compensated bridges??

[Willie]

Has anyone given any thought to that if someone were to figure out string gauges a mandolin bridge could be built without the compensated flutes...I believe the older F-2`s and F-4`s didn`t have a compensated bridge so why have them on the F-5`s and later styles? Maybe I am missing something but I did build one bridge saddle with a straight across design and it noted perfect all the way up the neck and I used a regular set of GHS strings...Any thoughts on this.....Willie

[Paul Hostetter]

I think you are missing something. If you were to string a mandolin with 8 strings of the same gauge, all tuned to the same pitch, you could dispense with a compensated saddle on the bridge. It doesn't sound like fun to me.

Though there may have been a few, I don't recall ever seeing a Gibson mandolin in the post-Orville era that didn't have a compensated bridge. An A-4 from 1917:

[MikeEdgerton]

....If you were to string a mandolin with 8 strings of the same gauge, all tuned to the same pitch, you could dispense with a compensated saddle on the bridge...

I was just thinking the same thing.

[Rick Turner]

Going back a bit, vintage intonation was...well, pretty iffy. "Golden Era" guitars all need a bit of a tweak unless you're strictly playing cowboy chords, for instance.

The issues are tension and the actual stiffness for each string. Stiffer strings need to be compensated flatter for the harmonics to be closer in tune.

[Paul Hostetter]

Going back a bit, vintage intonation was...well, pretty iffy. "Golden Era" guitars all need a bit of a tweak unless you're strictly playing cowboy chords, for instance.

Amen, some really needed help. Here's 1930 OM-18 with a belly bridge and a nearly-parallel saddle. Even a simple G chord never sounded right on these babies. (Another below.)



Fortunately it got better, though it took Martin decades before it got it right.

But waitaminnit - weren't we talking about mandolins?

[David Collins]

Paul and Rick are quite right that instruments of the past are not quite fit to be held as a benchmark of good intonation. From saddle shapes and compensation to quirky fret spacings, there have always been lots of intonation issues. How much you notice them depends on your discretion, and the context in which notes are played. If the intonation of historical instruments demonstrate anything it is the ability of musicians to cope with intonation issues and/or work around them, but certainly not any lack thereof.

Or in the words of General Perronet Thompson -

"if the instrument maintains its ground in practice at all, it is in consequence of its convenience, of fashion, and above all, of the badness of people's ears."

This was written 180 years ago in reference to guitars, but inspired by problems which carry through equally to the mandolin. There will always be intonation issues, and the compensated bridge or saddle is simply a necessary tool to lessen their significance a bit more than the straight alternative.

[Big Joe]

In addition to that, the scale we use today is A=440hz. That was not the case in the past, and the intonation points would be slightly different for that tuning. I don't know of any instrument that will play in tune with itself with a straight across saddle if it uses different size and guage strings for each of the different strings. Even most of the intonated saddles are pretty weak. We call it "tempered tuning", which basically means it won't play in tune everywhere, but it's close enough that if we don't pay real close attention, we can live with it. There are a couple things fairly recent that help this issue. One is the Buzz Feinten nut tuning system. The other is the Earvana nut system. They compensate the scale at the nut and make correct adjustments at the saddle for the string guage and scale length being used. I have an Earvana on one of my guitars and it really makes a difference. We have recently begun installing these and the ones we have installed have really amazed the customers.

Intonation is always an issue one is dealing with in the instrument business. In Nashville the pickers can be extremely fussy about their setups and intonation. We deal with numerous issues dealing with intonation all the time on nearly any kind of instrument you can imagine. I can say that after doing thousands of setups over many years that a straight across saddle has never been functional that I can recall.

[Willie]

at one time I owned a 1919 Gibson F-2 three point and it was suppose to have been all original and it had a bridge with out any compensation, I will say this, I couldn`t stand to play that mandolin because it noted off, I also had a teens Lyon and Healy and it also had a non compensated bridge..I understand your points and I thank you for the explanations, I just thought if an A string and the G string was a different gauge they wouldn`t need to be compensated at the bridge and bridges would be lot easier to make.....Thanks for the info, it clears it up for me....Willie

[Ivan Kelsall]

Un-compensated bridges are very much normal on Banjos.Compensated Banjo bridges are available,but usually they're such huge chunks of wood,that they destroy the Banjo 'tone' & can sound really thunky. It causes a lot of problems,believe me. Geoff Stelling tries to tackle the problem by having a compensated nut,in which the varying strings,touch the nut at different distances from the bridge,it helps but it's not perfect. The ONLY instrument that i have that IS in (almost) perfect tune,is my Tokai 'Tele' electric Guitar,which has adjustable bridge saddles.They can be adjusted to obtain a perfect octave on each string & then adjusted again to allow 'across the fingerboard' tuning as accurately as it can be - so even then it a slight compromise, as fret positions in themselves are a compromise,
Ivan

