Kenny Hill's new performance intonation "wiggly" fretting

Construction and repair of Classical Guitar and related instruments
amezcua
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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by amezcua » Fri Feb 09, 2018 9:44 am

So--Keep the door closed --and shout at anyone who wants to open it ? Very hard to argue with that .
But the Buzz Fieten is very good if you want to stay in ET. Strangely , it improves the whole guitar sound . But then others would disagree , mainly because they had not tried it . It`s a good system .
Last edited by amezcua on Fri Feb 09, 2018 9:18 pm, edited 1 time in total.

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petermc61
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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by petermc61 » Fri Feb 09, 2018 10:06 am

Sorry for being cynical, but....

The saddle and but are not compensated AT ALL. Why not do a string by string saddle and nut compensation which would also give exceptional results without the dinky frets?

Secondly, why claim “perfect intonation” when that is clearly impossible for a guitar.

Looks like more marketing hype than useful development.

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by amezcua » Fri Feb 09, 2018 8:57 pm

I can`t see the saddle in the photo .The octave fret is suspiciously straight but that`s not a bad thing . There is a whole variety of ways to do this . Dinky frets are not a problem in a practical way . Compensation ,which some people struggle to accept is a by product of the mathematical divisions for ET . It`s been around so long we forget the drawbacks , apart from never ending mentioning it . Perfect intonation can take many different forms. What is the perfect car? Is yours the same as mine ? You want perfect thirds .He wants perfect fifths .It`s what you choose . There are natural reactions to notes that harmonise well . It`s built into our ears and brains and it won`t go away despite a strange obsession with straight line frets . Lets all shave off our eyebrows and draw straight lines across the top .

amezcua
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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by amezcua » Sat Feb 10, 2018 9:21 am

Thr 16 replaceable frets in the Lou harrison site all have a straight line fret at the octave so I suspect these are altered ET tunings .Or maybe they are deliberately made to favour certain keys . Just swop the fretboard if you want the others .

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by Rasputin » Sun Feb 11, 2018 12:55 pm

Trevor Gore wrote:
Thu Feb 08, 2018 10:59 pm
hillguitar wrote:
Thu Feb 08, 2018 6:50 pm
http://hillguitar.blogspot.com/2018/01/ ... model.html

Kenny's latest comments on the issue.
Kenny (in the link) says " This is not a mode, or a different twelve note temperament — it’s good in all keys..."

Way back in this thread here I wondered about what temperament this system tunes to. Having read through the true temperament website, I still don't know. The best I could glean from it is there is more than one "tuning" and that if a certain one is chosen, other instruments in equal temperament won't sound out of tune with it. Kenny seems to hint that it's equal temperament, perhaps more accurate equal temperament than usual (because most guitar's don't do accurate equal temperament very well). However, I still don't know.

Can anyone enlighten me? Kenny?? Anyone?? /
Despite the name the basic true temperament system is to do with compensation rather than temperament. I looked at the website last time this came up and it said that their standard product is based on standard 12TET but they can also produce frets / fretboards for other temperaments. Putting that together with the quote from Kenny Hill, I am sure that this particular guitar will be an ET instrument, just with better compensation. The wiggly frets make it possible to take account of the fact that the amount of compensation you ideally want depends on what string you are talking about and how far up the fretboard you are. By the same token, the wiggles will have to be based on a particular choice of string / string tension, so you are stuck with that if you want to keep the full benefit of the improved compensation. Whether the system is worth the trouble, I don't know. I feel as though I am satisfied with the compensation that is possible with straight frets, but then again if I played one of these guitars for a while it's possible I'd find I didn't want to switch back.

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by amezcua » Tue Feb 13, 2018 9:28 am

Trevor and Rasputin are on the right track . I fitted a set of frets last night tuned to Kirnberger III and the telltale sign of aTemperament is the octave fret . This Kirnberger III has a definite wiggle at the octave with a straight bridge and nut. The Harmonics still happen in a straight line but the temperament shifts the fretted notes slightly . You have to trust the system .Now any scale starting on an open string sounds like a normal natural scale as a singer or violinist would perform . I still need to fit the last 3 frets or 2 and 2 bits .Then the ends need filing smooth . The nut bone for the bottom two strings is a bit low for the first fret . And the bridge bone is a tiny bit high for the 12 th fret .So the drawing system works . Making wiggly frets for a flat fretboard needs the fret to lay flat . I bought a pair of parrallel jaw pliers from Maun this week . My Maun wire cutters have been working well for 50 years so they are a good make . A few squeezes before fitting removes any wobble . Wiggles but no wobbles . But what will happen when I use real silk strings ? The thrill of the unknown . This is the first time I have fitted continuous frets right across the neck . No chance of snagging the strings now .

