Floating Bridge Angle - Intonation with 11/49 string set

[PTChristopher]

>>> I would never imagine that only the core counts [...] So i guess it explains why on flat top acoustics one can often see a B string compensated saddle : the B has a bigger core than a wound G ! Wow ...

Yep. That's it. So it turns out that you are expert in this, we just can benefit by taking a little time to connect all the stuff you already noticed. Go figure.

Chris

[xuoham]

Stretch #3 is easy to describe (so a nice break).

Stretch #3 comes from lateral movement of the string along the fret. It is how we bend notes.

Another thing that might seem unsettling when trying to do a diy setup instead of going to a pro is the variable of finger pressure on a fretted note, especially with tall frets and the big wound strings, pushing harder sharpens the note...
Do you consider this also is the Stretch #3?

I guess that's what you mean when you write:

... it is pretty easy for most advanced players to "naturally" add little left-hand squeezes...

[PTChristopher]

>>> Another thing that might seem unsettling when trying to do a diy setup instead of going to a pro is the variable of finger pressure on a fretted note, especially with tall frets and the big wound strings, pushing harder sharpens the note...

Definitely. It is a big part of the picture. it is also funny when someone obsesses over the exact pitch of a note at the 12th fret, and adjusts it with the guitar laying on a table (or workbench) until it is "perfect".

Then plays the guitar in a sitting position, with a completely different grip and pressure on the frets.

>>> Do you consider this also is the Stretch #3?

No. But you have introduced Stretch #4 perfectly. Back in a little bit.

Fun exchange of posts here Paul.

Chris

[PTChristopher]

>>> Another thing that might seem unsettling when trying to do a diy setup instead of going to a pro is

In my opinion you have the understanding to do a better job of setting up your guitar than many pros will do. We just need to connect the dots in a few places.

In my opinion.

Chris

[PTChristopher]

And Stretch #4: (With a more punchy, short writing style since I am also watching the 'Niners / Bears game.)

We press strings down to make contact with the frets. But we do not stop at the exact moment that we contact the frets. We press the strings down PAST the tops of the fret crowns to various degrees.

We all do it.

It is unavoidable.

This hyper-extension of the string past the fret crown adds further stretch. This added stretch is #4.

It varies VERY widely from player to player, and it varies as we play up the FB.

Like all stretches, it makes notes sharp.

For most players the effect is strongest down by the nut.

The lower fret positions leave a greater span of string between frets. This is no big news. But it means that a given finger pressure will move the string deeper past the fret crowns at the second fret than it will at the 15th.

Some players play right up just behind the frets, others press more in the middle between frets. This matters.

IN GENERAL:

Stretch #4 is a bigger factor in low playing positions and has far less effect as we play up the FB. This is because it is simply much harder to press the string past the fret crowns and down toward the FB when the span between frets is shorter.

Stretch #4 is corrected, when needed, by NUT COMPENSATION. You move the nut forward toward the bridge. This compensates for the sharpness caused by Stretch #4, and works most effectively in low positions. The "ideal" amount of nut compensation varies for each string. Nut compensation has very little effect as you play farther up the FB.

Higher frets, lighter strings, and heavy left hand technique all contribute to stretch #4.

It makes perfect sense that some players will find a compensated nut to be a miracle of intonation improvement, while others will say it makes no difference. They can both be absolutely right based on their specific circumstances.

Compensated nuts are nothing new. I sneak nuts forward about 0.5mm. This is not really a careful compensation, but for me it results is noticeably better overall intonation as I have gone to higher frets over the years.

Adding small shims in front of the nut at the B string (effectively moving the nut forward for the B string) is an old trick to solve low position intonation troubles for cowboy chord strummers who are very strong.

The Feiten and Earvana systems offer a compensated nut. They both have their problems in my opinion.

The Feiten system is a set of nut compensation and bridge compensation offsets. It is heavily marketed in what I personally find to be an irritating manner. There is no magic here. I do not wish to argue with anyone who has found the Buzz experience to have improved the quality of their lives. I suppose it makes food taste better too.

