I bought an octave mandola last year and have been playing away on it. The last while, however, the intonation on it hasn't been the best: Whenever E played on the seventh fret of the A string is in tune with the open e-string, the A at fifth fret on the e string is sharper than open A an octave lower. I realise that this may be a product of one or a combination of several things including old strings or a warped neck (unikely as this is a new mandola). I think however that in this case it is down to the positioning of the bridge, which I seem to have moved while replacing the strings. Do any of you mandola/banjo players know of any rule of thumb in positioning the bridge whereby correct intonation is attained?
The best way I’ve found for setting intonation on any fretted instrument is to compare the twelfth fretted note with the twelfth fret harmonic and adjust accordingly. The trick is to use an electronic tuner for the comparison, preferably one with an old fashion meter. This will be significantly more accurate than your ear.
After you do all eight strings, go back and recheck each one.
The octave fretted, ie the 12th fret, is a good start, with a tuner. If the octave is sharp, after tuning the open string, then the bridge needs to be pushed slightly away from the nut. If flat, then towards the nut.Obviously this may vary across the strings, which is why you also have compensated bridges. You mmay have to compromise.
You might also consider taking it to a luthier/repairman for a proper setup. I just had this done to a new octave mandolin, and the difference is huge. Although it did not have any intonation issues before, its playability has significantly increased which means I can and will play it more.
The same luthier did a setup job on a previous OM that had intonation issues, and he made an equally huge difference in making it play easily and accurately all the way up the neck.. Sometimes, it's more than just the proper placement of the bridge.
Remember, several things influence intonation. Assuming that the geometry of the fretboard is correct, the most obvious next variable is the location of the bridge. If, magically, the strings could sit an infinitesimally small distance above the frets and thus not stretch at all in playing, the distances could be optimized by measurement. In practice, the strings (another important factor in intonation) must be stretched to reach the frets. So, some compromise must be achieved between the effect of shortening the string length by fretting it and the additional increase in pitch resulting from stretching it. The amount of stretch isn't the same at all neck locations because the string isn't parallel to the fretboard. It's higher above the frets up the neck than down, and thus gets more of a stretch in some locations. (As an aside, a high nut can necessitate excessive string stretch when fretting the first fret and that may be wehre intonation is noticeably off.) Bridge location optimization is both a compromise (i.e., an attempt to minimize intonation errors on average) and is specific to a particular gauge of string and a particular bridge height (if adjustable).
With a very nicely set up instrument, using the 12th fret works well in practice.
Of necessity, if the bridge is not compensated, the different gauges of string produce an unavoidable inconsistency of intonation across string courses. A simple way of offsetting this is to tip the bridge so that it isn't parallel to the nut. Most often, the bass end is moved farther from the nut by a modest amount. This gives each string a slightly different scale length to offset the differences in string gauge (and thus stretch during fretting). A more precise fix is to fully compensate the bridge by shifting different portions of its length either toward or away from the nut to achieve optimal compensation for that particular string.
As an instrument goes through the inevitable changes that occur with time (such as the top raising or lowering slightly from the constant string tension, humidity changes, etc.), the initial compromises may need further adjustment. On some instruments where the neck has bowed forward, for example, the string stretches at some neck locations may become considerable and thus the strings are sharpened during fretting more than was originally the case. As a result, getting intonation perfect at the 12th fret may make it way off at some other location. On such instruments, when neck straightening isn't an option, it may be better to optimize bridge location for, say, the 7th fret rather than the 12th. This is so because the lower frets are used more and the distortion on frets 1-6 will be less if intonation is optimized for fret 7 than if it's optimized for fret 12.
So, if intonation is off for some strings, the first question to ask is whether the bridge height has been changed. If so, and if the new height is to be retained, then other factors will have to be adjusted to offset the change (see recommendations for different string gauges).
Next ask if the string gauges have been changed. If so, that's another likely explanation for intonation errors. If the new string gauges are preferred, then some adjustments to the bridge will be needed to optimize for the new gauge. (If the strings are the same gauge but are very old, their physical properties may have changed through use to make them less elastic and pitch changes resulting from fretting may have changed as well. New strings should be the fix here.)
