obviously, the Gibson's high E will reach its elastic limit before the Fender's will when measuring amount of displacement vs. tension. So, even though the Fender's strings are at a slightly higher tension because of the greater scale, it seems to me that the Fender's treble strings will be more amenable to extreme bends than the Gibson's, simply because of the difference in overall string length between the two guitars.

I've always noticed a difference in feel between the strings on a Gibson and a Fender (I own a few of each), but I was never able to quite put my finger on what it was. For years, I thought it was the Fender's longer scale and the guitar's strings being at a slightly higher tension. But that didn't seem to quite jive with what I was feeling. It wasn't a tension difference so much as an elasticity difference. So perhaps the elasticity factor does have a bearing on the different feel between the two guitars.

Best,

Michael

_________________
Live to Play, Play to Live

The elasticity yields a softer feel because it is working over a longer length of string. You can see this effect with a cut rubber band. Pinch two places about an inch apart and pull it into tension. It reaches the elastic limit very quickly and this results in a "hard feeling". Now grab the ends of the band and pull it into tension with the same force you used on the short band. It still feels relatively soft because the stretch is being adsorbed by a longer length.