[Paul Hostetter]

For mandolins:



And for banjos, a compensated bridge that does not weigh more:

[David Collins]

Something else few people realize is just how much fret spacing itself has changed over the years, and across different makers. On Gibson mandolins, a 1908 mandolin will have very different spacing from a 1918, which will be different from a 1928, which changed again by 1948, all of which are quite different from a 2008 mandolin. This has nothing to do with the open tuning pitch, as ratio of open to fretted lengths will be the same regardless of what reference pitch you tune to. Nor does it deserve to fall in to the category of different temperaments, as it is not an attempt to tune each note to favor a particular key or compromise among many. Most of the historical spacings I would say are much less noble than this, and feel they would be better described as mistakes, or well intended but misguided attempts toward an ideal spacing.

None of this relates directly to compensated bridges, but effects intonation across the board just the same. A compensated bridge is primarily an attempt to compensate for the different stiffnesses of strings which create different imperfect nodes at the ends and between harmonics, as well as varying changes in length and tension as a string is fretted and plucked. This stiffness and change in tension will have varying effects on each string diameter and type, which is why the strings need different end lengths. The most common and traditional goal is of course to reference the 12th fretted note against the open string or octave harmonic, and adjust the lengths until they agree.

After having done this however, the rest of the notes along the board are left to the positions of the frets, and cannot easily be individually compensated. So on a 1907 Gibson mandolin, your 2nd and third frets will yield much sharper notes than modern, but a 20's-40's mandolin will ring flatter than today's. The upper frets will be sharper than today's on both the pre-teens and post 40's mandolins, but flatter than modern instruments on the 10's-30's mandolins. Many of the old systems were irregular spacings, so there are a lot of individual nuances which are all over the map.

Fret spacing is often taken for granted as a constant and reliable system, but proves to be anything but this. Martin guitars did not adopt the modern 12th root of 2 spacing system until the mid/late 70's, and Gibson acoustic instruments didn't make this shift until their production move to Montana 20 years ago. And though the intonation differences are minor (until you get to the uppermost frets, or try to compensate the nut), Gibson electric guitars still haven't adopted the modern standard of fret spacing.

Getting in to which results are "better" or preferred is another topic altogether, but there is no perfect universal solution. No matter what you do, there will always be compromises - even if you could get "perfectly" in tune, it will still only be to an imperfect and slightly out of tune modern standard at best.

[300win]

I suppose this is related, but I made the statement once that on guitars the "B" string needs to be tuned just a tad flat to sound correct. I was told I was wrong, but in my experience every single guitar I've ever played myself, if you tune the "B" open with a tuner it will not sound correct in a G, D, etc. chord. Now am I just imagining this or am I correct ?

[MikeEdgerton]

I've never noticed that. How could a B string be affected in an open G chord?

[Rroyd]

I would suspect that goes back to Big Joe's reference to "tempering" the tuning. Is the open B string in tune with both an E chord and a G chord, or do we "temper" it so it sounds OK with both?
I've read and heard a number of discussions in the past about the B string, (such as being a 3rd in a world of 4ths,) and various explanations for what seems to be a fairly universal complaint about its unwillingness to ring out in perfect harmony. To put it in a mandolin-related context, guitars often are played with mandolins, and should be kept in tune to provide the best possible support.

[David Collins]

It's affected in an open chord because we are playing on a flawed scale. Major thirds will always sound sharper than natural in equal temperament, so by flattening the B string you are trying to sweeten the major third to the G, bringing it closer to the natural 4:5 ratio.

The problem here is that once you start to sweeten intervals away from their equal tempered pitches and bring closer to natural harmony, you will inevitably shift other intervals further from their natural harmony.

Let's take your example of flattening the B. Now you've sweetened the major third interval between the G and B, which want's to be a pure 4:5 interval, which is roughly 14 cents narrower than our equal tempered major third. Switch to a C, and you're probably still fine, as aside from the major 4th interval between those strings being more tolerant to a little change, your nut height is probably too high meaning that you are sharpening the C on the B string. This sharpening negates much of your tuning change, and is likely the saving grace that keeps the major third between that C and open high E from sounding too wide. Open A would sound great, because the B string is still a major third to the G, plus a minor third to the open E - double bonus. I'm a bit surprised however, that you find the open D chord to be improved over standard tuning however, unless you are perhaps sharpening that string further by pressure without realizing it.