If the strings are relatively fresh and of the same gauge as before, then a shift in bridge position is the next thing to assess as a cause of poor intonation. This requires some fiddling. Remember that a shift from side-to-side also affects string tension and thus intonation. The outermost strings are usually displaced laterally by the bridge,. If the bridge shifts sideways, one of those pairs of outer strings get straighter while the other gets less straight. That changes tension and intonation. So, check that the bridge is (1) centered properly left-to-right, (2) the optimal distance from the nut as determined by the 12th fret harmonic/fretted-note method, and (3) if uncompensated, is tipped so as to yield the best intonation compromise across the strings. (If the bridge is a two-part adjustable bridge, make sure that the top part wasn't removed at some point and then put on backwards -- or, perhaps the whole bridge was removed and put back on backwards.) If things are still way off, it might be that fret wear is causing certain notes to fret incorrectly, giving a sharp or flat note. A fret dressing will fix that.
If none of this yields intonation as accurate as it once was, then the neck may have changed (e.g., warped or neck joint slippage) or the top may have sunken (e.g., because of a loose brace). these are serious problems that require professional attention.
I hope that I haven't merely stated the obvious and that some of this lengthy post will be of use to someone.
Nice encyclopedic response, devellis. Optimizing at the seventh fret seems like a good idea, but what would the procedure be? I’m having trouble seeing how you would do it using harmonics.
Devellis said more than I had the time to - SO arrived hotfoot from work to go to a showing of "The Wind That Shakes The Barley" with director present for Q & A afterwards - that was nice.........
Optimising at the seventh fret - well it just means getting the intonation correct at the seventh fret if you can't get it right all the way up the fingerboard. You definitely need ( to beg, steal, or borrow ) a digital tuner for this process. A visit to a luthier might also help if you're not expert in working through these problems.
You usually find that the bridge leaves a pale shadow on the soundboard of all but the newest instruments, to show where it's been, which might be a help. You could even just measure - the nut to twelth fret measurement should be almost exactly the same, perhaps a millimetre less, as the twelth fret to bridge, for the top strings, and the bass scale should be slightly longer, which is why guitars have this sloping saddle arrangement on the bridge, when you look directly down at them. On the simpler mando-family instruments this is achieved by the whole bridge being set at a slight angle, on the better instruments there are individual corrections carved into the bridge-top for each pair of strings as well.
Intonation is a complicated process, as devellis implies, but I hope between us we've given some simple tips.
PS I only change one string at a time when re-stringing, it avoids various problems, including re-tensioning the whole instrument, and bridge-slippage.
Also, a new set of strings might solve many problems.
I have tried optimizing intonation at the 7th fret. I would not use harmonics for this, though. I would tune the open string with an electronic tuner - to E, say - then use the tuner to check the tuning of the A at the 7th fret, and shift the bridge accordingly (remembering to retune the open string every time the bridge is moved).
The harmonic at (or near) the 7th fret is 3 times the fundamental frequency, or an octave-and-a-fifth above the open string note. However, this is a untempered interval, while the note sounded by the string when *fretted* at the 7th fret should be a tempered fifth (slightly flatter than the untempered fifth). So, an instrument whose intonation is set up using harmonics - with the exception of the octave harmonic - will not note true.
Octave mandolas are always a bit tricky. If you can afford the time and (possibly) money involved, ask your local competent luthier to set the instrument up, then before playing, mark the bridge position with a couple of small spots of felt tip pen. Stick to the same string gauge and always check bridge position when changing strings.
Others have pretty well covered the 7th fret optimization. Just to reiterate briefly, position the bridge wherever you can get the best compromise between a properly-tuned open string and correct pitch for that string when fretted at the 7th fret. You may be a bit flat below that fret and a bit sharp above, but you'll be close pretty much throughout the "working" range of the fingerboard if the neck isn't too bad.
Intonation on Mandolas
Intonation on Mandolas
I bought an octave mandola last year and have been playing away on it. The last while, however, the intonation on it hasn't been the best: Whenever E played on the seventh fret of the A string is in tune with the open e-string, the A at fifth fret on the e string is sharper than open A an octave lower. I realise that this may be a product of one or a combination of several things including old strings or a warped neck (unikely as this is a new mandola). I think however that in this case it is down to the positioning of the bridge, which I seem to have moved while replacing the strings. Do any of you mandola/banjo players know of any rule of thumb in positioning the bridge whereby correct intonation is attained?
