kevlar tail cord

August 5, 2013 at 08:17 PM · what's the consensus on replacing the nylon cord on the tail piece with kevlar cord. much ado about nothing? ... revolutionary improvement?

Replies (22)

August 5, 2013 at 08:56 PM ·

August 5, 2013 at 09:31 PM · ... and back in Baroque era - pure gut, for the best sound.

August 5, 2013 at 10:03 PM · i happen to have a suitable piece gut but i was taken with this:

August 6, 2013 at 01:30 AM · I have used them on some violins, but not all of mine have one. IMO it's like any other fitting. Works good on some and not on others - depends on the instrument.

August 6, 2013 at 02:01 AM · I put one on my viola.

Problem is, that at the same time as I did that I re-positioned the soundpost and put on a different set of strings. Sounded great afterwards. But it probably had more to do with the soundpost than the kevlar.

Anyhow, Im leaving it on there. Can't hurt.

August 6, 2013 at 03:01 AM ·

August 8, 2013 at 03:28 AM · DON'T.

Biggest waste of money. They stretch after you get them right, are too flexible imo, and...cheapen the sound quality to be honest. Ken Stein told a friend 80% of his days are cutting them off.

But they didn't work for me doesn't mean it won't for you. I think it's a waste and more frustrating than beneficial. I think it's a fad like those cutaway tailpieces. Again just my experience! Don't shout at me!!

August 8, 2013 at 02:26 PM · I put Bois d/Harmonie Kevlar tailcords on my 3 cellos and on 4 of my violins.

I would not have done that if I had not liked the tonal results on each instrument as I progressed through the lot.

Yes, the cords are overpriced. And installation is not easy. The cord does not stretch, but the knots "tighten" under tension so it is a good approach to tie the cord a bit short (perhaps 1/4" on a cello and less on a violin - in proportion to the cord thickness) so it will stretch to the desired length.

The string afterlength (distance from bridge to stop on tailpiece) may have a significant effect on the sound and response of some instruments (so does the "free length" of the tailcord from the end of the tailpiece to the peg. The 1/6 length ratio recommended for afterlength to the sounding string length is based on having the afterlengths resonate at a natural open-string vibrating frequency for a perfectly uniform string. Unfortunately, with the irregularities of modern strings (because of finish windings between bridge and tailpiece) you can perfectly tune only one string afterlength; I try for the D or G (on violin).

There are some new tailpiece designs that have different afterlengths for each string; I have not tried any of them, but there are certainly some good reports about lower-string resonance using them.

One more thing about the Nylon Saccony tailcords. Years ago when I was playing around with them and trying to save money (after Frank Passa's patent expired) I found that the off-brands tended to stretch - and keep on stretching after installation. I visited Frank (after he had retired, after his first stroke) and his family still had the Saccony tailcord production going in the large garage of their beautiful home in Santa Rosa.


August 8, 2013 at 03:22 PM · Anybody have experience with the steel tailguts?

Here is an article written for a cello site that describes the effects as they see it:

August 8, 2013 at 07:51 PM ·

August 9, 2013 at 04:45 PM · My experience has been that kevlar thins and concentrates the sound. This usually doesn't work on violins and a lot of new instruments, but can work wonders on something like an ancient cello that sounds fuzzy and diffuse, or on furry-sounding wide violas.

August 9, 2013 at 09:42 PM · I tried them for a few years, and ended up abandoning them, not so much for tonal reasons, but more for practical mechanical reasons.

For one thing, as Andrew Victor pointed out, while the cord itself may not stretch, the knot compresses, so they don't hold their length. And it's danged hard to adjust the length with any sense of accuracy. It's not like some others, where you can take two turns on a threaded screw, and know exactly how much difference that will make.

The real kicker for me was when I came across one of the Kevlar cords which had been cut halfway through by a sharp edge on a cello tailpiece. I'm all for good sound, but it might not be worth killing or maiming someone in the violin section for. ;-)

If someone puts threaded ends on a Kevlar tail adjuster, maybe I'll try it again.

August 10, 2013 at 03:01 PM · Since I work a lot with non-standard instrument sizes, finding any kind of modern tail cord that fits them all has been a frustration. I use Kevlar where this is the case, and I also use it a lot on cellos and basses.

It is amazingly strong, and has the benefit of being a material that does not stretch. Others have pointed out that the knot will compress and tighten initially, which can change the tailpiece position, but in this respect it's no different than the hundreds of gut tail cords I put on when I first started in this field. You get the knack of adjusting in advance. If not, you cut the cord off and tie another one on. It only takes a minute or two.

