The joys and pains of tuning, Part II (b)

One of the most frustrating problems that many guitarists experience is getting open chords to play in tune on their instruments. How many players have had their guitars properly set up, with the action, intonation, truss rod, and string height at first fret all carefully adjusted only to find that open chords sound terrible? I certainly have. The instinct when this happens is to start messing about with the intonation at the bridge, which will make no difference to the issue at hand, and will only create new problems elsewhere on the fretboard.

The problem is with the nut. It’s in the wrong place, usually too far from the first fret, meaning that all notes at the first three or four frets will be sharp; and the reason that messing around at the bridge won’t help is that any adjustment you make there will have virtually no effect below the fourth fret.

This situation arises quite a bit, and it happens because when some guitar makers calibrate and cut the fretboard, they will cut it for the nut at the zero point of the scale length (the scale length being the distance from the front edge of the nut to the centre of the bridge). And there’s where the problem lies. The nut shouldn’t be at the zero point of the scale length, it should sit slightly short of it. So, some compensation is needed, just as it’s needed at the bridge to adjust for the fact that the strings are stretched whenever you push them down to the frets. In effect, intonation is set at both ends of the strings.

The solution is to move the nut to the correct position, although, as it turns out, the correct position can vary from guitar to guitar. This might seem like you’re changing the scale length, but that’s not quite how it works. The scale length is chosen by the makers (25.4 inches for Martin, 24.75 inches for Gibson, etc.) and from this measurement the fretboard is calibrated using the 17.817 rule. This is where the scale length is divided by 17.817 to give the position of the first fret, the remainder is divided by 17.817 to give the position of the second fret, and so on. Any compensation which is then made to the nut end of the fretboard is needed because, even when the strings are as low as possible at the first fret, the act of pushing the strings down on to the fret is enough to make them play sharp.

I’ve developed a method for nut compensation that has worked with every guitar I’ve tried it on, and I’ll go through it now. The first thing that’s needed is a sufficiently accurate tuner. Pedal tuners aren’t really suitable, and any tuner apps I’ve tried just aren’t accurate enough. In my opinion, this tuner:

tuner 1

the Korg GT-120, is the best digital tuner out there. The needle is smooth and accurate, and the tuner is responsive whether you’re using the built in mic, a clip on one, or a cable for electric or electro-acoustic guitars.

Using the tuner, let’s have a look at the problem at hand. Here’s the reading for the in tune open G string of a Sigma guitar I worked on.

tuner 2

The needle is dead centre, and both the red pointers are on. Now, here’s how it was at the first fret, G#.

tuner 3

As you can see, it’s quite a bit sharp. This will make an open E chord sound pretty nasty. Maybe you’d instinctively lower the G string a bit, but then it would be flat in an open C chord, and you’d end up going round in circles. The other strings are similarly sharp, which means that all fretted notes are going to sound pretty out of tune in relation to open notes over the first three or four frets.
The tool I use to trim the fretboard is a Tusq saddle blank with some medium sandpaper attached by double sided tape.
sanding block
I make sure that the sandpaper is carefully trimmed at the bottom edge so that only wood from the end of the fretboard is removed, and not from the bottom of the slot.

This is a long process; sand back the end of the fretboard a bit, replace the nut (without glue at this stage), and check the intonation at the first fret. Repeat till the first three frets are in tune on all strings. When replacing the nut, the nut slot will obviously be wider than before, so I build the nut up at the back using a mixture of superglue and baking soda, like this:

and then sand it down to fit, like this.
nut 2
This has to be repeated each time you remove wood from the end of the fretboard. When it’s done, a new nut can be made, although most times I’ll just sand it smooth, polish it and keep the same nut. Another approach is what I did with this Strat, where a piece of rosewood veneer was used to fill the gap left by moving the nut forward.
Here’s that G# again after the process is complete.
tuner 5
It’s spot on, as are all the other strings.

Although this is a laborious process, and it can certainly cost you a few sets of strings, the good thing is that once it’s done, it’s done. It’s a permanent fix. The difference is remarkable. Open chords play beautifully in tune (according to equal temperament tuning, of course), tuning is improved across the fretboard, and playing with a capo needs no retuning.

The joys and pains of tuning, Part II (a)

The joys and pains of tuning, Part II (a)

If you think about it, getting a piano to play in tune is a simpler concept than getting a guitar to play in tune. This is because, on a piano, all the notes are ready made: eighty-eight of them all lined up, and all you have to do is tune each of the strings (or group of 3 strings for higher notes) correctly and you’re ready to go. Obviously, this is a huge simplification of the enormous skill required to properly tune a piano, but we’re talking conceptually here.

With a guitar, only six notes are prepared in advance: the open strings. All the other notes have to be made by altering the length of the strings, which is achieved by pressing them against the frets. And this is where the concept is more difficult: all of the notes being in tune relies on the fretboard being properly calibrated so that the frets are exactly a semitone apart, on the bridge and saddle (or saddles) being in the right position so that the octaves at the 12th fret are in tune, and, just as crucially, on the nut being in the right place so that the first few frets are in tune.

For the last few decades, the use of computer numeric control (CNC) machines has become the norm in guitar factories for many operations, including calibrating fretboards. This has led to greater consistency, more efficient use of materials, and very accurate fretboards, so when guitars have tuning problems (and they do, from budget models to top of the line) the issue is virtually never the fretboard.

There can be problems with the bridge, but not often. On electric guitars bridges are usually fully adjustable for action and intonation, so a bit of time spent with a screwdriver, an allen key, and a tuner will sort out your octaves at the 12th fret. Stratocaster style bridges, like this:

tuning image 1
have plenty of forward and backward travel in the saddles, so there’s almost never an issue there. Gibson tune-o-matic style bridges, like this:

tuning image 2
have less travel in the saddles and, occasionally, a saddle will run out of room before the intonation is correct. In this instance there are bridges available with more saddle travel that fit directly in place.

Acoustic guitar bridges are a different proposition, as they’re glued to the top of the guitar with a slot routed for the saddle. Compensated saddles are pretty much ubiquitous these days, usually with the low E and B strings sitting further back than the other strings, like this:

tuning image 3
and, for the most part, they work fine. Sometimes it might be necessary to slightly reshape the top of the saddle, but that’s fairly easily done.

Every once in a while, a bridge will be put on in slightly the wrong position. In the case of my Sigma SDR-28H, the bridge is just under 2 millimetres too far back, the upshot being that, even with the saddle shaped so that all the strings sit at its front edge, the D, G, and high E strings were all slightly flat at the 12th fret. Filling the saddle slot and routing it in the correct position wasn’t an option because the saddle is close to the front of the bridge. I decided to make some little extensions for the strings in question and glue them to the front of the saddle. Here’s how it ended up:

tuning image 4
It took a lot of time and patience to shape these little pieces (which are made from GraphTech Tusq, the same material as the saddle) and adjust them so that the 12th fret octaves were in tune. I also had to make sure that the string heights remained unaltered at the points where the strings pass over the extensions, which meant reshaping the back of the saddle slightly at those points, but it all worked out fine, and the guitar is now in tune at the 12th fret on all the strings.

Often though, all this is not enough. How many guitar players have spent time setting up their guitars, carefully adjusting the action and intonation, only to find that they can’t get open chords to play in tune? I certainly have. The problem in this case is with the nut, an area of guitar setup which is often overlooked, and I’ll be dealing with this in Part II (b).

The joys and pains of tuning, part I

The joys and pains of tuning, part I

There’s an old joke that says: “Guitarists spend 90% of their time tuning, and the other 10% playing out of tune”. There’s certainly some truth in this because, as much as we love guitars, there’s nothing can drive us to near insanity like trying to get them in tune.

Most of the tuning problems that guitarists encounter stem from two sources: 1) a lack of understanding of the equal temperament tuning system that the vast majority of western music employs, and 2) flaws in a guitar’s construction. I’m going to tackle the first of these in a fairly simple way in this post, and deal with the second in Part II.

Equal temperament tuning is the system which has been used since about 1750 whereby, for instruments of fixed pitch (like piano and guitar, where the smallest interval you have is a semitone), the octave is divided into 12 equal semitones. This means that, when playing chords, some notes sound slightly out of tune (some more than others) but the amount of out of tune-ness is the same for all chords in all keys.

Think of it this way: on a guitar (and a piano), F# and Gb are the same note, but strictly speaking, they’re not. There is a gap between them (an example of a phenomenon called the Pythagorean Comma), but equal temperament tugs at the ends of both notes and pulls them together. This is why, for example, the F# note on the second fret of the high E string sounds perfectly in tune as the root of a first position F# chord, but sounds quite sharp as the major 3rd of an open D chord. The same note will also sound very slightly flat as the 5th of a first position B minor chord. In fact, for all of these chords to sound perfectly in tune, each F# note would have to be slightly different, and the same also goes for all other notes. Achieving this would mean that a guitar would need to have about 30 frets to the octave rather than 12, which is not really a practical proposition.