Now that I have that out of my system, the Feiten product and process (via a trained Feiten installer) adds a set of nut compensations that are better than nothing for some players, and a set of "intonation" offsets that attempt to address the fairly classic, and more often noticed artifacts of guitar intonation "errors". In my opinion, a luthier who understands nut compensation can do a better job (and without the dopey BS) if you have low position intonation troubles.

The Earvana is, in my opinion, a more honest approach and presentation of a compensated nut. The one problem, and it is a big one in my opinion, is that the Earvana sort of groups Stretch #2 and #4 together and claims to fix them both. And indeed it does improve them both.

But in a way the Earvana description and approach encourages sloppy set ups. Again, a luthier who understands nut compensation can do a better job - even if just by adapting an Earvana for a better basic setup followed by nut compensation.

Chris

[PTChristopher]

And so to respond to vejesse from last night:

>>> If you play within the first three frets the notes appear to sound more sharp then they do farther up the neck. This is due to increased tension because of proximity to the height of the nut.

Respectfully, this is just the Buzz Feiten marketing text. The "first three frets" is really a dumbing WAY down of the idea that some intonation artifacts are stronger near the nut and become progressively weaker as you play up the FB. Nothing magic happens in the "first three frets".

>>> This is due to increased tension because of proximity to the height of the nut.

Only if the nut is too high. The solution is not to pay for a miracle diet, an exercise machine that fits in your pocket, or an over-sold intonation miracle system. Get the nut to the right height.

>>> Wound strings seem to be worse,

I do not find this to be the case at all.

>>> By moving the nut closer to the bridge you counter act the tensioning effect by lowering the pitch.

Agreed that moving the nut closer to the bridge counters the effects of Stretch #2 and #4. But FAR better to first get rid of #2, then compensate for #4 in those somewhat rare cases where it is a genuine practical problem for a player. Don't do a crappy nut set-up then throw compensation at it to hide the artifacts. In my opinion.

>>> ok, I can see it, especially if you spend most of time playing cowboy chords.

Indeed. The most common genuine practical improvement via a compensated nut is for strong cowboy chord players. This even makes sense.

>>> But why change the compensation at the bridge if you play mostly up the neck?

The bridge compensates Stretch #1 regardless of where you play in the neck. But it does has only a minor effect down in very low positions.

>>> Is [nut compensation] worth the trouble?

For some players, absolutely. For others there will be no benefit at all. For some it will do active harm if it hides the significant "playability" downsides of a high nut by masking the low position intonation artifacts of a hugh nut.

To me this is the "problem" with the Earvana sales pitch. If they emphasized getting the nut height right, THEN looking to nut compensation, I'd be all set.

But I think having me be "all set" is not a priority for either commercialized compensated nut product.

All in my opinion.

Chris

[PTChristopher]

OK, I'm typed out.

I hope this is of some interest.

Chris

[oldane]

OK, I'm typed out.

I hope this is of some interest.

Chris

Very much so, Chris. You have given a very thorough walktrough of the complexities of guitar intonation. And you have - by explaining some of those complexieties - also given an illustration of the futility in the concept of absolutely perfect intonation. We should get as close as we can but must accept that with a guitar, we are dealing with something less than perfect. We must also limit our reach for perfection to where it makes a significant audible difference in real life music making. As Max Berek said: "Perfection within reason." Max Berek was the designer of the lenses for the first Leica cameras - and every photo freak knows how good they were.

(Oldane, we will definitely get to your angle on low nuts and the effect of relief as well. But right now I hope to stick to getting us all on the same page with regard to the ways strings stretch.)

Ah, you know my pet subjects from previous threads. Now that you bring it up........