Remember that every major or minor chord contains both major and minor third intervals though - in a major chord the minor third is between the 3rd and 5th, and flipped the other way in a minor chord. Shift now to the open E chord, and the open B is asked to perform the role of the minor third to the A♭ on the G string, which sounds more natural as a 5:6 ratio, which is about 16¢ wider than our equal tempered scale. Since you've just narrowed this gap by flattening the B, it will make the A♭ on the G sound relatively sharp. Same applies to major bar chords like F and G, or minor bar chords like Bmin.

Any time you flatten an individual string, it will sound better when acting as a major third to the string below, or minor third the the string above. Same will apply with sixths, though opposite relative to major and minor. Fourths and fifths have a fair amount of wiggle room, and it won't likely suffer much in this role. If that flattened string is to serve as a minor third or major sixth to the string below, or major third/minor sixth beneath the string above it however, it will suffer to an equal degree that it would benefit the other way around.

Of course every instrument and player is different, and can tolerate subtle tweakings differently. A top or box with a very prominent pitch can throw off some fretted notes significantly, and different players find ways to best accommodate these nuances with slight tuning variations and fingering pressures. So if it works consistently for you, I certainly won't try to tell you that you're wrong.

In general though, what the gods of harmony giveth, they also taketh away. Try sweetening from equal temperament, and every improvement in one area will come with a cost in another.

[Big Joe]

Or...it could be that the nut is not slotted perfectly so when you push the string down on the first few frets it pulls the string a bit sharp, thereby making the B sound out of tune. Then again, it could be all of the things mentioned. "Perfect" is not very perfect in the real world . I hate the thought that "good enough" is good enough, but in reality there is only so far one can go to eliminate the problems associated with our scales. Certianly fan frets have won some hearts, but I have not heard one that sounded better than regular frets, and I think it would drive me nuts trying to play it!

[zekelittle]

Hi All, I just wanted to chime in with my discoveries as a builder
struggling with bridge compensation. The pics below show what I'll try to say..
I have had good luck using a fixed (nonadjustable) bridge on these 5-string
acoustic/electric mandos that I build...they give a much bigger and richer sound.
The compensation is done by fitting the bridge to the top so that it is sloped.
The adjustment is done by moving the bridge to match the 12th fret and the
1st harmonic on the e-string and the c-string. Using the strings sets I get
from Martin at emando.com (11,15,26,40,50), the inside harmonics are ~perfect.
I haven't tried to build a bridge for an 8-string, but it should work the same by adjusting
for pairs.......zeke

[nvanlaar]

Not to hijack this, but I am making a solid bridge out of some scrap rosewood and am wondering how do you figure out the compensation needed in a bridge? Sure I can copy the old adjustable bridge, but who says it's right in the first place (besides, where's the fun in that? ).

Thanks for any pointers.
Nick

[re simmers]

Has anyone had a mandolin that tuned perfectly (or near perfect) on each string down to the 12th fret?

Bob

[Rob Grant]

Nick wrote:
"Not to hijack this, but I am making a solid bridge out of some scrap rosewood and am wondering how do you figure out the compensation needed in a bridge?"

FWIW: I actually use a six string electric archtop bridge (see Paul's photo above of a four string) to determine the positon of the ramps for the bridges I make for my mandos. I put the heavy adjustable in place, set the instrument up (string height) and then adjust the ramps for compensation. I then remove the bridge and basically copy the details to a lighter, non- adjustable ebony bridge blank.

[Paul Hostetter]

Has anyone had a mandolin that tuned perfectly (or near perfect) on each string down to the 12th fret?

Many. Why?

[re simmers]

Paul,
I've never owned one or borrowed one that wasn't a little off one way or another on several strings by about the 9th or 10th fret. ?

Bob

[Paul Hostetter]

Dang, that's regrettable. The shorter (13") scale flatback mandolins like Martins, bowlbacks and most of the Lyon and Healys were a bit rugged to tune, but the longer scale ones, modeled after Gibson, can be dialed in pretty well, at least to the extent that the frets themselves are set accurately. That's another discussion.

Gary Watkins just wrote me off-list asking where he could I get one of the tune-o-matic bridges for the mandolin and the compensated banjo that I posted above. Full disclosure:

1) the tune-o-matic bridge is an artifact of Photoshop, it doesn't really exist. I wish it did, but I had to make it up. But as Rob Grant points out, you can adapt a simple tune-o-matic guitar bridge to do the job. In an earlier, shadier part of my life I played a lot of electric guitar and came to deeply appreciate the tune-o-matic bridge because it completely solved intonation problems and demystified the issue. Obviously they're only acceptable on electric instruments (they weigh a ton and suck all sound right out of the strings), but the insights I gained from them carried over beautifully to acoustic instruments of all sorts.

