Incorrect saddle position?
 

With my new 6-string, the tones are correct up to the 6th fret.
After that, at higher frets, the sound slowly gets a little higher.
I guess the saddle position is probably wrong.
On electric guitars, I can move the little saddles until everything is right.
With acoustics I have to "move" the slot for the bridge inlay
a little further away from the sound hole, fill it and mill it again... right?

The guitar should have been made correctly so that would not be necessary.
What guitar is it.?
If the action is higher than necessary lowering that will reduce the sharpness somewhat.

The guitar may have been built to intonate correctly originally, but top bellying/bridge rotation may have changed it over time.
As previously mentioned, lowering the action can help, lighter string gauge can also help.

It is a bit of a job to move the saddle slot, you can also rework the top of the saddle to move the string contact point and gain a bit.

The point at which the string contacts the saddle can be changed without having to move the saddle itself.

Here's a good article on how to set up your guitar:

https://www.charlestauber.com/luthie...May%202015.pdf

Thank you all very much!
I probably made a mistake when milling the slot in the bridge.
I will fill the slot and then mill it accurately.I guess that will work...

New question:
Comparing the flagiolet values at the 12th fret with the values pressed there,
arises for the pressed ones an increase of approx. 1% more.

Question:
is there any formula or guide that can tell me how much to move the saddle backwards? :confused:

a thought
 

Never did this, but it's cheap: install a sacrificial saddle and make the high point the back edge and see what you get. As for moving the saddle, use a 1/8" thick saddle to give some headroom for adjustment. Gonna' mill anyway, might as well take advantage of the opportunity.

StewMac to the rescue: https://www.stewmac.com/video-and-id...e-saddlematic/

StewMac provides hundreds of tutorials, tool use instructions, kit build instructions, and trade secrets on the website; all are free.

Measure from the nut to the 12th fret. Add about 1/16" to 5/64" to that to get the distance from the 12th fret to the saddle at the first string. I compensate my saddles such that the takeoff point on the first string is at the soundhole side of the saddle. Thus, my measurement for intonation is to that edge of the slot.

Thanks for all of your advices!
I know the saddlematic of Stewmac and made one myself :eek:

I added a bit less than 3mm to the scale.
Slowly I continued with the bridge and the position of the fret inlay.
I filled the old slot with the same ebony as the bridge.
The color will be matched lateron.
Then I made a little device to pull a string in the middle
and to determine the position of the insert.
I struck the flagiolet tone on the 12th fret and then pushed
and slightly shifted the overlay made of ebony and an embedded fret
until everything sounded correct.
http://viento.zenfolio.com/img/s/v-10/p781012784-3.jpg

http://viento.zenfolio.com/img/s/v-10/p579866657-3.jpg

This is obvious, but too much neck relief will shorten your overall scale length and make the high notes creep up. You might take a look at that.

Thanks for your hint!I will keep an eye on that...an ear;)

Why not the 1.6mm to 2.0mm recommended?

Someone had recommended 3mm. Nevertheless I got the mentioned addition.
As I wrote above, I was able to find the optimal position by moving the piece of ebony
with the fret on the bridge.
The rehearsal with the flagiolet tone on the 12th fret also confirmed that.

You fail to mention which string you are adding the 3mm to. My method of measuring to the first string and letting the standard slant of the saddle take care of the rest has served me well.

The geometry of that effect is such that the amount of shortening of the scale is insignificant. The main reason excess relief causes sharp intonation is because of the increase in action at the middle of the neck. Most of the time, the fret spacing is based on a dead straight neck, and compensating the saddle works reasonably well because it becomes a larger percentage of the total fret as you fret higher up on the neck. Example: the distance from the 12th to the 13 fret is exactly half that from the nut to the first fret. So any compensation at the saddle will have twice the effect at the octave as it does at the nut.

I tested the compensation with a tensioned string at the middle between the D and the G string.
The standard slant of the saddle made the rest what I checked afterwards. Now everything seems to sound as it should.
I am satisfied with the result of this whole procedure and like to have it done properly
tho someone (I do not know who) said "there´s no money above the fifth fret"...:lol: