Adjustable Intonation Nut

[McSeem]

Hi,

While tuning the saddle intonation I've noticed the first frets sound too sharp, up to +6 cents, while the tune is perfect at the 12th fret. I use a very accurate software strobe tuner: http://www.tbstrobetuner.com/

It's quite understandable: the nut is supposed to be slightly higher. That is, the distance between the string and the 1st fret strip must be a bit bigger than the distance on the 2nd fret, when you hold the 1st one (yes, I've read an article about the nut tuning). So that, the difference in string tension is higher on the first frets, while on the last frets it's compensated with the saddles. Long time ago I tried to replace the nut with a metal strip and a spacer behind it, and then polished it together with the other strips, as if your fret board was extended. I did everything very carefully, and the intonation was perfect. But there was another problem: open stings interfered with the first strips! Why? The string height was the same and it was very accurate. The answer is: open strings sound brighter, with stronger high harmonics. Your finger damps high harmonics, even though, the string lies on the metal strip! The string is also vibrating lengthwise, so, your finger removes high harmonic energy. The difference is very slight, but it's enough to make open strings interfere with the strips. This is why the nut must be slightly higher, or, otherwise there must be a damper above the nut that imitates your fingers. But I assume the guitar players do not appreciate it, because it's nice to have a bright sound of open strings. As the result, first frets sound sharper and you can't compensate it with the saddle intonation. The solution is to have an adjustable nut. Not just adjustable height, but most of all, individually adjustable positions!

I could only find these ones: http://www.earvana.com/products.htm

But they all are pre-fixed and adjusted for average strings, while there can be a huge difference, especially on light and heavy strings. Wound and unwound G string also makes a huge difference.

So that I came up with an idea of fully adjustable nut. It's not about the height, it's only about the position. I have a couple of versions of the design in my mind, and my main question is: in your opinion, how cool would it be to have this kind of a nut? Is it worth giving a try, or it doesn't make much sense?

McSeem

[WezV]

not sure i would want adjustable for tone reasons - i prefer something thats pretty solid and anything adjustable needs to make sure its not going to be a cause of rattles

but have a read of this to get you started

http://www.mimf.com/nutcomp/index.htm

[McSeem]

not sure i would want adjustable for tone reasons - i prefer something thats pretty solid and anything adjustable needs to make sure its not going to be a cause of rattles

but have a read of this to get you started

http://www.mimf.com/nutcomp/index.htm

This is why I'm asking the question, because I'm not sure either. But assuming I can come up with a reliable design, I have a feeling it makes sense. Thanks for the article. They also use a kind of a pre-fixed positioning, and BTW, it looks very different from this ones: http://www.earvana.com/products.htm

In particular because of a wound G string, which proves that the adjustment heavily depends on the strings.

McSeem

[WezV]

i think setting up a solid nut for the averages on a certain guitar is a better idea - which is what the earvana does - and they have acoustic versions for a wound 3rd. These are still a vast improvemnt over a standard nut... and a standard nut is close enough for msot

Of course on a guitar that you know will have one set-up for a long period of time it may be worth going to the extra effort to create an individual nut for it that suits that specific set-up

...

but i will be interested to see what you come up with

[Tim37]

ok i have never really understood the buzzfeiten nut but from what i could gather isnt it set up for the indivdual guitar? or is it like the earvana nut that is just and average compensated nut.

[McSeem]

ok i have never really understood the buzzfeiten nut but from what i could gather isnt it set up for the indivdual guitar? or is it like the earvana nut that is just and average compensated nut.

The buzzfeiten nut is not adjustable, basically they just shorten the first fret space and then compensate everything with the saddles. And, yes, the compensation is different for different guitars, but it mostly depends on the strings, so, when you decide to use different strings, you have to re-adjust the intonation. Both Earvana, and Buzzfeiten use just average compensation. Maybe that's good enough, but definitely not perfect.

[WezV]

BF use a 'sweetened' tuning system as well... where as an earvana can be tuned with a normal cheap ass tuner

perfection is an impossible goal, somehow my parents managed it

but if you can make an adjustable nut then there is certainly a market.... notice though how the earvana never really took off in its slightly adjustable version because it looks damn ugly. once they did one that looked a bit more standard (possibly compromising perfect tuning in the process) it became a lot more marketable

[McSeem]

Yes, AFAIU, there's no way to tune buzzfeiten without a precise strobe, because you have to take care of special offsets. While an adjustable nut would require a precise strobe only to set the intonation itself, and then you can tune your guitar as usual.

Well, any nut with individual compensation requires different positioning, that's why it looks ugly, but maybe it's just a matter of habits. Afterall, you can say the bridge with a strange saddle pattern also looks ugly. Instead, maybe this uneven "nut pattern" with individual screws may look super cool... to players who understand it :-)

as an option, it's also possible to use some cover to hide it.