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by Rasputin » Tue Feb 13, 2018 5:34 pm

Wiggly frets at the 12th can still be compensation - even if the action is exactly the same for each string, the stretch involved in fretting the high E will still cause it to go sharp to a greater extent than the B next door, because the string tension is higher. The fretwire under the E should therefore be a little closer the the nut than is the case for the B. There is no nut / saddle compensation with this system so the 12th fret is not treated as a special case.

I wasn't aware that there were any (common) temperaments that did not use just octaves - I'm happy to be corrected on that, but if it's right it means that any wiggles in the 12th fret can only be do to with compensation, rather than temperament. The pitches will still differ depending on temperament, but that is because the open strings will be tuned differently. The frequency at the 12th will aways be double the frequency of the open string, i.e. it will always be a just octave.

I realise there is stretched tuning, but that's not a matter of temperament, and anyway I didn't think we had it on the guitar.

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by amezcua » Wed Feb 14, 2018 5:15 pm

The way I tuned these fret positions was not following a mathematical rule .It was following the Korg tuner. Each fret position ( or note ) was originally created from the Korg by comparing with the open string , tuned in the Kirnberger mode ,which is set in the tuner. The string was fretted at that note .That set the distance from the nut and the frequency at the same time. Nothing different happens when you play this guitar now. It`s all tuned by a Korg tuner . No mathematics needed .That`s the beauty of it . And no compensation .
I suppose the most awkward part of this is smoothing the ends of the frets which is a very standard job for a professional . The accumulation of note positions on the paper chart of the fretboard is the longest part. You must keep double checking the open string against each new note. The strings on this are not brand new but 3 of them are extremely accurate at the octave position .
Happily all the notes sound cleanly with no buzzing after I raised the bone nut with a tiny wedge. So no fret levelling is necessary . The bridge height was more accurate than I realised. The high e string needs to be a fraction lower .

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by hillguitar » Wed Feb 14, 2018 11:23 pm

The questions and speculations in this thread are all understandable and legitimate, and in the course of plunging into this experiment I have had the same thoughts, questions and doubts. I’ve recently written about my practical experience with this True Temperament system. In that blog most of these things are at least discussed, even if not conclusively settled. There is a lot more interest in this avenue than I would have expected. We’ve made 3 of these and have orders for more as we speak. I am acting as my own principal guinea pig.
Kenny Hill
Hill Guitar Company
Ben Lomond, CA 95005

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by hillguitar » Wed Feb 14, 2018 11:25 pm

Text of that aforementioned blog:

Some people have a problem with guitar intonation. I don’t mean just the struggle to get the 6 strings in tune with each other, I mean the accuracy of the the notes and intervals from fret to fret, string to string. Guitars have been around for quite a while now and guitar players have learned to live with it, but an accurate measurement of the pitches and harmonies would definitely show up compromises and discrepancies. For most of my life I’ve been perfectly content with the idiosyncrasies of the guitar fingerboard, and anyway I wasn’t aware of any other choices. That is, until now.

The True Temperament fretting system is a special development by Anders Thidell from Sweden. Several years ago my good friend Johannes Moller gave me a TT fretboard and frets that had been passed to him by the manufacturer. Johannes is also Swedish and a very prominent guitarist and composer and a clever and forward thinking fellow. I guess he figured I have tried a lot of progressive and innovative and weird things over the years, so why not give it a shot?

That first TT fingerboard and frets sat around in my shop for at least two years until I finally built a guitar with it on a whim. To be honest, I probably put it off because I thought it was a dead-end idea. I’m certainly very aware of the conundrum of guitar intonation and the compromises we learn to live with, but as a guitar player for over 50 years I’ve accustomed my ears to the reality of guitar intonation and I’m fine with it. In some ways I feel that the quirks and “imperfections” of the guitar are part of what makes it so lovable.


