Floating Bridge Angle - Intonation with 11/49 string set

[xuoham]

Hi,

Today i tried some light gauge 11/49 round wound D'addario on my Ibanez AF105 and in order to get a proper intonation i ended up with my rosewood bridge in a diagonal that is reversed: shorter scale for the 6th string than for the 1st.

Is this normal for a light gauge ? That may be a stupid question but i am quite surprised. For example i already tried some super light strings on my flat top acoustic, just as an experiment, and the intonation was not so bad, though of course i could not move the bridge around.

So, " \ " instead of " / " , .... what ?

Thanx !

[PTChristopher]

The angle you now have is extremely unlikely - all but impossible really.

I suggest checking each strings intonation at several fret positions between the 7th and 17th frets to see if you maybe have either a defective single string or possibly some minor pilot error while setting up the bridge.

Chris

[mr. beaumont]

Seems really weird...something's amiss.

[xuoham]

Thanks for the help guys

OK, on one hand it confirms that it's weird, on the other hand i checked better and since the rosewood bridge is compensated, i actually have, not a reverse diagonal, but a really perpendicular angle.
If you check the photo the intersection point between the strings and the bridge is perpendicular.
Is it still weird, considering it's not the regular 12 or 13 gauge ?

[PTChristopher]

1. It has nothing whatsoever to do with the string gauge being 11 to 49 vs. 12 or 13 to somethingorother.

2. Despite the slanted bridge saddle, the angle is none the less highly unlikely to be a best fit bridge compensation for a well set up guitar.

Did you do any of the checks suggested above with results to discuss? If I may ask.

Chris

[Patrick2]

[quote=xuoham;270174]Thanks for the help guys

OK, on one hand it confirms that it's weird, on the other hand

i checked better and since the rosewood bridge is compensated, i actually have, not a reverse diagonal, but a really perpendicular angle.
If you check the photo the intersection point between the strings and the bridge is perpendicular.

The compensation shaped into the saddle is there so that you don't need to "dramatically" tilt you bridge base-assembly to the \ possition. The compensation allows you to keep your entire base-saddle perpendicular . . so it looks less "tilted" and less goofy to dick head collectors like myself who care more about aesthetics than we do about intonation.

[xuoham]

1. It has nothing whatsoever to do with the string gauge being 11 to 49 vs. 12 or 13 to somethingorother.

2. Despite the slanted bridge saddle, the angle is none the less highly unlikely to be a best fit bridge compensation for a well set up guitar.

Did you do any of the checks suggested above with results to discuss? If I may ask.

Chris

I forgot to check at 17th fret !

Intonation is spot on until 12 th fret, then is starts to get flat and it is very bad at 17th fret, for all the six strings.

What can this be?

I don't know much but the neck seems OK.
Relief seems ok, like half a mm at 8th fret and the action at the 12th fret is 2.5mm for 6th string, 2mm for 1st string.

[xuoham]

Ah by the way, PTChristopher, what do you mean by "minor pilot error" ?
Thnx

[PTChristopher]

Hi Xuo,

>>> what do you mean by "minor pilot error"

I sometimes make human mistakes that I discover on careful review, so I considered this a possible part of your experience.

In my opinion the principles at work here are simple enough, but it could be a very long process to get through this problem and solution if we are taking quite small steps to sort this out.

Can you bring the guitar to a luthier/tech and get it set up?

>>>Intonation is spot on until 12 th fret, then is starts to get flat and it is >>> very bad at 17th fret, for all the six strings.

>>>What can this be?

This can be a number of things, all identifiable, adjustable, and fixable.

But if we need to go through each step very slowly and with some minor mis-understandings at each step, this may not be as rewarding a process as a simple trip to a reasonably competent local pro.

I have never been to Okinawa, but in Paris there are plenty of places to get your set up done, and a few regular members here to suggest their favorite local tech.

Chris

[xuoham]

Thanks a lot Chris,

Yeah, i think it's inevitable i pay a visit to my tech. (Yes, fortunately there is a good one here in OKinawa !)
I got this guitar for as month now, and i guess this matter is beyond my understanding.

Really thank you for your time !!

[Jabberwocky]

I suggest you remove the felt pad under the treble side of your bridge base and re-intonate. The pad could be just thick enough to make the base cant forward slightly or slip when you tune up. This makes the intonation appear sharp. And hence you push back the base until it appears to intonate correctly at the 12th fret. But now the string is in truth too long and it is flat past the 12th.

Your bass side is not affected that badly because it is planted comparatively solidly against the top of the guitar.