[soapbarstrat]

but if you can make an adjustable nut then there is certainly a market....

Probably not enough of a market to make it worthwhile. Funny how the guitars where BF is needed the most are the ones with improper action height at the nut. That's what the BF market looks like to me; guys who are pretty clueless about proper action height but want to spend big bucks to "correct it", bypassing reasonable bucks to have the standard nut height tweaked.

[McSeem]

That's what the BF market looks like to me; guys who are pretty clueless about proper action height but want to spend big bucks to "correct it", bypassing reasonable bucks to have the standard nut height tweaked.

Yes, there's a point. Sharper notes appear mostly because of too high nut. However, the proper nut adjustment is described here: http://www.projectguitar.com/tut/nuthigh.htm

And even in this case, and with the proper neck adjustment you still have some sharpness, up to 3-5 cents on low frets. I even made the nut slightly lower than described, like 0.003". Another thing to consider is that, when you "deflect" your string at the nut (1st fret) you add more extra tension than when you do that in the middle, assuming the same height, say, 0.5 mm. you can take a calculator and recall the Pifagor theorem. That's pretty straightforward. And you can't compensate the intonation on low frets with the bridge.

As I said you can achieve perfect tuning if you add one more fret and a spacer behind it. But in this case open strings will rattle.

Besides, different strings have different tension parameters, this is why you have to set up the saddles differently. Say, unwound G string needs more compensation.

Besides, the tune depends on the strength of pressing. If you press the string stronger, you add extra 3-10 cents. It will be also nice to compensate it for average pressing. Just straight physics. Well, I'm just trying to convince myself that it all makes sense. :-) Maybe it doesn't...

[soapbarstrat]

However, the proper nut adjustment is described here: http://www.projectguitar.com/tut/nuthigh.htm

Hmmm, I can't assume he nailed it in that tutorial. Not sure about that .005" gap, 'cause it's a different way than how I check, because I don't like standard feeler gauges for measuring string space gaps, cause the gauges are too wide.

I like to use short pieces of guitar string as gauges, and those don't get below .008", so I measure the fret/string gap at the 1st fret without the string being fretted. On the high E, I'm going for a maximum of .010" (you can sometimes go down to .004" here). Add about .005" on the low E, but often that can be lower. Going a tad bit higher isn't out of the question if someone tells me they like it a little stiff, but stiff to me is .013" high E, .018" low E.

[verhoevenc]

www.elutherie.org ... they have one. I think it's a waste of time/money for MINIMAL rewards.

Chris

[SwedishLuthier]

We have had the adjustable/compensated nut debate several times. I think all of us agree that perfect pitch is neither possible or decirable (hence the tempered piano that has the ability to actually play more than one scale...). Most of us also agree in that an adjusted/adjustable/compensated nut will indeed improve intonation on the first frets. Now, how to do that? Either a fixed compensation (Buzz Feiten, or similar like Perry does) or an adjustable like the Earvana. It's no secret that I use Earvana for most of my builds. Nearly every time I discuss a build with a customer I give them a chanse to play a guitar with standard nut and one with an Earvana nut. Up to today I have only had one single customer that have opted for the standard nut. That, to me, is proof that the system is not only good in my ears, but also in my customers ears. But as you say, it is only suitable for unwound G-string. However the all-over adjustments makes it good enought (remember that tuning is only an aproximation) with all string gauges I have tried up to now. But a solution with individually adjustable sadle slots is an interesting consept. However I suspect that you in the end will end up with a curve similar to the on used with Earvana sadles. Interesting enough that curve is more or less a mirror of the TruTemperament frets, meaning you have the same compensation, only in a different place...

[McSeem]

www.elutherie.org - yeah, that's a monster design. It also requires a body-mounted tuner. My design, that I keep in mind, is way much simpler. Although, it requires some minimal woodworks. We will see.

Hmmm, I can't assume he nailed it in that tutorial. Not sure about that .005" gap, 'cause it's a different way than how I check, because I don't like standard feeler gauges for measuring string space gaps, cause the gauges are too wide.

I like to use short pieces of guitar string as gauges, and those don't get below .008", so I measure the fret/string gap at the 1st fret without the string being fretted.

Yes, that's another way of adjusting the height. However, this method is less precise; your distances depend on the string height at the 12th fret. I just saw the recommendation I mentioned several times. Graphtech also recommends to do the same. I agree, standard gauges are too wide. I used stacked pieces of clear tape, measured with a fine caliper. Then you cut your gauges as you want. The "3rd fret" method makes sense, because it's more accurate. If your strings at 3rd fret slightly touch the 2nd, it means the nut height is exactly equal to the fret height. However, you do want your nut to be slightly higher than fretted strings to prevent from fret buzz on open strings when you play hard. High harmonics are stronger on open strings.