2) the banjo bridge I showed is one of a couple of hundred I've made for people who are obsessed with banjo intonation. Trial and error in action. Ironically the best banjo players I work for use uncompensated bridges and just live with it. But it's fun to fool with these things. Banjos are closer to rock guitars than almost any other instrument: low (low) tension, lots of intonation issues. Guitars and mandolins are much easier.

The standard Gibson compensated bridge is at least 90% effective as a model. Not perfect, but as a template, it makes playing and tuning really tolerable. I have an appointment with one of my better pro mandolin players to tweak his bridge (1916 F-4 with original board - ulp!) to move the D point of contact forward a little. Now that he's settled on the strings of his dreams, and the ideal action, it's now safe to move past the Gibson template and amend bridge top to get him from 1-12 on all four courses in tune.

Another issue that's often overlooked is that most players, when they're sitting in a quiet room, with fresh strings on their mandolin and so on, carefully test intonation, and make a judgment. What they overlook is how they really play in sessions and at gigs, which quite often involves a pick attack way beyond their parlor evaluation session, and the tendency to press way harder with their left hand upon the strings in the line of duty, which tends to bend them a bit and make them play sharp. For some of those players I often adjust the bridge to intonate a little flat, since I know they'll blast it sharp in real-life playing situations. It's a complicated issue, but not that complicated, fortunately.

[David Collins]

If you want to actually calculate where the offsets should land, it's not terribly difficult to measure the intonation errors on an existing bridge and adjust from there. You can set up a bridge perpendicular to the strings and adjust one string to 0¢ at the 12th fret. Or if you don't mind an angled bridge (or actually need it angled to fit the intonation points of the outer strings), you can intonate both the outer strings this way. Then with a good tuner which can accurately measure errors in cents (like a strobe tuner) you can measure how far the others are off. If a string is flat, you divide the speaking length (12th fret to saddle) by the 12th root of 2 to the power of however many cents you are off. If it's sharp you multiply it by 2^(1/1200) to the ¢ power. Then subtract the speaking length you started with from this result, and the difference is how far the saddle point has to be moved from it's current position. Get used to the formulas and save the constant of 2^(1/1200) in your calculator's memory, and it takes a few seconds to calculate for each string.

Or if you want to avoid the math, on a standard 13_7/8" (or thereabouts) scale length, you will end up moving the saddle back or forward by about .004" per cent. For guitars I have a pile of dummy saddles of varying widths and radii that I use for testing, ramped all the way to the front. I shim and adjust them in a mock setup, measure the errors in cents, and calculate the needed compensation (comes to around .007"/1¢ for most guitar scales), and shape my final saddle accordingly.

This is just a quick and easy tool for estimating changes relative to an observed system. Paul hit it quite accurately though, in pointing out that changes in playing style will affect much greater changes than the seemingly precise calculations I listed may purport to achieve. In the end, intonation is best set by being able to estimate the real world end use. It's why I approach intonation differently for a fingerstyle guitarist getting setup to go in to the studio than I would for a heavy hitting bluegrasser going to a festival, or rock or blues player who spends most of their time playing in clubs. It's really only an approximation at best, but being mindful of the end playing style can serve you well to get as close as possible.

Has anyone had a mandolin that tuned perfectly (or near perfect) on each string down to the 12th fret?

I would say that no, no one ever has, and no one ever will on an instrument with 12 predetermined semitones in an octave. To be fair, I'll admit this is an argument of semantics, though I believe one worth making in discussions of tuning and intonation. In practice, yes, plenty of instruments can be set up to sound just fine across the board, but I would not qualify each note as perfectly or near perfectly "in tune", but rather near perfectly intonated within the limitations of our tempered scale.

It's an argument that some piano tuners may make that even when they "tune" a piano, they are never truly tuning it, but simply tempering and intonating it. This may sound like a purist stance on terminology, and indeed it is. I say it however, simply to emphasize and remind that "perfectly in tune" by today's standards will not yield perfect harmony in all intervals, and expectations and playing styles still need to be adjusted to work within our scale.

[re simmers]

Thanks Paul & David & Joe. My mandolins are close, but they are not perfect. David, your comments remind me of an elederly gentleman who tuned our church's grand piano. He carried around one of those large Boss tuners but never used it. He said perfect pitch across the board was not possible. He also said he could set the tuner at different places in the church, at different temperatures and humidity, room full of people or empty, carpet & padded pews verses wood floors & wood pews, high ceilings vs. low......and in the end the tuner was subjective. He relied on his 80 year old ears to tune it.

Question. When you have a mandolin "set up" what does that entail.......

Bob