In short, the treble side of the bridge base is canting slightly or slipping due to the soft felt pad. Remove the pad. Intonate. And then replace the felt pad when the intonation is right. This means marking the spot for the bridge base and retuning. What fun!

*You could use a grease pencil and draw an outline for the bridge base on the guitar top when it is satisfactorily intonated.
** Measure the 1st string from the rear edge of the nut to the saddle break point. I bet it measures longer than 24.75" as you have it now. I have the AF105NT and relative to my own bridge placement, I can tell that your treble side is too long. I eyeball as a reference point the rear edge of your humbucker mounting ring.
*** Or you could go back to using a TOM bridge.

****I could well end up with omelette on my face if it turns out to be something else when the morning breaks.

[SearchForMeaning]

This can be a number of things, all identifiable, adjustable, and fixable.

But if we need to go through each step very slowly and with some minor mis-understandings at each step, this may not be as rewarding a process as a simple trip to a reasonably competent local pro.

Chris's advice is right, or we could go through step by step here as a learning experience.
A good even intonation is based on the assumption that the fretboard is good and even. How's the neck? Did you adjust the truss rod and put it straight first? It seems that there's a bow, that'll put your lower frets at odds with the upper frets if it's pronounced enough. If the action at the nut is high, this will give you more string deformity on the lower frets. If the neck has begun to go out due to a neck block problem (unlikely but I have seen it) that'll give you different compensation once the neck leaves the body joint. So you see, there are things that should be right when things are right, so to say.
And what's that thing under the bridge leg? I set up guitars before they went to dealers and I always told my bosses "Let me take that stupid foam out, they'll never do it on the other end (at the store)" but they did it for shipping and to protect the finish... and introduced a defeating feature into the set up of the instrument. Oh well.

What's the intonation at the 12th (midpoint)? That's your gauge point, traditionally. What's your action? Do you have a heavy or light touch? Good for you for doing this yourself though, you can learn a lot.

[xuoham]

I suggest you remove the felt pad under the treble side of your bridge base and re-intonate. The pad could be just thick enough to make the base cant forward slightly or slip when you tune up. This makes the intonation appear sharp. And hence you push back the base until it appears to intonate correctly at the 12th fret. But now the string is in truth too long and it is flat past the 12th.

Your bass side is not affected that badly because it is planted comparatively solidly against the top of the guitar.

In short, the treble side of the bridge base is canting slightly or slipping due to the soft felt pad. Remove the pad. Intonate. And then replace the felt pad when the intonation is right. This means marking the spot for the bridge base and retuning. What fun!

*You could use a grease pencil and draw an outline for the bridge base on the guitar top when it is satisfactorily intonated.
** Measure the 1st string from the rear edge of the nut to the saddle break point. I bet it measures longer than 24.75" as you have it now. I have the AF105NT and relative to my own bridge placement, I can tell that your treble side is too long. I eyeball as a reference point the rear edge of your humbucker mounting ring.
*** Or you could go back to using a TOM bridge.

****I could well end up with omelette on my face if it turns out to be something else when the morning breaks.

Thanks a lot for the witty help
The problem was here before the felt, actually since i use this rosewood bridge instead of the TOM.
Yes my 1st string's scale is too long ! I was actually wondering what is the reference point when one talks about scale since it is different for each string.

[xuoham]

....
And what's that thing under the bridge leg? I set up guitars before they went to dealers and I always told my bosses "Let me take that stupid foam out, they'll never do it on the other end (at the store)" but they did it for shipping and to protect the finish... and introduced a defeating feature into the set up of the instrument. Oh well.

What's the intonation at the 12th (midpoint)? That's your gauge point, traditionally. What's your action? Do you have a heavy or light touch? Good for you for doing this yourself though, you can learn a lot.

Thank you ! Ah i see, LOL, no, i took out the foam of course
This is a piece of felt that is here on purpose, to tame some harshness because i have a transducer under the top. The problem was here before the felt.
The intonation is spot on at 12th fret, and that's in order to get the right intonation at this 12th fret that i had to tilt the bridge, absolutely forgetting to check intonation at the 19th fret
The action is as said above, 2.5mm and 2mm, i have a rather light touch, and i haven't touched the truss rod yet, as i have 1/2 mm clearance at 8th fret, i thought this was perfect.
Indeed, maybe i should get the neck straight first !
Thanks for your great advice !
And you're right, i feel i'm learning a lot!

[PTChristopher]

Indeed the bridge saddle will always be placed slightly farther than the actual scale length.

To find the actual scale length (not that it matters much), measure from the front edge of the nut to the CENTER of the 12th fret along the D or G string. This is 1/2 of the scale length.

