Measuring string compensation

Charting the 'sweet spots'

This is a simple routine that lets you come up with the exact location where you need to position the bridge. It also lets you determine whether you need a compensated bridge or not and if so, it tells you the exact amount of compensation you require for each of the strings. Also, if your bridge needs to be positioned on an angle this routine will tell you exactly what the angle is for your banjo . Read these instructions carefully but don't get intimidated, they are pretty easy to follow.

Knowing where and how to position a banjo bridge is par for the course in banjo land, it's required skill just like knowing how to tune your strings. Banjo bridges do "travel" on the banjo's head so you need to check if its still at the proper spot about once a month or so. In other words, don't rely on others to do it for you, "you gotta learn how to pick yer own nose..."

In case you are not quite to sure about these instructions, take a trip to your local music store and ask them to show you how to set up the intonation on an electric guitar by adjusting the moveable saddles. Looking at the way this is done ought to give you plenty clues about what you'll be doing with your bridge. In case you're wondering, sure enough, that's where I got the idea for making my custom compensated bridges the way I do.

If, after going through steps, it turns out you need a compensated bridge then make sure you've settled on your favourite string gauges, bridge height, string spacing and neck angle before ordering a custom compensated bridge - any changes here and all bets are off and you need to re-measure.

Please note: to come up with accurate measurements you need to:

  • use new strings: old strings often create intonation problems 
  • use a bridge with a thin top: 2 ~ 2.5 mm thickness is ideal. Thicker than 3 mm is too thick for this purpose and I don't recommend you use budget priced bridges as, unfortunately, they are known to be intonation unfriendly. By the way, most of the original "came-with-the-banjo" bridges fall in the no-frill budget category so use a quality aftermarket bridge for this routine. In fact, using quality aftermarket bridges more often than not, will make intonation problems caused by no-frill bridges go away completely and you can merrily skip this routine. If you don't have a thin top bridge it's real simple way to make a cheap dummy test bridge yourself for this occasion, here's how .
  • play the chimed notes on the 12th fret. Here's how: you touch the string ever so slightly directly above the 12th fret, not behind the fret the way you do while playing normally. Many people forget, or mix this up, so let me repeat:  touch the string directly above the 12th fret itself, pick the string and immediately take your finger off the string you're chiming. You now hear a clear dreamy bell-like sound is this is what you'll be using to compare the pitch of that tone to the pitch of the string when you fret it behind the 12th string the way you normally do.
  • by the way, going through this measuring routine takes less time than it does to change a set of strings :))) 

Let's get started: chart the 'sweet spots' for each string starting with the first string, but before you do: be careful! Many bridges are very brittle and can snap into several pieces that can come flying at your face real easily while you move them! You might be wise to slacken the tension of the strings first, especially with thin bridges, before you grab a hold of your bridge between your thumb and index fingers of BOTH hands and move it around.

To avoid any confusion, you're measuring the sweet spots of all strings relative to the first string so the "sweet spot" for the first string must be zero. One more thing defore you dig in: if your 5th string sits on top some kind of a slotted pip thingie behind the 5th fret (up in the air above the 5th fret instead of resting on the 5th fret itself) then there's no point in compensating it and you use a zero just like the first string.

  1. Position the bridge at a 90 degree angle to the third string (the normal, proper position)
  2. Move the bridge to where you can play a chime at the 12th fret (or 19th fret for greater accuracy) starting with the first string. 
  3. Now play the same note fretted, also at the 12th fret (or 19th fret for greater accuracy)
  4. If the pitch of the fretted note is higher, move the bridge towards tail piece (away from the neck). If you don't trust your ears to tell whether the pitch is higher, lower or the same, use an electronic tuner.
  5. Pitch lower? move the bridge away from tail piece (towards the neck)
  6. Mark the spot on the head where the pitch of the chime equals the pitch of the fretted note. Use a pencil to mark the spots.
  7. Repeat steps 2 through 6 for all strings - keep in mind, the fifth string's chime, or harmonic, is on the 17th fret instead of the 12th like the other strings.
  8. Draw a straight line (or use a sticky label stickers, sticky, green painters tape or whatever) at the first string's zero point at a 90 degree angle to the 3rd string.
  9. Measure the distance from the zero line to the marks you've made for all strings

If your 'zero line' off-set measurements show zero for all strings - no matter what you've been told, you simply don't need a compensated bridge, period. Don't be surprised though if your results show something like this:

String Zero line off-set
#1 0 mm (always zero)
#2 2 mm
#3 4 mm
#4 3 mm
#5 0 mm

Down & dirty: for a quick way to get your bridge close to the proper position, "good enough for now," follow steps 1 through 5 until you have the 1st string properly intonated then do the same thing for the 4th string only while making sure the bridge stays in the same location for the 1st string. Chances are the bridge now will no longer be at 90 degrees to the 3rd strng - instead it might be angled, the 4th string side being closer to the tail piece. Like I said, "good enough for now."