# Posted on July 11th 2006 by An Dearg
Re: Intonation on Mandolas
The best way I’ve found for setting intonation on any fretted instrument is to compare the twelfth fretted note with the twelfth fret harmonic and adjust accordingly. The trick is to use an electronic tuner for the comparison, preferably one with an old fashion meter. This will be significantly more accurate than your ear.
After you do all eight strings, go back and recheck each one.
# Posted on July 11th 2006 by Bob himself
Re: Intonation on Mandolas
The octave fretted, ie the 12th fret, is a good start, with a tuner. If the octave is sharp, after tuning the open string, then the bridge needs to be pushed slightly away from the nut. If flat, then towards the nut.Obviously this may vary across the strings, which is why you also have compensated bridges. You mmay have to compromise.
# Posted on July 11th 2006 by Guernsey Pete
Re: Intonation on Mandolas
You might also consider taking it to a luthier/repairman for a proper setup. I just had this done to a new octave mandolin, and the difference is huge. Although it did not have any intonation issues before, its playability has significantly increased which means I can and will play it more.
The same luthier did a setup job on a previous OM that had intonation issues, and he made an equally huge difference in making it play easily and accurately all the way up the neck.. Sometimes, it's more than just the proper placement of the bridge.
# Posted on July 11th 2006 by Audeamus
Re: Intonation on Mandolas
Remember, several things influence intonation. Assuming that the geometry of the fretboard is correct, the most obvious next variable is the location of the bridge. If, magically, the strings could sit an infinitesimally small distance above the frets and thus not stretch at all in playing, the distances could be optimized by measurement. In practice, the strings (another important factor in intonation) must be stretched to reach the frets. So, some compromise must be achieved between the effect of shortening the string length by fretting it and the additional increase in pitch resulting from stretching it. The amount of stretch isn't the same at all neck locations because the string isn't parallel to the fretboard. It's higher above the frets up the neck than down, and thus gets more of a stretch in some locations. (As an aside, a high nut can necessitate excessive string stretch when fretting the first fret and that may be wehre intonation is noticeably off.) Bridge location optimization is both a compromise (i.e., an attempt to minimize intonation errors on average) and is specific to a particular gauge of string and a particular bridge height (if adjustable).
With a very nicely set up instrument, using the 12th fret works well in practice.
Of necessity, if the bridge is not compensated, the different gauges of string produce an unavoidable inconsistency of intonation across string courses. A simple way of offsetting this is to tip the bridge so that it isn't parallel to the nut. Most often, the bass end is moved farther from the nut by a modest amount. This gives each string a slightly different scale length to offset the differences in string gauge (and thus stretch during fretting). A more precise fix is to fully compensate the bridge by shifting different portions of its length either toward or away from the nut to achieve optimal compensation for that particular string.
As an instrument goes through the inevitable changes that occur with time (such as the top raising or lowering slightly from the constant string tension, humidity changes, etc.), the initial compromises may need further adjustment. On some instruments where the neck has bowed forward, for example, the string stretches at some neck locations may become considerable and thus the strings are sharpened during fretting more than was originally the case. As a result, getting intonation perfect at the 12th fret may make it way off at some other location. On such instruments, when neck straightening isn't an option, it may be better to optimize bridge location for, say, the 7th fret rather than the 12th. This is so because the lower frets are used more and the distortion on frets 1-6 will be less if intonation is optimized for fret 7 than if it's optimized for fret 12.
So, if intonation is off for some strings, the first question to ask is whether the bridge height has been changed. If so, and if the new height is to be retained, then other factors will have to be adjusted to offset the change (see recommendations for different string gauges).
Next ask if the string gauges have been changed. If so, that's another likely explanation for intonation errors. If the new string gauges are preferred, then some adjustments to the bridge will be needed to optimize for the new gauge. (If the strings are the same gauge but are very old, their physical properties may have changed through use to make them less elastic and pitch changes resulting from fretting may have changed as well. New strings should be the fix here.)