Kevlar is hard to cut cleanly, and some varieties will start unwinding. I dip them in a bit of liquid shellac, and when it's gummy I pat the strands together. This will hold them long enough to get them through the holes in the tailpiece. Once the ends are tied off, the unraveling stops. For a really clean appearance, a small snip of shrink tubing over the end looks excellent.

If the Kevlar gets cut by something on the tailpiece or the saddle, it's not the fault of the Kevlar. Those conditions would also cut nylon and true gut as well. I must also point out that nylon and gut are both famous for stretching. The little flowered ends of the gut get brittle and snap off, and the brass nuts on nylon tail cords can strip and send the tailpiece flying. This is never the case with Kevlar.

For larger instruments,there's a neat little trick that can be used, which I heard from Michael Darnton. You can twist the tailpiece and wind the Kevlar around itself so that it effectively becomes a single strand. If you continue, this allows you to change the position of the tailpiece without having to fit a new cord. You can often improve the sound in this way, and some commercial tailcord systems for big instruments are now available with a single cord.

The hypothesis is that a single cord allows the tailpiece to move more freely. I haven't yet figured out exactly what is taking place mechanically or acoustically, but my observations are that this works better with cellos and basses than it does with violins and violas.

August 10, 2013 at 05:35 PM · For what it's worth, I had several kevlars snap on cellos, cut through by the tailpiece. The kevlar was the same as used by one big-name shop, in fact. I found another variety that's much more durable, and that's working fine. The other stuff, I'm using that for shoelaces, etc, where it appears to be adequate, and I have lifetime supply!

I haven't had any stretching or adjustment problems--I think the knot you use has a lot to do with it, as well as the material; the old stuff was absolutely impossible to untie.

August 10, 2013 at 10:26 PM · michael - please explain "another variety?" i'm having trouble finding kevlar here in rural italy.

August 11, 2013 at 12:55 AM · The stuff I'm now using is for deep sea fishing, called "assist cord". It is densely braided, does not stretch, is relatively hard and does not compress much when you tie it into a knot. Also, it takes super glue well, which is handy for finishing the ends neatly.

I use the #70 size, and color it by dropping the whole roll into india ink for a while (I think leather dye is the same thing--it smells and acts the same). This is the only source I've found for it, and this brand is the only brand I've been able to find with the qualities I like:

August 11, 2013 at 08:10 AM · thank you michael!

August 11, 2013 at 12:24 PM · Robert, I agree that the nylon and gut tail adjusters can stretch badly, but when they do, I find them much easier to re-adjust in small accurate increments than the kevlar knotted ones.

On conventional, non-baroque tailpieces, the gut and nylon don't take a 90 degree bend over a sharp surface, so I have never found "cutting" or chaffing of this style of adjuster to be an issue on a conventional tailpiece. The kevlar adjuster however, by the nature of typical attachment, does take this bend. But I can see how a baroque tailpiece could be another matter when it comes to cutting or chafing the nylon and gut.

Twisting the Kevlar tail adjuster to change the length works well for that specific purpose, but in my experiments, produces an uncertain tonal outcome. It can sound better, but it can also sound worse.

I use the threaded stranded steel adjusters (such as the Wittner) quite a bit. They don't stretch, are about the easiest of all to adjust (it can often be done without even removing the tailpiece, just lowering the tension). I've never seen one fail for any reason, including going over a sharp tailpiece surface, and they can be twisted if one finds a tonal improvement from doing so.

August 13, 2013 at 08:55 PM · The core benefit of Kevlar is that it won't stretch. That said, if you are taking a violin all over the country, into different weather (e.g., humidity) environments, you will appreciate the Kevlar more than if you are playing at home or at school and your violin/viola doesn't go through major changes in weather.

August 14, 2013 at 05:01 AM · Interesting...made me rethink this.

My viola has a phenomenal tone, but it could be a little more cutting (I want people to hear it!)- would steel be good? I love the sound of celli that have them, but I'd be a little silly to say that the tailgut made the cello, not that the maker made it.

August 14, 2013 at 10:46 PM · I don't remember where I read this and my memory is sometimes faulty, but apparently Kevlar does not always age gracefully. I'm pretty sure that bullet proof vests are replaced every few years because they become less effective. It has also been said that Kevlar cord under constant tension for a long time can suddenly break. Maybe there are differences in suppliers, but I'm not tempted to find out.

September 10, 2014 at 06:19 PM · I just replaced a kevlar tailgut on one of my viola with a standard Wittner nylon. Mellowed out the tone noticeably, made it sound fuller and rounder.

Maybe for a cello, but so far my experiences on violin and viola are a no-go for the kevlar.

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