If the measured spots line up in a straight line,
whether the bridge  is angled or not,
then despite what anyone else,
especially marketing people, tell you:
then you DO NOT need a compensated bridge. 

When you've finished this routine and your numbers look something like 0-0-2-0-0 > all strings are fine except for the 3rd string, here's a little secret: most strings, except the 3rd (and sometimes the 2nd string) are usually quite forgiving, intonation wise. In this case the 3rd string notes sharp so logically speaking, it needs to be lengthened by a +2 mm offset. Try this: grab the bridge at both sides and pull it towards the tail piece about 1 mm and recheck the fretted notes compared to the chimed notes. Things are fine but the 3rd string still a tad sharp? Move it another 1 mm same direction and compare fretted and chimed notes again. You may have to tweak the 1st or 4th string a tad but don't at all be surprised that all string now intonate darn near perfect.

For most banjos the intonation sweet spots line up in a straight ZERO LINE , whether the bridge is angled or not. Like I just mentioned, this means you don't need a compensated bridge. Over the years I've come across some extreme cases where the intonation offsets reached about 5 to 8 millimeter values, especially on the 3rd and 4th strings. If you come up with number higher than 7 or 8 mm you better re-check the proper location for string 1 as something is likely to be out of whack. Either that, or you're probably using a bridge that's unusually tall or wide.Then again, you never know, maybe you got yerself a real heavy duty twister... By the way, in all the years I've been making my custom compensated bridges I've only come across 3 or 4 of them where the offset value was negative - meaning of course, that the string length needed to be shortened instead of the usual need to be lengthened. It's highly unusual for any of the string lengths to require shortening and yes, that definitely includes the second string. 

I'm sure you've noticed, the measurements are all in millimeters. To me they're less confusing then them durned little and big and bigger stripes on the inch rulers (I've looked at them wrong stupid stripes once too often...). You can get rulers that measure in millimeters in a dollar store near you.

Once you've done the measuring you know beyond the shadow of a doubt whether you do, or do not, need a compensated bridge for this particular banjo and for the way this particular banjo is set up. You'll also know the exact amount of compensation required, based on science and you no longer have to rely on anecdotal evidence, myths or "my buddy told me." If nothing else, you'll learn about the finer workings of your banjo. If it turns out you do need compensation you shouldn't be surprised at that, you'll now know exactly what to do about it. With this sweetspot routine there simply no longer is a reason to guess. What you're your aiming for is the ultimate sound and playability of YOUR banjo, not someone else's.

Please note: I have come to feel pretty strongly that the only proper way to address intonation problems is to go it the custom compensated route. If a compensated bridge is not made according to measurements done on your banjo then it's a generically compensated bridge based only on guesswork. Generic compensation simply cannot do the job custom compensation does and my own banjos deserve better than having to settle for "close enough," or "about this much." If you're thinking "yeah, but the second string's always out anyways" think again - with cumstom compensation this simply does is no longer true. Yup, with a properly compensated bridge there's no need to tune your 2nd string flat by five cents.

When perfection is doable, why settle for less. Perhaps overzealous, maybe not too smart marketing wise, but as of November 2006 I stopped making and selling generically compensated bridges because, plain and simple, they don't cut it and I refuse to put my name on a product like that. How could anyone pretend to know by what and how your intonations are caused without ever having seen or touched your banjo?

By the way: if you inflict this routine on a few different banjos you'll soon discover that for banjos that do need a compensated bridge that the required correction measurements are never the same from banjo to banjo, they're always different. This is THE reason that generically compensated bridges fail to solve intonation issues. When shopping for a compensated bridge ask the maker(s) how, and by how many millimeters each string is compensated (strings shortened or lengthened?). Oh, don't be surprised if they can't, or don't want to, tell you those measurements. If their numbers do not agree with the ones you just measured by using the routine above you'll know that their particular bridge is definitely not the one you need and you'd be wise to keep shopping around or, better yet, drop me an email.

There's two ways to get a compensated bridge: take somebody's word for the "I know what I'm doing,"  or the "about-this-much" approach OR the exact measurement solution. With the latter approach you'll never have to use the word 'compromise' again. Think twice before deciding on generics.

If you'd like to order a bridge whether straight, or compensated, please go to this page to let me know the details. Your support is greatly appreciated.

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