If the strings are relatively fresh and of the same gauge as before, then a shift in bridge position is the next thing to assess as a cause of poor intonation. This requires some fiddling. Remember that a shift from side-to-side also affects string tension and thus intonation. The outermost strings are usually displaced laterally by the bridge,. If the bridge shifts sideways, one of those pairs of outer strings get straighter while the other gets less straight. That changes tension and intonation. So, check that the bridge is (1) centered properly left-to-right, (2) the optimal distance from the nut as determined by the 12th fret harmonic/fretted-note method, and (3) if uncompensated, is tipped so as to yield the best intonation compromise across the strings. (If the bridge is a two-part adjustable bridge, make sure that the top part wasn't removed at some point and then put on backwards -- or, perhaps the whole bridge was removed and put back on backwards.) If things are still way off, it might be that fret wear is causing certain notes to fret incorrectly, giving a sharp or flat note. A fret dressing will fix that.
If none of this yields intonation as accurate as it once was, then the neck may have changed (e.g., warped or neck joint slippage) or the top may have sunken (e.g., because of a loose brace). these are serious problems that require professional attention.
I hope that I haven't merely stated the obvious and that some of this lengthy post will be of use to someone.
# Posted on July 11th 2006 by devellis
Re: Intonation on Mandolas
Nice encyclopedic response, devellis. Optimizing at the seventh fret seems like a good idea, but what would the procedure be? I’m having trouble seeing how you would do it using harmonics.
# Posted on July 11th 2006 by Bob himself
Re: Intonation on Mandolas
Devellis said more than I had the time to - SO arrived hotfoot from work to go to a showing of "The Wind That Shakes The Barley" with director present for Q & A afterwards - that was nice.........
Optimising at the seventh fret - well it just means getting the intonation correct at the seventh fret if you can't get it right all the way up the fingerboard. You definitely need ( to beg, steal, or borrow ) a digital tuner for this process. A visit to a luthier might also help if you're not expert in working through these problems.
You usually find that the bridge leaves a pale shadow on the soundboard of all but the newest instruments, to show where it's been, which might be a help. You could even just measure - the nut to twelth fret measurement should be almost exactly the same, perhaps a millimetre less, as the twelth fret to bridge, for the top strings, and the bass scale should be slightly longer, which is why guitars have this sloping saddle arrangement on the bridge, when you look directly down at them. On the simpler mando-family instruments this is achieved by the whole bridge being set at a slight angle, on the better instruments there are individual corrections carved into the bridge-top for each pair of strings as well.
Intonation is a complicated process, as devellis implies, but I hope between us we've given some simple tips.
# Posted on July 12th 2006 by Guernsey Pete
Re: Intonation on Mandolas
PS I only change one string at a time when re-stringing, it avoids various problems, including re-tensioning the whole instrument, and bridge-slippage.
Also, a new set of strings might solve many problems.
# Posted on July 12th 2006 by Guernsey Pete
7th Fret
I have tried optimizing intonation at the 7th fret. I would not use harmonics for this, though. I would tune the open string with an electronic tuner - to E, say - then use the tuner to check the tuning of the A at the 7th fret, and shift the bridge accordingly (remembering to retune the open string every time the bridge is moved).
The harmonic at (or near) the 7th fret is 3 times the fundamental frequency, or an octave-and-a-fifth above the open string note. However, this is a untempered interval, while the note sounded by the string when *fretted* at the 7th fret should be a tempered fifth (slightly flatter than the untempered fifth). So, an instrument whose intonation is set up using harmonics - with the exception of the octave harmonic - will not note true.
# Posted on July 12th 2006 by CreadurMawnOrganig
Re: Intonation on Mandolas
Heard Tim O'Brien say once that Mandolin is an Italian word for "Out of tune"!
# Posted on July 12th 2006 by woops
Re: Intonation on Mandolas
Octave mandolas are always a bit tricky. If you can afford the time and (possibly) money involved, ask your local competent luthier to set the instrument up, then before playing, mark the bridge position with a couple of small spots of felt tip pen. Stick to the same string gauge and always check bridge position when changing strings.
# Posted on July 12th 2006 by millionyears_bc
Re: Intonation on Mandolas
Others have pretty well covered the 7th fret optimization. Just to reiterate briefly, position the bridge wherever you can get the best compromise between a properly-tuned open string and correct pitch for that string when fretted at the 7th fret. You may be a bit flat below that fret and a bit sharp above, but you'll be close pretty much throughout the "working" range of the fingerboard if the neck isn't too bad.
# Posted on July 12th 2006 by devellis