To set the saddle in a good starting place for fine adjustment, place the high E about 1,5mm past the measured scale length, and the low E about 4,5mm back.

There is no point in making a fine adjustment of this until you have in chronological order:

1. The nut height down where it needs to be (see the frets.com explanation of nut height, and absolutely ignore the remarkably misguided Stewmac descriptions).

2. A rough setting of the action height at the bridge.

3. The neck relief where you like it. When in doubt set it for around the thickness of your B string then adjust from there based on fret noise in low positions vs. high positions at your preferred action height.

4. Fine adjustment of action height.

5. And only now can you fine tune the saddle position. For better results with a wooden saddle ignore the E strings and the 12th fret harmonics (gasp!, yes indeed). Tune all the strings, then play a number (like 6 or more) of different fretted notes on the A and B strings between the 7th fret and the 17th fret. Adjust the saddle for a best fit of a number of notes not just one note at the 12th.

It works remarkably well and provides a fast and very fine "best fit" amongst the variables involved.

Chris

[PTChristopher]

The felt has no bearing on your odd problem. It is an unusual solution to the transducer scratchy sound, and carries what many consider to be some unfortunate tone artifacts, but it will not prevent a very good bridge compensation set up.

All in my opinion.

Chris

[xuoham]

Indeed the bridge saddle will always be placed slightly farther than the actual scale length.

To find the actual scale length (not that it matters much), measure from the front edge of the nut to the CENTER of the 12th fret along the D or G string. This is 1/2 of the scale length.

To set the saddle in a good starting place for fine adjustment, place the high E about 1,5mm past the measured scale length, and the low E about 4,5mm back.

There is no point in making a fine adjustment of this until you have in chronological order:

1. The nut height down where it needs to be (see the frets.com explanation of nut height, and absolutely ignore the remarkably misguided Stewmac descriptions).

2. A rough setting of the action height at the bridge.

3. The neck relief where you like it. When in doubt set it for around the thickness of your B string then adjust from there based on fret noise in low positions vs. high positions at your preferred action height.

4. Fine adjustment of action height.

5. And only now can you fine tune the saddle position. For better results with a wooden saddle ignore the E strings and the 12th fret harmonics (gasp!, yes indeed). Tune all the strings, then play a number (like 6 or more) of different fretted notes on the A and B strings between the 7th fret and the 17th fret. Adjust the saddle for a best fit of a number of notes not just one note at the 12th.

It works remarkably well and provides a fast and very fine "best fit" amongst the variables involved.

Chris

Nice tip !
I guess that anyway a good guitar intonation is made of compromises and that you can't have your tuner display a full match at any fret, can you ?
Will try, seems like such a better way than the very primitive method i was using.
Ah, i love guitar forums ...

[xuoham]

The felt has no bearing on your odd problem. It is an unusual solution to the transducer scratchy sound, and carries what many consider to be some unfortunate tone artifacts, but it will not prevent a very good bridge compensation set up.

All in my opinion.

Chris

I was sure this felt had no relation, since i can lower or raise the floating bridge at will.

"... what many consider to be some unfortunate tone artifacts"

Yes, theoretically it's very bad, but it works, and to my surprise the mag PU didn't lose any of its bite, because still half of the bridge is in direct contact.
And anyway, even piano hammers have felt, don't they ?
But this is o.t. anyway

[PTChristopher]

>>> I guess that anyway a good guitar intonation is made of compromises and that you can't have your tuner display a full match at any fret, can you ?

In my experience this is correct. There are a number of reasons for this, but maybe beyond the scope of this thread.

But yes, if you get the principle that you are going for a "best fit", this helps a great deal to make best-fit choices that suit your playing style.

Simply making the 12th fret E note be "perfect" on a tuner includes many compromises and potential significant errors.

So yes, in my opinion it is FAR better to understand that the goal is to match the "best-fit" to the guitar and player in question, then proceed by checking many notes in the range most affected by bridge compensation - between the 7th and 17th.

Below the 7th, the nut position and height has far more effect than the bridge compensation. Above the 17th, most strings are now exhibiting significant inharmonicity, which is unaffected by bridge compensation.

Etc.,,,

Chris

[xuoham]

Wow, i really learned a good lesson today

[PTChristopher]

This is all in my opinion and experience. You may find very different views from others that will be very helpful.

Well, except for the Stewmac "info" on nut slot height - that is to be avoided in all cases.

Best luck getting your guitar to play its best, which should be quite good in fact on this very nicely made box.

Chris

[Patrick2]

[quote=PTChristopher;270242]>>> I guess that anyway a good guitar intonation is made of compromises and that you can't have your tuner display a full match at any fret, can you ?