Yes, relief affects intonation and thus the need for compensation. With some relief in the neck, the fretboard so to speak bows up to meet the string in the higher positions, so your stretch #1 is deminished which calls for a different compensation as compared to a completey straight neck. In my humble experience, not two guitar neck bows in exacly the same way when setting a bit of relief with the truss rod. Some bow more near the nut, some bow more near the body. Others bow a little more at the bass side than on the treble side. Etc., etc. A guitar neck is an imperfect wood object. I like a bit of relief, especially with a higher action like I use on the guitars I use for acoustic rhythm strumming, because I like the way it "equalizes" the fretting resistance (stretch #1) along the whole neck. With a perfectly straight neck, the fretting resistance tends to increases up the neck. It doesn't mean so much with a low action but with a high action, it can be felt. The old big band guitarists almost always had some relief in their guitar necks. Neck relief is very much a matter of personal preference. Bob Bendetto in his video from his guitar making couse in the 1990s said that guitar necks should be straight. OTOH, at least as late as the 1970s, Gibson adviced to keep a little relief in guitar necks to avoid buzzes.

This brings us to the subject of unwanted high pitched buzzes - originating from the part of the string between the fretted note and the nut. With a perfectly straight fretboard and a nut witch is exactly on line with the frets (not higher), one is is asking for buzzes behind the fretted note, which may not mean a lot on an electric guitar, because it's not heard through the amp, but it can get on the players nerves (at least mine) with an acoustic guitar. The answer to this is setting the neck up with a bit of relief and/or having the nut a tiny fraction of a millimeter higher than your (Chris') ideal nut (that is perfectly in line with the frets). This introduces some alterations to the intonation, which may or may not have to be dealt with.

On top of all this, some newcomers to the guitar are surprised by the imperfections of the tonal intervals themselves, which led to the development of the tempered tuning system at the time of Johann Sebastian Bach. Any attempt to overcome this by "compensation" is of course futile. Attempts to force one interval into total perfection, will only push other intervals into greater imperfection.

Chris, I agree perfectly with you. I just want to add a further illustration of of how complex and individual the socalled ideal setup is - an how we have to live with compromizes because even a well made guitar is very much an imperfect item, and because various corrections to take this or that into account may pull the intonation in both a better or a worse direction.

[vejesse]

Wow PTChristopher, this was a lot of work. I don't think I've seen a text like this out there, well done.

Here's one more thing: Have you considered the inharmonicity of the string itself, that is the tendency of the partials to stretch because of string stiffness? I find that if I try to stretch the tuning a tiny bit like a piano tuner might do it seems to make the guitar sound better. But it may be my imagination. If I tune every string to an "E" it seems to work better as well - I've been doing that as long as I can remember. And I was surprised to read the Buzz Feiten guys suggest that as well if you don't have access to a tuner for their special offsets.

You say you move the whole nut forward by .5 mm. That seems to be a "shotgun" approach, do you do this routinely? I'm assuming you make a shelf type nut, right? I'll have to try that sometime. I just mentioned the compensating effect of the nut happening within the first three frets because that's where I hear it. Beyond the third or fifth fret I don't notice it but it must keep going up the fretboard, diminishing with each fret.

When talking about a chord being "out of tune" we have to consider the temperament. If you're in "cowboy chord" mode down by the nut, you can tweak the tuning to a great sounding C major chord for example, but the D maj. chord doesn't sound quite as good, the barred F major sounds worse and a D flat major sounds even worse, etc. This effect doesn't necessarily have anything to do with any compensation but rather how you temper the thirds. Keep in mind that were forcing our playing into equal temperament when we use frets and I think players may at times be confusing the "out of tune" of equal temperament vs. the "out of tune" effect of lack of compensation, especially if they're tuning their guitars in ways that don't facilitate equal temperament. Christopher mentions moving the nut forward for the "B" on G chords - this is the effect of temperament as players tune their guitars to chords.

Seems to me that one problem with all this messing around is that you really need a tuner that will give the exact number of cents/ semitone that you are off. I have a Peterson 490 which is a great tuner, but it still only tells you whether you're sharp or flat. And my eyes are getting older and that strobe is hard to look at for extended periods. There must be some software out there that will give you the exact pitch in real time.