Nevertheless, that first TT guitar was really sweet. It was completed just before the Namm show, we took it with us to the show and it sold immediately. I barely had a chance to get acquainted. So with that tease I worked around trying to acquire more TT fretboards. It took quite a while to make a good connection with True Temperament but eventually I did get some more of these fingerboards and last year I made another similar guitar, which turned out just as sweet. Both of those guitars were Performance Model 650 scale, both spruce double top and both really delicious. Quite a few professional players tried out the second one and used it in performances, and everyone agreed there is something magical about it. So after these glimpses of this magic I decided to build one for myself. This way I could live with it in my daily routine of guitar stuff, practicing, performing, studying new pieces etc. I’ve gotten hooked on my Ergonomic designed Signature guitar, so that’s what I wanted, a Signature, Ergonomic, True Temperament cedar top with a Barbera pickup, all the bells and whistles. We made one, and I love it.

I’ve been playing this guitar for about 6 months now. I suppose I now have more experience with True Temperament on classical guitar than anyone. Over the years I’ve been willing to try many modern and sometimes controversial things in guitar innovation, and this one I was skeptical about. Because it’s so unusual and provocative looking, I kind of didn’t want it to be so good. But it is.

I don’t fully understand what’s going on with it, or the math and engineering that went into it’s invention. I do understand that although the fret position formula may be mathematically correct, the differences in the behavior of the individual strings because of their materials and design introduce a whole set of variables. And I understand that each individual note on the fingerboard is defined by it’s own beat-per-second frequency that can be measured, and if each note on each string were to have it’s own little fret, it might tune up more like a keyboard, but it would be pretty darn complicated. These curvy frets accomplish something like that in a dramatic but fairly practical way. I’ve read the FAQs TT has published, and I’ve thought about it a lot as I listen to it. I have a pretty good ear and can tune a guitar reliably and quickly. That’s not an issue. What I experience with the TT guitar is not so much a dramatic difference in tuning, but rather a lovely fresh purity to the sound, like extra fresh air and crystal clean water. It seems the various intervals are in greater harmony with each other, and the overall resonance is at greater peace and vitality. As I said, I’m not deeply bothered by the intonation of a traditional fretboard, but I am very excited about the overall countenance of the sound that comes out of my True Temperament guitar. This is not a mode, or a different twelve note temperament — it’s good in all keys, it sounds good all the way through my repertoire. And in spite of the wacky visuals it’s not hard to play for the left hand, there is no adapting of technique, that’s just not a problem.

Frankly the only downside to it is that it looks so unusual and provocative. It’s eye catching in a woozy way and I wind up having to try to explain it to people all the time. Since I am interested in it myself, I don’t mind talking about it, it helps me think about it and grow into some kind of broader understanding. But until it is much more common, it will be a topic of chit chat with customers and at any gigs that I play for a long time to come.

We’ll be making another True Temperament guitar here in the next few months. With three of them under my belt now and more to come, I’m convinced that this is a real option for players with a certain kind of discerning ear. I doubt that will become an industry standard any time soon, but for my own personal use I think it will be my choice for some time to come.

Kenny Hill
December 2017
Hill Guitar Company
Ben Lomond, CA 95005

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Trevor Gore
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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by Trevor Gore » Thu Feb 15, 2018 8:45 am

Well, although no one is prepared to overtly declare it, the wiggly frets, as far as we can tell, seem to be a way of achieving more accurate equal temperament.

There are much easier ways of doing that!

Many years ago I had a guitar that wouldn’t play in tune because the saddle was in the wrong place (a Suzuki copy of a Martin D). It was going to be touch and go as to whether there was enough room on the bridge to re-cut the saddle slot, so I wrote a small computer program to figure out where each string should end to have the guitar play in tune on the open strings and at the 12th fret – typical compensation practice. Having figured that out, I used much the same program to see how in tune the guitar would play on all the other frets and discovered what most guitarists (including me) already knew – that guitars tend to play sharp on the frets near the nut. Why that is, is a story for another day. But I modified the program to tell me where the frets should be in order to play accurate equal temperament on all strings and all frets. The results were frets in different places for each string, somewhat similar to the wiggly frets idea. Looking at this and doing a bit of analysis I found that the fret spacing for each string followed a 12th root of two rule (as you’d expect for equal temperament and uniform strings) with a minor modification to scale length for each string. This meant that the frets could all be shuffled into alignment with the strings ending in different places for each string. i.e. instead of moving the frets around relative to the string, the strings could be moved around relative to the frets to achieve the same effect, bringing all the frets back into straight lines. This is, of course, nut and saddle compensation. Others have come to much the same end point by different thought processes, and have proposed various schemes for calculating nut and saddle compensation, usually involving also having to calculate some new custom scale length to use when computing the fret positions using the 12th root of 2 method. One such method was recently written up by Magliari and MacRostie in American Lutherie #116, (Winter 2013) and discussed online here. However, rather than re-computing fret divisions to suit a particular (average) string length, it is possible to have the fret spacings the same for all strings and adjust the string lengths to suit on a per string basis, by making an additional adjustment to the nut and saddle compensation.