In my experience this is correct. There are a number of reasons for this, but maybe beyond the scope of this thread.

But yes, if you get the principle that you are going for a "best fit", this helps a great deal to make best-fit choices that suit your playing style.

Simply making the 12th fret E note be "perfect" on a tuner includes many compromises and potential significant errors.

So yes, in my opinion it is FAR better to understand that the goal is to match the "best-fit" to the guitar and player in question, then proceed by checking many notes in the range most affected by bridge compensation - between the 7th and 17th.

Below the 7th, the nut position and height has far more effect than the bridge compensation. Above the 17th, most strings are now exhibiting significant

inharmonicity,

Really??? Alphabet Soup for breakfast???? Holy shamoly!!! Now you've got me running to consult ol' Dan'l Webster . . . . .

[xuoham]

This is all in my opinion and experience. You may find very different views from others that will be very helpful.

Well, except for the Stewmac "info" on nut slot height - that is to be avoided in all cases.

Best luck getting your guitar to play its best, which should be quite good in fact on this very nicely made box.

Chris

Thank you for you kindness.

Best,

Paul

[PTChristopher]

[Inharmonicity]

>>> Really??? Alphabet Soup for breakfast???? Holy shamoly!!! Now you've got me running to consult ol' Dan'l Webster . . . . .

Is that Daniel or Merriam Webster?

Inharmonicity is the reason pianos are stretch tuned, with the high notes raised in pitch and the low notes lowered in pitch.

In briefs (or boxers):

Strings are not perfectly flexible.

So a 25" length of a given string at a given mass and tension will not vibrate at exactly the calculated pitch. The stiffness of the string at the ends makes the effective length slightly shorter.

Harmonics involve vibrations of a string that are shorter than the full vibrating length, and the stiffness plays a larger role as the vibrations get shorter. The stiff area becomes a larger % of the total length of a vibration.

Soooooo,...

When you play the low E at the 19th fret it goes "ploink" with very sharp harmonics - not "in tune" with the primary note. This is due to a number of things, but by far the big one is string stiffness on this fat short string. Inharmonicity.

On a piano if you tune "middle C" to pitch. The upper harmonics will in fact be sharp of the expected intervals - and out of tune with a note played way up the keyboard. So the higher notes are 'stretched' to be more in tune with the harmonics they may encounter with played along with the mid-keyboard notes.

Low piano notes are dropped a little so they harmonics do not sound awful with mid-keyboard notes. Inharmonicity and stretch tuning. On a piano, "perfect intonation" would sound awful. The intonation is intentionally altered as you move out to the ends of the keyboard.

On a guitar, the practical effect is just sharp harmonics when playing way up the FB - so don't use notes above the 17th fret (arguably even past the 15th on many stiffer strings) for any intonation tests.

Blah, blah, blah,...

Chris

[Patrick2]

[Inharmonicity]

>>> Really??? Alphabet Soup for breakfast???? Holy shamoly!!! Now you've got me running to consult ol' Dan'l Webster . . . . .

Is that Daniel or Merriam Webster?

Inharmonicity is the reason pianos are stretch tuned, with the high notes raised in pitch and the low notes lowered in pitch.

In briefs (or boxers):

Strings are not perfectly flexible.

So a 25" length of a given string at a given mass and tension will not vibrate at exactly the calculated pitch. The stiffness of the string at the ends makes the effective length slightly shorter.

Harmonics involve vibrations of a string that are shorter than the full vibrating length, and the stiffness plays a larger role as the vibrations get shorter. The stiff area becomes a larger % of the total length of a vibration.

Soooooo,...

When you play the low E at the 19th fret it goes "ploink" with very sharp harmonics - not "in tune" with the primary note. This is due to a number of things, but by far the big one is string stiffness on this fat short string. Inharmonicity.

On a piano if you tune "middle C" to pitch. The upper harmonics will in fact be sharp of the expected intervals - and out of tune with a note played way up the keyboard. So the higher notes are 'stretched' to be more in tune with the harmonics they may encounter with played along with the mid-keyboard notes.

Low piano notes are dropped a little so they harmonics do not sound awful with mid-keyboard notes. Inharmonicity and stretch tuning. On a piano, "perfect intonation" would sound awful. The intonation is intentionally altered as you move out to the ends of the keyboard.

On a guitar, the practical effect is just sharp harmonics when playing way up the FB - so don't use notes above the 17th fret (arguably even past the 15th on many stiffer strings) for any intonation tests.

Blah, blah, blah,...

Chris

WOW!! Who knew?? So then, inharmonics . . . is totally different then enharmonics.