[soapbarstrat]

However, this method is less precise; your distances depend on the string height at the 12th fret.

For what it's worth, I first capo the 1st, measure 12th fret action, then work on nut action, rechecking 12th fret action just before making the final tweaks at the nut. And I'll admit, I'm about as fussy as they come about playabilty, but I cut a little slack with perfect tuning. Very small percentage of guitar recordings have knocked my socks off in 41 years, but all the ones that have, were apparently on guitars with un-"compensated" nuts.

But yeah, if you want to make a scaled down tune-o-matic nut, wish you all the best.

[Mattia]

A lot of big factories, even those that don't use compensated nuts or Buzz Feiten's full system, trim a little off the nut end of the fingerboard, to the tune of about half a mm or so. You kind of do this automatically when slotting a fingerboard, as the 'middle' of the slot - fret position - is a little further back than the edge of the 'slot' used for your nut.

Edited May 20, 2010 by Mattia

[verhoevenc]

I know guys that take off even more than half a fret's width.

Chris

[psw]

I looked into this for a while...rejected the ugly things available...so I doubt there is a market...

The lower strings of a guitar are inherently out of tune, that is the way it is, can be improved...or you can avoid a lot of it with playing technique like I do.

I did play with this a bit on my acoustic...adding some shims of nut material in front of the nut to bring it forward.

I also added an LSR to the last build, which means cutting into the fingerboard...not for your average person to do...so not a fit and play proposition, and I was conscious that if it wasn't as good as I ahd hoped...I had made a big commitment to the thing by cutting out the slot...no going back! This would be a huge deterrent...real custom builders can do it themselves for the instrument and players, string gauges and such in question.

By far the biggest problem is badly set up guitars...oh, and bad players...they too aren't going to be cutting into their guitars...

However, a height adjustable nut, like the way an LSR fits may well be something interesting...certainly makes setting up the nut a whole lot easier to get perfect. A really good set up on a decent guitar should end up pretty darn good...

So, sure why not, but everyone is going to wasn't something different, different string spacings, different curvature, different string gauges...it would be a production nightmare...and having to carve up a guitars fretboard is going to turn most people off right there. Then there is the various guitar's headstocks, string splaying...and of course, you got to make it from a material that will allow for tremolo systems...and then compete with all the products already hyped up on the market.

There is something to it, but the better the set up, the less there is, the better the player and you won't even hear it.

Coincidentally I am working on a new neut concept for my new guitar in the works...maybe I should look into compensating a little...is there a table of 'offsets for such things, or is it done by ear? How do you guys work out how far forward to move the nut and for different strings?

...

hahaha...I just remembered...a lot of guys push so hard into those jumbo frets, they sound out of tune where ever they play...can't imagine the sound on a scalloped fretboard...

[WezV]

How do you guys work out how far forward to move the nut and for different strings?

http://www.mimf.com/nutcomp/index.htm

[McSeem]

Coincidentally I am working on a new neut concept for my new guitar in the works...maybe I should look into compensating a little...is there a table of 'offsets for such things, or is it done by ear? How do you guys work out how far forward to move the nut and for different strings?

It's trivial -- with a precise strobe tuner. You set the bridge intonation first, then adjust the nut slots so that the first frets would be exactly in tune. If the 1st to 3rd frets are too sharp, you move the slot closer to the bridge.

hahaha...I just remembered...a lot of guys push so hard into those jumbo frets, they sound out of tune where ever they play...can't imagine the sound on a scalloped fretboard...

Long time ago I also filed and sanded an acoustic guitar neck to make a very low-profile fret board. I didn't notice ANYTHING bad about it, compared with the regular-height frets. So, why they make them so high?

[psw]

Thanks wez...

See, you need a precise tuner, and differing compensation for each string...so, not for your average tinkering guitar player...so a select market. Something that would work on all guitars, be height adjustable and didn't require any mods to the guitar might be at least a pre-requisite for any 'venture'...but even then the market is so small compared to the cost or producing such a product...as this seems to be the aim, it is likely to disappoint as a marketing venture I suspect...

You can't fight what people like...there are reasons to have bigger frets and such...but really, there are some benefits to advanced players too. If you use jumbo frets and a good technique, your touch should be such that you are only pressing down enough to sound a note...so there is no fretboard contact and hardly any friction. It certainly can be a different feel, imagine playing a scalloped board with no fretboard at all under the fingers...or a sitar...

Now, a really advanced player can also compensate for some tuning anomalies by pressing a little harder into some notes of a chord to bring things into 'tune'.