DSCF9472cs.jpg

So what that means is that the player gets to hear accurate equal temperament and all the benefits of that which Kenny talks about, with conventional straight frets spaced on a standard scale length by using optimised nut and saddle compensation. If you change your set-up or string types, ideally you will need a new nut and saddle. Much easier than changing the fretboard. But, generally, even with a different set-up, any decent nut and saddle compensation is better than none.

All the supporting mathematics, modeling and charts etc. can be found in the book.
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Trevor Gore: Classical Guitar Design and Build

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by Rasputin » Thu Feb 15, 2018 12:03 pm

Trevor Gore wrote:
Thu Feb 15, 2018 8:45 am
Well, although no one is prepared to overtly declare it, the wiggly frets, as far as we can tell, seem to be a way of achieving more accurate equal temperament.
Or in other words better intonation on an equal temperament instrument - I think the blog extract makes that pretty clear to be honest, and the following is the extract from the TT website that I had in mind in my previous post:

What does “True Temperament” mean?
The TRUE TEMPERAMENT™ Fretting System is a revolutionary new way to construct guitar fingerboards which tune accurately along the whole neck.

TRUE TEMPERAMENT™ does not imply Just Intonation. It is physically impossible to implement Just Intonation in more than one specific key (and its relative minor) on any instrument with only 12 intervals in the octave. (Except perhaps for computer-controlled instruments using electronically generated sounds.)

What we mean by TRUE TEMPERAMENT™ is that our fretting system will give you super-accurate intonation over the whole fingerboard in the temperament it is constructed for.

Back to top

What’s wrong with straight frets?
Standard equal tempered fret spacing is calculated from one single piece of information about the instrument – the scale length (the theoretical speaking length of the open strings). A divisor constant is used to determine the locations of the frets. The scale length divided by the constant gives the position of the first fret. The remaining length after subtracting the first fret, divided by the same constant, gives the position of the second fret, and so on.

The divisor used by all but a vanishingly small percentage of modern guitar builders is 17.817152, a figure arrived at by way of the logarithmic function “the 12th root of 2” (1.0594631). This results in precise mathematical fret spacing with the 12th fret at the exact centre of the calculated scale length. If the calculation is repeated for 24 frets, the distance from the 24th fret to the theoretical bridge saddle position will be exactly one-fourth of the calculated scale length. (The residual error is ridiculously small, less than one ten thousandth of an inch on popular guitar scales.) All very impressive. But this mathematical model is a gross oversimplification. It ignores virtually every physical parameter which governs the behaviour of vibrating strings, except one – speaking length. Tension and mass are not even considered.

The model assumes an “ideal” or “perfect” string – one which only exists in theory, not in the real world. It assumes, firstly, that the strings have no stiffness. Secondly, it assumes that all strings behave identically, regardless of their thickness, whether they are plain or wound, and the material they are made of. Thirdly, it assumes zero string height – and completely ignores what happens when the strings are pressed down on the frets!

The frequency of a vibrating string is determined by three factors: the speaking length, its mass, and the tension applied. All three of these factors are affected to varying degrees when a string is pressed down on a fret. Along the neck, the length and mass decrease by 50% per octave. Changing the length affects the stiffness. The tension is affected by fretting the string, as the string height is not zero. Pressing the string to the fret stretches the string slightly, increasing the tension and thus sharpening the notes produced.

The strings themselves vary considerably in diameter and construction (plain or wound), and thus react differently to being fretted. One single adjustment per string at the bridge (“intonation”) cannot possibly fully compensate for all these parameters at once, as they all vary in different degrees on different strings.

The only way to fully compensate for all these parameters is to adjust each and every string-to-fret contact point on the fingerboard separately, until each and every note plays the target frequency exactly. This, which is impossible on a guitar with traditional, one-piece, straight frets, is exactly what we do with Dynamic Intonation™, and Curved Frets™.