Like PT Christopher mentioned the quality of the setup affects matters here. If the nut is as low as you can get away with, with minimal amount of fingerboard relief, low string height and a light touch you may not even notice a problem.

[PTChristopher]

Hiya VJ,

>>> Have you considered the inharmonicity of the string itself,

Yeah. I have mentioned this a few times on the forum mostly to warn people against making adjustments based on notes played above around the 17th fret. Past that (more or less) many strings get the serious "ploink" of inharmonicity overwhelming the root vibration.

>>> I find that if I try to stretch the tuning a tiny bit like a piano tuner might do it seems to make the guitar sound better. But it may be my imagination.

I have tried that, but it requires some pretty convoluted offsets (a la Feiten). I have never come up with an overall pattern that really helped in my opinion. I may just lack talent in this regard.

>>> If I tune every string to an "E" it seems to work better as well - I've been doing that as long as I can remember.

I understand. It sort of builds in a set of offsets for you. It is also subject to some ugliness if you have a bad string - so if things sound bad I always like to wander around the FB and tune to a best fit. Then change the string pretty quickly.

>>> And I was surprised to read the Buzz Feiten guys suggest that as well if you don't have access to a tuner for their special offsets.

I can see how that would work, although I have not thought through any notable downsides there may be.

>>> You say you move the whole nut forward by .5 mm. That seems to be a "shotgun" approach, do you do this routinely?

I agree that it is a shotgun approach and not at all a careful and accurate maneuver.

On the other hand, it does result is better overall low position intonation

>>> do you do this routinely?

I mean that I do it on my own stuff if the opportunity arrises.

I do not luthiate full-time these days. I still have an existing customer base, but most of my work is in other custom woody stuff. Sad to say it simply pays much better.

>>> I'm assuming you make a shelf type nut, right? I'll have to try that sometime.

When I was building way back when, I would just shorten up the FB at the nut end.

Now it is so cheap to have LMI slot the FB that I do not slot myself. (And to think I used to do it by hand - took forever if you wanted to be accurate.)

Funny enough, LMI puts in a zero fret slot centered on the zero position of the FB. So if you cut this slot off entirely (as I assume many do) then you have a half-kerf overall nut compensation. I wonder how often this is used with no thought by the builder?

>>> Beyond the third or fifth fret I don't notice [low position intonation issues] it but it must keep going up the fretboard, diminishing with each fret.

That is my take on it as well. I think Euclid and Newton would agree with you.

>>> When talking about a chord being "out of tune" we have to consider the temperament.

Yeah. I started my first long post last night with tempering, but figured it would go over poorly, so deleted that part.

>>>> If you're in "cowboy chord" mode down by the nut, you can tweak the tuning to a great sounding C major chord for example, but the D maj. chord doesn't sound quite as good, the barred F major sounds worse and a D flat major sounds even worse, etc. This effect doesn't necessarily have anything to do with any compensation but rather how you temper the thirds.

Man, for sure thirds are a killer both for the heavy tempering and the E chord form - especially when played with a light gauge plain G which is very prone to going sharp if you so much as look at it wrong.

>>> I think players may at times be confusing the "out of tune" of equal temperament vs. the "out of tune" effect of lack of compensation, especially if they're tuning their guitars in ways that don't facilitate equal temperament.

Yep. 100% consistent with my experience. I spoke to an ostensibly trained and experienced tech two years ago and he talked about "tempered tuning" as something one does at the tuning machines. I opined that tempering is done when the FB is made. He opined that I smelled like an dead squirrel or something to that effect - which may have been partly true.

>>> If the nut is as low as you can get away with, with minimal amount of fingerboard relief, low string height and a light touch you may not even notice a problem.

Yeah, I think for most players just getting the #u(&ing nut down improves things so much that you can leave it at that.

Thanks for the post VJ.

Chris