I tend to avoid a lot of chording of say A major in open position as that C# on the b string is a typical problem. Minor chords don't sound so bad, but it's those maj3rds that get you everytime. Avoid the b string in the very lowest frets for such intervals. Remember the whole temperament of western diatonic tuning is out of whack with the more 'natural' order of things and major thirds are the biggest problem to the ear. You will notice that a lot of music now days, just avoids them all together, hence the power chord.

That's not to say that it wouldn't be nice to have a guitar that plays a bit more "in tune" but with all the fussing over strobe tuners or BF offsets and special notes that permanently alter a guitar...and the fact that the people you are playing with are unlikely to be using the same tuning system...how many are really going to want to invest in such a scheme on their prized instrument.

I loved the LSR on my last project, but in truth, it is about 1mm too wide for a squier over a real fender....and I'd consider it even with my LP project with trem, but it is completely wrong for that one in terms of width and not prepared to cut the board to make the thing work. The same concerns should face anyone considering such an "innovation" as you propose. So, if thinking commercially (no reason not to make things for yourself of course) I doubt that you are on a winner there...also, I believe there are a number of patent already and if you were to attempt it, someone would sue or close you down, and very unlikely that you'd get a patent yourself for such a thing.

In fact, I don't have time to look it up...but there has been something very similar to what you proposed on a commercial guitar before...a little obscure and in some of my books...and not the prettiest thing...but the whole nut job was a commercial failure there too and was decades ago...so you know...just saying, these are the things that need to be considered.

I doubt that you will have many takers to go back to the old frettless wonders of the 50's, though I admit I quite liked them too. But having recently switched guitars again and going back to quite high jumbo frets and lower action, I'm quite liking the slinky feel of the things...and less out of tune-i-ness than the higher action, lower fret tele I've been playing the last couple of years (good as that is).

But then, I don't play with much distortion at all...the way a lot of people play guitar the issue of primarily open high strings on the lower fret area is hardly a concern, and you are rarely going to hear a maj3rd interval down there these days on guitar anyway.

[soapbarstrat]

hahaha...I just remembered...a lot of guys push so hard into those jumbo frets, they sound out of tune where ever they play...can't imagine the sound on a scalloped fretboard...

That kind of playing technique becomes painful pretty fast, especially continuing to press too hard at the 1st fret. I'll just assume the guys who never adjust accordingly are the guys who just pull the guitar out of the closet once in a blue moon.

Overly stiff nut action (forcing my fretting hand to act like a pair of vise-grips) is almost always what cripples my fretting hand.

[McSeem]

I don't have any serious goals on it. My first goal is to check whether or not it makes sense at all. That's a low priority project, so, before drilling and milling, I want to collect your opinions. Thanks a lot!!! Maybe one day I'll try it, but not sure. As for potential marketing, well, it's big question anyways. The musicians are conservative, and I totally realize that.

[Mender]

I have never understood the reasoning behind having the nut slots a little higher than the fret height. It makes no sense to me. After all, the first fret is no higher than the second, the second is no higher than the third etc. Surely the nut slots should be exactly the same height as the frets. For this reason, I use a zero fret on my builds, and I don't hear any "out of tune" notes on the first few frets. Obviously, it isn't perfect, just the well known foible of guitar design, but it is definitely better than nut slots set higher than the frets.

An added advantage of a zero fret is that fretting at the first fret is just as easy as fretting at any other fret, and open strings have the same tone as fretted strings

Edited May 21, 2010 by Mender

[McSeem]

Well, of course, the "zero fret" gives you pretty good tune. However, the nut does make sense in terms of better behavior with the tremolo bar -- the nut must be permanently lubricated, for example, Graphtech sells their special teflon nuts. Another reason is that, open strings produce stronger high harmonics, with bigger vibration amplitude near the next fret. It happens because strings are also vibrating lengthwise, and your finger dumps high harmonics, while the nut doesn't. So that, open strings with the "zero fret", or a nut adjusted exactly to the fret height, will tend to interfere with the 1st fret when you play hard, so that, you have to set the strings higher at the 12th fret to compensate it -- I did that experiment long time ago with an acoustic guitar.

After all, the first fret is no higher than the second, the second is no higher than the third etc.

That's incorrect. Although, all frets have exactly the same height, a string fretted on 1st is higher than open (assuming the zero fret) a string, fretted on 12th is significantly higher at 13th -- just straight geometry.

One more possible reason (maybe even the major one) - is that you can easily add extra 3-10 cents if you push your string stronger. And this effect is significant namely on the low frets, while the high frets can be compensated with the bridge. So that, you can potentially adjust the nut slots positions to compensate the average pressing strength.

This is my rationale.

Although, I agree, it doesn't make much sense for an average guitar player.