I don't think it could be much clearer that we are talking about a system of compensation that can be applied to any tuning system but with the assumption that equal temperament is going to be the norm.

I haven't had time to look at the maths in the article Trevor linked to but anything that comes out in a conclusion that the frets should be straight (for ET) is either ignoring the other factors mentioned in the extract above or demonstrating that they cancel out. I can't think of any reason why they would cancel out, especially bearing in mind that all the strings are different.

As in all things musical, the ear should be the final judge. Having said:
Rasputin wrote:
Sun Feb 11, 2018 12:55 pm
The wiggly frets make it possible to take account of the fact that the amount of compensation you ideally want depends on what string you are talking about and how far up the fretboard you are. By the same token, the wiggles will have to be based on a particular choice of string / string tension, so you are stuck with that if you want to keep the full benefit of the improved compensation. Whether the system is worth the trouble, I don't know. I feel as though I am satisfied with the compensation that is possible with straight frets, but then again if I played one of these guitars for a while it's possible I'd find I didn't want to switch back.
I am very interested in Kenny's comment that:
hillguitar wrote:
Wed Feb 14, 2018 11:25 pm
What I experience with the TT guitar is not so much a dramatic difference in tuning, but rather a lovely fresh purity to the sound, like extra fresh air and crystal clean water. It seems the various intervals are in greater harmony with each other, and the overall resonance is at greater peace and vitality. As I said, I’m not deeply bothered by the intonation of a traditional fretboard, but I am very excited about the overall countenance of the sound that comes out of my True Temperament guitar.
What I am not clear about is how much the wiggles would theoretically have to change if you moved say from hard tension to medium, or maybe gut, nylgut etc. There is a clue on the TT site where it say that it is OK to tune a half-step down, but does that mean OK as in no worse than if you had straight frets, or OK as in you are still getting most of the benefit of the wiggles?

The other downside that it may be difficult to resell such a strange and terrifying beast, but guitars are so hard to resell anyway that it's best to buy for keeps.

We play in comparatively few keys and it is not so difficult to envisage a system of interchangeable fretboards where you can pop out your (true temperament) A major well tempered board and change it for your D minor without removing the strings. Not that I see much of a market for that...

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petermc61
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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by petermc61 » Thu Feb 15, 2018 12:12 pm

I concur with Trevor’s advice above. In fact, I raised that very same comment early in the thread.

I know it works because Trevor ran his program on a guitar from a very famous luthier I owned that was not playing in tune and made me a customised saddle and nut. I had never seen a nut or saddle with so much different compensation between strings. After completion, the guitar had compensation errors across the fretboard (at least up to the 15th fret we chose to optomise over) if only a few cents. It also sounded better, purer and more musical. The intonation accuracy Trevor achieved is better than most people can achieve in practice through imprecise finger placement or pressure.

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by Rasputin » Thu Feb 15, 2018 12:26 pm

Well yes, but you didn't compare it against a wiggly fret version so you can't say that you wouldn't have got even more of the same out of the TT system. I think everyone appreciates that the traditional compensation system does work relatively well - the TT folks are not saying otherwise.

I was just looking at their site and a routed fingerboard with loose frets is about £400 once you've paid shipping and (UK) VAT. I don't know what a luthier would charge to swap the boards over (any guesses?) but it seems as though the cost is high enough that you would be wanting to specify TT on a new instrument or buy one of Kenny's rather than having the surgery performed on your existing SWO.

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Re: Kenny Hill's new performance intonation "wiggly" fretting

Post by bacsidoan » Thu Feb 15, 2018 2:58 pm

Being an owner of a classical guitar built by Trevor Gore, I can attest that the intonation of his guitar is within 2 cents across all strings, all registers so long as one uses the strings that he fabricated the nut and saddle for. Yes, I did spend time measuring the frequencies at all registers with a Peterson Strobe Tuner. There's no doubt in my mind that the nut and saddle compensation scheme works if done correctly, not just relatively well but second to none for the conventional equal temperament in so far as accuracy is concerned. I'm not in position to comment on the musicality of equal temperament versus others. It is unclear to me based on the info provided by the TT folks whether they follow the equal temperament scheme or use the Thidell formula (or other similar ones) to calculate the frequencies. This quoted statement clearly displays the ambiguity to their advantage:

"What we mean by TRUE TEMPERAMENT™ is that our fretting system will give you super-accurate intonation over the whole fingerboard in the temperament it is constructed for."

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