So, what we’ve ended up with is a tuning system where, in all chords in all keys, 5ths are 1.96 cents flat of the pure pythagorean intervals, 4ths are 1.96 cents sharp, and Major 3rds are 13.69 cents sharp of the pure interval. That’s more than an eighth of a semitone sharp (a cent being one hundredth of a semitone), which is why those of us who are sensitive to tuning struggle with them. In fact, in equal temperament tuning, the only intervals which are (or should be) perfectly in tune are octaves and unisons. This table shows the difference between the pure or “just” intervals and the tempered ones.

music table

This is why tuning to a chord doesn’t work. The tendency will be to tune the chord to pure, rather than tempered, intervals, which will make all other chords sound terrible. If you’re tuning by ear, only unisons and octaves should be used. The thing to do is to get used to how chords sound in equal temperament; to train your ear and learn to expect that Major 3rds are going to sound sharp and 5ths flat, and so on. Do this, and you’ll be much happier with your guitar.

All this, of course, depends on your guitar being set up properly, and any flaws in its construction being dealt with, which I’ll talk about in The Joys and Pains of Tuning Part II.

Featured image: Tuning by Buzz [CC-BY-NC-NC 2.0] via Flickr

How to stop worrying and embrace string rattle

Throughout my years of teaching guitar, and also setting them up, there is one thing that seems to bother more students and players than anything else, which is odd, because it doesn’t seem to bother the musicians who made them want to play in the first place. It’s string “buzz”, or what I refer to as “rattle”.

The first thing to do is to ascertain the difference between string buzz and string rattle (also, sometimes, called string slap).

String buzz is an unwelcome phenomenon caused either by the string not being pressed firmly enough to the fret, or by a vibrating string coming into contact with the next fret, because that fret is too high, or because the string is pressed against a worn fret, making it lower than the others (or, in the case of an open string, the first fret, because a nut slot is too deep). In these cases, the string will sound fuzzy no matter how softly it is struck.

String rattle (or slap), on the other hand, is where a string is struck with sufficient force, on a properly set up guitar, for it to vibrate against the next fret, or the first fret if the string is open. There’s no doubt that this can happen inadvertently, but good players can do it deliberately as an effect.

The best way to illustrate this, I think, is with a few examples. I’m only going to reference two guitar players here, David Gilmour and Neil Young, both of them legendary and highly regarded by generations of players and music fans alike. Neither of them are particularly technical players, but both are very expressive, and both are great for the purpose of this post.

Here’s David Gilmour, of Pink Floyd, playing an acoustic version of Breathe from the Dark Side of the Moon album on a Martin D-35.

Listen to the low E string when he digs into the E minor chord. It rattles. Look at the bridge saddle to get an idea of how low the action is on the guitar. This, and the rattle it engenders, is a deliberate choice by Gilmour. The guitar plays cleanly with a moderate attack, but when he attacks it more forcefully, the effect is of the guitar growling, and it makes the guitar sound alive and organic.

The same is true of his electric guitar setup and sound. Here’s Have a Cigar from Floyd’s Wish You Were Here album, played on a Fender Stratocaster.

Listen to the intro where the guitar part is more isolated, and hear how much the low E string rattles, both open, and at the G note on the 3rd fret (the other wound strings will do the same to a degree). The point again is that he’s digging into the strings quite hard, and the result is the growling, snarling effect you hear.

Here’s a Neil Young example, and it’s a cracker, that illustrates the main issue concerning string rattle; technique.

This is You and Me from Neil Young’s 1992 album Harvest Moon. This was most likely played on his Martin D-45, and it’s in Drop D tuning (low E string tuned down to D).

This track is strummed, but I believe he plays it with his fingers and not a pick, hence the softer tone, although the playing is still dynamic. Note how there’s barely any string slap at all until the first chorus begins at 1:28, when he starts to lean into the low string with his thumb, and then it only happens when he wants it to.

And that’s the point; to have your guitar set up properly and to learn how to get it to do what you want. This means knowing how hard to attack the strings, and at which point along the string length, to get the tones and effects you want, all of which, of course, takes time and practise. Playing close to the end of the neck will yield a thick, bassy tone, and will make string rattle hard to control. Move close to the bridge, and the sound will be brighter and harder. In between these two extremes is usually best, somewhere between the centre of the sound hole and the edge nearest the bridge.

To finish here’s Neil Young playing Old Man at the BBC in 1971 on the same Martin D-45. This audience got a preview of what would be a highlight of 1972’s Harvest album.

All those hammer-ons wouldn’t sound so good if the action were too high, and the guitar wouldn’t sound so vibrant either. Lots of strings rattle here, open and fretted ones, and all of it’s deliberate.

Embrace string rattle. Learn to control it. It’s all part of playing guitar.